The document discusses the contents of Unit 1 of the subject ME 8593-DESIGN OF MACHINE ELEMENTS. It includes an introduction to the design process and factors influencing machine design. It also discusses selection of materials based on mechanical properties, preferred numbers, fits and tolerances. Additionally, it covers direct, bending and torsional stress equations, impact and shock loading, calculation of principle stresses for various load combinations, eccentric loading, curved beams, crane hook and 'C' frame. The document also mentions factor of safety, theories of failure, design based on strength and stiffness, stress concentration and design for variable loading.
This document contains a question bank for the Design of Machine Elements course covering various topics in 5 units. It includes over 180 questions related to steady and variable stresses in machine members, shafts and couplings, joints, energy storing elements, and bearings. The questions cover topics such as stress analysis, materials selection, fits and tolerances, failure theories, stress concentration, fatigue design, and design of common machine components. The document also lists the textbook and references used for the course.
This document describes the design of a worm and worm wheel gear set. It begins with an introduction to worm gears and their applications where fast braking, low noise, or space constraints are important factors. The document then outlines the design process, which involves selecting design parameters like tooth count and lead angle, calculating loads, strength, and efficiency. The design problem provided is to transmit 22 kW between shafts 225 mm apart with a 24:1 transmission ratio using phosphor bronze materials. The document details the step-by-step design process to solve this problem and size the worm and worm wheel gears.
UNIT 4 Energy storing elements and Engine components.pptxCharunnath S V
This document discusses various energy storing elements and engine components. It describes springs, including helical springs, leaf springs, Belleville springs, and concentric springs. It discusses the material, design, and stresses in helical springs. It also covers flywheels, connecting rods, and crankshafts as key engine components that help store and transmit energy within an engine.
The document discusses mechanical measurements and metrology. It covers topics like limits, fits, tolerances and gauging. Specifically, it defines tolerance, describes different types of tolerances like unilateral, bilateral and compound. It also discusses interchangeability, selective assembly, fits, tolerance grades and general terminology used in metrology like basic size, actual size, deviations etc. The objective is to equip students with knowledge of these important concepts in mechanical measurements.
This document provides an introduction to bearings and bearing design. It defines bearings and their purpose of supporting moving machine elements while allowing relative motion. Bearings are classified based on the direction of load and type of contact. Rolling contact bearings like ball and roller bearings are introduced, which have lower friction than sliding contact bearings. The document outlines the main parts of a ball bearing and provides steps for selecting an appropriate bearing for an application involving a 40mm shaft with 5000N of radial load and 3000N of thrust load operating at 400rpm. Through calculations, ball bearing SKF No. 6308 is determined to meet the load requirements.
Power screws convert rotary motion into linear motion for power transmission. There are three main types of power screw threads: square, Acme, and buttress. Square threads are strongest but hardest to manufacture, while Acme threads are easier to machine but can only handle lower loads. Buttress threads are designed to handle extremely high loads in one direction. The efficiency of power screws depends on whether it is raising or lowering a load. Power screws have various applications where linear motion is needed, such as jack screws, lathe lead screws, presses, and material testing machines.
Jigs and fixtures are devices used to securely hold or locate a workpiece in a machining process. A jig locates and guides a cutting tool, while a fixture secures a workpiece to a machine table. They both help improve accuracy and efficiency. Key components include a base, locators to precisely position the workpiece, and clamps to securely hold it in place against cutting forces. Common types of locators are cylindrical, conical, and V-shaped to accommodate varying workpiece sizes. General principles for jigs and fixtures are that they reduce idle time, enable clean machining, use standardized parts, allow for coolant flow, have hardened locating surfaces, prevent incorrect assembly, and securely position workpieces
This document contains a question bank for the Design of Machine Elements course covering various topics in 5 units. It includes over 180 questions related to steady and variable stresses in machine members, shafts and couplings, joints, energy storing elements, and bearings. The questions cover topics such as stress analysis, materials selection, fits and tolerances, failure theories, stress concentration, fatigue design, and design of common machine components. The document also lists the textbook and references used for the course.
This document describes the design of a worm and worm wheel gear set. It begins with an introduction to worm gears and their applications where fast braking, low noise, or space constraints are important factors. The document then outlines the design process, which involves selecting design parameters like tooth count and lead angle, calculating loads, strength, and efficiency. The design problem provided is to transmit 22 kW between shafts 225 mm apart with a 24:1 transmission ratio using phosphor bronze materials. The document details the step-by-step design process to solve this problem and size the worm and worm wheel gears.
UNIT 4 Energy storing elements and Engine components.pptxCharunnath S V
This document discusses various energy storing elements and engine components. It describes springs, including helical springs, leaf springs, Belleville springs, and concentric springs. It discusses the material, design, and stresses in helical springs. It also covers flywheels, connecting rods, and crankshafts as key engine components that help store and transmit energy within an engine.
The document discusses mechanical measurements and metrology. It covers topics like limits, fits, tolerances and gauging. Specifically, it defines tolerance, describes different types of tolerances like unilateral, bilateral and compound. It also discusses interchangeability, selective assembly, fits, tolerance grades and general terminology used in metrology like basic size, actual size, deviations etc. The objective is to equip students with knowledge of these important concepts in mechanical measurements.
This document provides an introduction to bearings and bearing design. It defines bearings and their purpose of supporting moving machine elements while allowing relative motion. Bearings are classified based on the direction of load and type of contact. Rolling contact bearings like ball and roller bearings are introduced, which have lower friction than sliding contact bearings. The document outlines the main parts of a ball bearing and provides steps for selecting an appropriate bearing for an application involving a 40mm shaft with 5000N of radial load and 3000N of thrust load operating at 400rpm. Through calculations, ball bearing SKF No. 6308 is determined to meet the load requirements.
Power screws convert rotary motion into linear motion for power transmission. There are three main types of power screw threads: square, Acme, and buttress. Square threads are strongest but hardest to manufacture, while Acme threads are easier to machine but can only handle lower loads. Buttress threads are designed to handle extremely high loads in one direction. The efficiency of power screws depends on whether it is raising or lowering a load. Power screws have various applications where linear motion is needed, such as jack screws, lathe lead screws, presses, and material testing machines.
Jigs and fixtures are devices used to securely hold or locate a workpiece in a machining process. A jig locates and guides a cutting tool, while a fixture secures a workpiece to a machine table. They both help improve accuracy and efficiency. Key components include a base, locators to precisely position the workpiece, and clamps to securely hold it in place against cutting forces. Common types of locators are cylindrical, conical, and V-shaped to accommodate varying workpiece sizes. General principles for jigs and fixtures are that they reduce idle time, enable clean machining, use standardized parts, allow for coolant flow, have hardened locating surfaces, prevent incorrect assembly, and securely position workpieces
Brakes are mechanical devices that absorb the kinetic energy of a moving object using friction to slow or stop its motion. There are three main types of brakes: mechanical, hydraulic/pneumatic, and electrical. Mechanical brakes use levers, springs, and pedals while hydraulic and pneumatic brakes use fluid pressure. Electrical brakes use electromagnetic forces. Common mechanical brakes include shoe, band, and internal/external expanding brakes. The first step in designing a mechanical brake is determining the required braking torque capacity based on the amount of energy to be absorbed. Brakes must also effectively dissipate heat to avoid overheating from the converted kinetic energy.
The document discusses machining processes and cutting tools. It provides definitions of machining and cutting tools. It describes:
- The importance of machining processes in manufacturing precise parts.
- Objectives of machining like high material removal rate and surface finish, low tool and power costs.
- Classification of cutting tools based on how relative motion is provided between tool and workpiece.
- Key terms related to cutting tool geometry like rake angle, relief angle, and their influence on tool strength and chip removal.
- Mechanism of chip formation and different types of chips produced.
1. Shaft couplings are used to connect shafts that are manufactured separately or to introduce flexibility between shafts. The main types are rigid and flexible couplings.
2. Rigid couplings transmit torque without losses but require perfectly aligned shafts. Flexible couplings allow for misalignment. Common rigid couplings are sleeve, clamp, and flange couplings.
3. Flange couplings use separate cast iron flanges keyed to each shaft end and bolted together. The flanges and bolts are designed to transmit the torque between the shafts. Flexible couplings like bush pin couplings introduce mechanical flexibility.
This presentation briefly tells about the classification of Gears. It includes information about spur, helical, bevel, herringbone, rack and pinion, internal and external gears.
The document describes a planer machine, which is used to generate flat surfaces and cut slots. It moves the entire workpiece beneath the cutting head on a reciprocating table. The main parts of a planer include the bed, table, column, cross rail, and tool head. The bed supports the machine and table, which holds the workpiece. The column and cross rail guide the reciprocating motion of the table and movement of the tool head, which can have multiple cutting tools. Planer operations include planing horizontal and vertical surfaces as well as slots. Safety precautions must be followed when using the heavy machinery.
The document discusses gears and their classification. It defines various gear types including spur gears, helical gears, bevel gears, worm gears, and rack gears. It covers gear terminology such as pressure angle and describes how parameters like pressure angle and center distance affect gear performance and interference. Methods to avoid interference include increasing center distance, tooth modification, and changing the number of teeth. Backlash is also defined as the clearance between mating gear teeth.
The document discusses worm gears and provides definitions and equations related to their design and operation. It defines worm gears as having large gear reductions from 20:1 up to 300:1. Worm gears are used widely in machinery because the worm can easily turn the gear but the gear cannot turn the worm. Key terms defined include lead, lead angle, velocity ratio, center distance, efficiency, and force equations. Design considerations like helix angle, module, and pitch are also addressed.
The document summarizes the key steps in the fixture design procedure: 1) locating, 2) clamping, 3) supporting, 4) applying cutter guides, and 5) drawing the fixture outline. It discusses locating and degrees of freedom, describing how locating elements are used to restrict the six degrees of freedom of an object. Specific examples are provided to illustrate how locating points can be applied to a rectangular block to restrict its motion and rotations. The document also discusses clamping elements, support, cutter guidance, and completing the fixture body. Common locating principles like six-point location, 3-2-1 principle, and 4-2-1 principle are explained.
This document provides an introduction to machine design and its various considerations. It defines machine design as the process of engineering design that involves designing machine elements and arranging them optimally to obtain useful work. Some key points covered include:
- Classification of machine design types including adaptive, development, and new design.
- Factors to consider in machine design such as material selection, forces on elements, size, shape, weight, manufacturing method, reliability, and cost.
- The general procedure of machine design including need identification, mechanism synthesis, force analysis, material selection, element design, modification, and drawing production.
- Considerations for manufacturability such as reducing part counts, modular design, and designing for
Design involves formulating a plan to satisfy a particular need and create something with physical reality. When designing a chair, factors like purpose, intended user (adult or child), material strength and cost, aesthetics, and ergonomics must be considered. Machine design uses technical information, scientific principles, and imagination to design machines to perform specific functions with maximum economy and efficiency. This document discusses various machine design considerations and principles like types of loads, material selection, and theories of failure.
ME6503 - DESIGN OF MACHINE ELEMENTS TWO MARKS QUESTIONS WITH ANSWERS ASHOK KUMAR RAJENDRAN
This document contains a question bank with multiple choice questions and answers related to the Design of Machine Elements course. It covers topics from the first unit on steady and variable stresses in machine elements. The questions are about materials selection factors, mechanical properties, common engineering materials, classification of machine designs, definitions of terms like loads, stresses, strains and more. The document is prepared by R. Ashok Kumar for the RMK College of Engineering and Technology.
1) The document discusses the design of shafts subjected to different loading conditions including bending, torsion, combined bending and torsion, fluctuating loads, and axial loads.
2) Formulas are provided to calculate the equivalent bending moment and equivalent twisting moment for shafts under various loading conditions.
3) Examples are presented to demonstrate how to use the formulas and determine the necessary shaft diameter based on allowable stresses.
The document discusses measurement and metrology of gear teeth. It begins by listing textbooks and references on the topic. It then outlines the learning objectives of understanding basic principles of measuring gear tooth parameters. The key aspects covered include defining gear tooth features, common errors in spur gears during manufacturing, and methods for measuring specific gear elements like runout, pitch, profile, lead, backlash, and tooth thickness. Common instruments discussed are the gear roll tester, Parkinson's gear tester, and measurement using a gear tooth vernier or the base tangent method over multiple teeth.
The document describes the design of a screw jack that can lift up to 3 tons. It identifies the need, outlines the research conducted, and describes the components designed. The team designed a screw, nut, handle, frame, and cup. Design calculations were performed to determine specifications. Materials were selected based on withstanding torsional, bending and axial loads. The conclusion discusses using a 5/8" acme power screw and improving the design with a two start thread and longer handle to reduce required force.
Unit 4- balancing of rotating masses, Dynamics of machines of VTU Syllabus prepared by Hareesha N Gowda, Asst. Prof, Dayananda Sagar College of Engg, Blore. Please write to hareeshang@gmail.com for suggestions and criticisms.
Basic types of screw fasteners, Bolts of uniform
strength, I.S.O. Metric screw threads, Bolts under
tension, eccentrically loaded bolted joint in shear,
Eccentric load perpendicular and parallel to axis of
bolt, Eccentric load on circular base, design of Turn
Buckle.
The document discusses the design of helical springs. It defines what springs are and their objectives, such as cushioning shocks. It describes common spring materials like music wire and different types of springs like cylindrical helical and leaf springs. The document covers stress analysis and deflection analysis of helical compression springs. It provides the basic design procedure for determining spring dimensions given inputs like load and deflection.
Unit 3 Temporary and Permanent Joints.pptxCharunnath S V
This document discusses various types of temporary and permanent joints, including threaded fasteners, riveted joints, and welded joints. It provides details on different types of riveted joints, methods of riveting, types of threaded elements, and thread terminology. The document also covers topics such as bolted joints, failures in bolts, stresses on threaded fasteners, and problems involving eccentric loading conditions.
There are four main types of grinding machines: surface grinding machines, cylindrical grinding machines, internal grinding machines, and tool and cutter grinding machines. Surface grinding machines are classified by spindle orientation and table movement. Cylindrical grinding machines include plain, universal, and centerless types. Internal grinding machines include chucking, planetary, and centerless types. Tool and cutter grinding machines are used to manufacture or resharpen tools and cutters.
The document discusses measurement and metrology of screw threads. It begins with definitions of screw thread terminology such as major diameter, minor diameter, pitch, angle, and forms of threads. It then describes methods for measuring the major diameter, minor diameter, effective diameter, and pitch of screw threads. The key measurement methods discussed are using micrometers, pitch gauges, and a tool maker's microscope. The goal is to understand principles and techniques for measuring characteristics of screw threads.
This document provides a syllabus for a Machine Design course. The syllabus covers the design of simple machine elements, shafts, keys, couplings, elements under fluctuating loads, power screws, threaded joints, welded joints, and mechanical springs. The course aims to teach students how to identify failure modes, design various machine elements to withstand stresses, and design elements subjected to different loading conditions. The syllabus is divided into 6 units that will cover these various machine design topics. Required textbooks are also listed.
This document provides information on the course ME 8593-DESIGN OF MACHINE ELEMENTS. The objectives of the course are to familiarize students with the design process, principles of evaluating component shape and dimensions to satisfy requirements, use of standards and catalogs, and use of standard machine components. The textbook and reference materials are listed. The course will cover topics such as stresses in machine elements, shafts and couplings, joints, energy storing elements, and bearings.
Brakes are mechanical devices that absorb the kinetic energy of a moving object using friction to slow or stop its motion. There are three main types of brakes: mechanical, hydraulic/pneumatic, and electrical. Mechanical brakes use levers, springs, and pedals while hydraulic and pneumatic brakes use fluid pressure. Electrical brakes use electromagnetic forces. Common mechanical brakes include shoe, band, and internal/external expanding brakes. The first step in designing a mechanical brake is determining the required braking torque capacity based on the amount of energy to be absorbed. Brakes must also effectively dissipate heat to avoid overheating from the converted kinetic energy.
The document discusses machining processes and cutting tools. It provides definitions of machining and cutting tools. It describes:
- The importance of machining processes in manufacturing precise parts.
- Objectives of machining like high material removal rate and surface finish, low tool and power costs.
- Classification of cutting tools based on how relative motion is provided between tool and workpiece.
- Key terms related to cutting tool geometry like rake angle, relief angle, and their influence on tool strength and chip removal.
- Mechanism of chip formation and different types of chips produced.
1. Shaft couplings are used to connect shafts that are manufactured separately or to introduce flexibility between shafts. The main types are rigid and flexible couplings.
2. Rigid couplings transmit torque without losses but require perfectly aligned shafts. Flexible couplings allow for misalignment. Common rigid couplings are sleeve, clamp, and flange couplings.
3. Flange couplings use separate cast iron flanges keyed to each shaft end and bolted together. The flanges and bolts are designed to transmit the torque between the shafts. Flexible couplings like bush pin couplings introduce mechanical flexibility.
This presentation briefly tells about the classification of Gears. It includes information about spur, helical, bevel, herringbone, rack and pinion, internal and external gears.
The document describes a planer machine, which is used to generate flat surfaces and cut slots. It moves the entire workpiece beneath the cutting head on a reciprocating table. The main parts of a planer include the bed, table, column, cross rail, and tool head. The bed supports the machine and table, which holds the workpiece. The column and cross rail guide the reciprocating motion of the table and movement of the tool head, which can have multiple cutting tools. Planer operations include planing horizontal and vertical surfaces as well as slots. Safety precautions must be followed when using the heavy machinery.
The document discusses gears and their classification. It defines various gear types including spur gears, helical gears, bevel gears, worm gears, and rack gears. It covers gear terminology such as pressure angle and describes how parameters like pressure angle and center distance affect gear performance and interference. Methods to avoid interference include increasing center distance, tooth modification, and changing the number of teeth. Backlash is also defined as the clearance between mating gear teeth.
The document discusses worm gears and provides definitions and equations related to their design and operation. It defines worm gears as having large gear reductions from 20:1 up to 300:1. Worm gears are used widely in machinery because the worm can easily turn the gear but the gear cannot turn the worm. Key terms defined include lead, lead angle, velocity ratio, center distance, efficiency, and force equations. Design considerations like helix angle, module, and pitch are also addressed.
The document summarizes the key steps in the fixture design procedure: 1) locating, 2) clamping, 3) supporting, 4) applying cutter guides, and 5) drawing the fixture outline. It discusses locating and degrees of freedom, describing how locating elements are used to restrict the six degrees of freedom of an object. Specific examples are provided to illustrate how locating points can be applied to a rectangular block to restrict its motion and rotations. The document also discusses clamping elements, support, cutter guidance, and completing the fixture body. Common locating principles like six-point location, 3-2-1 principle, and 4-2-1 principle are explained.
This document provides an introduction to machine design and its various considerations. It defines machine design as the process of engineering design that involves designing machine elements and arranging them optimally to obtain useful work. Some key points covered include:
- Classification of machine design types including adaptive, development, and new design.
- Factors to consider in machine design such as material selection, forces on elements, size, shape, weight, manufacturing method, reliability, and cost.
- The general procedure of machine design including need identification, mechanism synthesis, force analysis, material selection, element design, modification, and drawing production.
- Considerations for manufacturability such as reducing part counts, modular design, and designing for
Design involves formulating a plan to satisfy a particular need and create something with physical reality. When designing a chair, factors like purpose, intended user (adult or child), material strength and cost, aesthetics, and ergonomics must be considered. Machine design uses technical information, scientific principles, and imagination to design machines to perform specific functions with maximum economy and efficiency. This document discusses various machine design considerations and principles like types of loads, material selection, and theories of failure.
ME6503 - DESIGN OF MACHINE ELEMENTS TWO MARKS QUESTIONS WITH ANSWERS ASHOK KUMAR RAJENDRAN
This document contains a question bank with multiple choice questions and answers related to the Design of Machine Elements course. It covers topics from the first unit on steady and variable stresses in machine elements. The questions are about materials selection factors, mechanical properties, common engineering materials, classification of machine designs, definitions of terms like loads, stresses, strains and more. The document is prepared by R. Ashok Kumar for the RMK College of Engineering and Technology.
1) The document discusses the design of shafts subjected to different loading conditions including bending, torsion, combined bending and torsion, fluctuating loads, and axial loads.
2) Formulas are provided to calculate the equivalent bending moment and equivalent twisting moment for shafts under various loading conditions.
3) Examples are presented to demonstrate how to use the formulas and determine the necessary shaft diameter based on allowable stresses.
The document discusses measurement and metrology of gear teeth. It begins by listing textbooks and references on the topic. It then outlines the learning objectives of understanding basic principles of measuring gear tooth parameters. The key aspects covered include defining gear tooth features, common errors in spur gears during manufacturing, and methods for measuring specific gear elements like runout, pitch, profile, lead, backlash, and tooth thickness. Common instruments discussed are the gear roll tester, Parkinson's gear tester, and measurement using a gear tooth vernier or the base tangent method over multiple teeth.
The document describes the design of a screw jack that can lift up to 3 tons. It identifies the need, outlines the research conducted, and describes the components designed. The team designed a screw, nut, handle, frame, and cup. Design calculations were performed to determine specifications. Materials were selected based on withstanding torsional, bending and axial loads. The conclusion discusses using a 5/8" acme power screw and improving the design with a two start thread and longer handle to reduce required force.
Unit 4- balancing of rotating masses, Dynamics of machines of VTU Syllabus prepared by Hareesha N Gowda, Asst. Prof, Dayananda Sagar College of Engg, Blore. Please write to hareeshang@gmail.com for suggestions and criticisms.
Basic types of screw fasteners, Bolts of uniform
strength, I.S.O. Metric screw threads, Bolts under
tension, eccentrically loaded bolted joint in shear,
Eccentric load perpendicular and parallel to axis of
bolt, Eccentric load on circular base, design of Turn
Buckle.
The document discusses the design of helical springs. It defines what springs are and their objectives, such as cushioning shocks. It describes common spring materials like music wire and different types of springs like cylindrical helical and leaf springs. The document covers stress analysis and deflection analysis of helical compression springs. It provides the basic design procedure for determining spring dimensions given inputs like load and deflection.
Unit 3 Temporary and Permanent Joints.pptxCharunnath S V
This document discusses various types of temporary and permanent joints, including threaded fasteners, riveted joints, and welded joints. It provides details on different types of riveted joints, methods of riveting, types of threaded elements, and thread terminology. The document also covers topics such as bolted joints, failures in bolts, stresses on threaded fasteners, and problems involving eccentric loading conditions.
There are four main types of grinding machines: surface grinding machines, cylindrical grinding machines, internal grinding machines, and tool and cutter grinding machines. Surface grinding machines are classified by spindle orientation and table movement. Cylindrical grinding machines include plain, universal, and centerless types. Internal grinding machines include chucking, planetary, and centerless types. Tool and cutter grinding machines are used to manufacture or resharpen tools and cutters.
The document discusses measurement and metrology of screw threads. It begins with definitions of screw thread terminology such as major diameter, minor diameter, pitch, angle, and forms of threads. It then describes methods for measuring the major diameter, minor diameter, effective diameter, and pitch of screw threads. The key measurement methods discussed are using micrometers, pitch gauges, and a tool maker's microscope. The goal is to understand principles and techniques for measuring characteristics of screw threads.
This document provides a syllabus for a Machine Design course. The syllabus covers the design of simple machine elements, shafts, keys, couplings, elements under fluctuating loads, power screws, threaded joints, welded joints, and mechanical springs. The course aims to teach students how to identify failure modes, design various machine elements to withstand stresses, and design elements subjected to different loading conditions. The syllabus is divided into 6 units that will cover these various machine design topics. Required textbooks are also listed.
This document provides information on the course ME 8593-DESIGN OF MACHINE ELEMENTS. The objectives of the course are to familiarize students with the design process, principles of evaluating component shape and dimensions to satisfy requirements, use of standards and catalogs, and use of standard machine components. The textbook and reference materials are listed. The course will cover topics such as stresses in machine elements, shafts and couplings, joints, energy storing elements, and bearings.
Machine design is the process of creating or improving machines. It requires consideration of factors like the type and stresses of loads on the machine, the kinematics or motion of parts, selection of suitable materials, and determining the proper form and size of parts. Successful machine design draws on knowledge of mathematics, engineering mechanics, strength of materials, manufacturing processes, and other disciplines. The general procedure involves recognizing a need, synthesizing a mechanism design, analyzing stresses, selecting materials, designing elements, and modifying the design as needed before production. The document outlines the content of a machine design course, including sessions on mechanism dynamics, failure analysis, design of elements like flywheels and joints, and a design project.
The document provides an overview of the fundamentals of machine design course, including the objectives, syllabus, and key concepts covered. The main points are:
1. The course aims to introduce students to machine design fundamentals, material selection, and solving basic design problems. Key topics include modeling robot links and joints, computer graphics, and designing end-effectors.
2. The syllabus covers topics such as engineering design processes, material selection factors, standards and codes, stress analysis, failure theories, and static and dynamic load considerations.
3. Key concepts taught are stress-strain analysis, factors of safety, strength and efficiency principles, and manufacturing and ergonomic considerations in the design process.
The document provides an introduction to machine design, outlining key requirements for machine elements such as strength, rigidity, and wear resistance. It discusses the mechanical engineering design process and various topics that will be covered in the machine design course, including design of elements against static and fluctuating loads, shaft keys and couplings, threaded joints, and mechanical springs. Standardization, aesthetics, and other considerations in machine design are also introduced.
This document outlines a course on mechanical design that covers fundamentals like the design process, stress analysis, joint design, springs, and ergonomics. It lists textbooks for the course and specifies an assessment breakdown of assignments, tests, and a final exam. The first chapter discusses the mechanical design process, mechanical properties of materials, design factors, stress concentrations, and provides examples of calculating allowable stress.
The document outlines the course contents for a machine design course. The course covers fundamentals of design like stress analysis and factors of safety. It also covers topics like joints, springs, ergonomics and materials selection. The course assessments include assignments, tests and a final exam. Key chapters discussed include fundamentals of design, stress concentrations, mechanical properties and factors of safety. The chapter on fundamentals of design describes the mechanical design process and considerations like loads, stresses, materials and manufacturing processes.
The document describes the design and analysis of a leadscrew. It includes objectives to design the leadscrew based on applied forces and stresses, model the component in PRO/E, and analyze it in ANSYS. It covers terminology, applications, screw jack design, modeling steps in PRO/E, static structural analysis in ANSYS under different loads, and results for deformation, shear stress, strain, and normal stress. The analysis found the leadscrew does not fail under the applied forces and shows satisfactory results for reduced load values.
DESIGN OF MACHINE ELEMENTS NOTES.PDF SHARESelvaBabu2
This document provides an overview of the course Design of Machine Elements. It discusses key considerations in machine design like the design process, classifications of designs, factors influencing design like material selection and stresses, and general design principles. The course covers topics like design of shafts and couplings, fasteners, springs, bearings and flywheels. It aims to impart knowledge of engineering mechanics, strength of materials and other topics to successfully design machine components.
1 a. Introduction design of machine elementDr.R. SELVAM
The document discusses machine design and standardization. It defines machine design as designing machine elements and arranging them optimally to perform useful work. It categorizes machine design into adaptive, development, and new design. Standardization is defined as obligatory norms for product characteristics like materials and dimensions to reduce variety. Standards include company, national, and international standards for materials, shapes, fits, tolerances, surface finish, and testing. Benefits of standardization include inventory control, interchangeability, improved quality, and safety.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
This document provides an introduction to mechanical engineering. It discusses what mechanical engineers do, including designing machines and systems, manufacturing, testing, maintenance, and more. Some key areas mechanical engineers work in are energy, transportation, manufacturing, and healthcare. The document outlines the mechanical engineering education process and typical career paths, noting mechanical engineers work in a wide variety of industries. It emphasizes mechanical engineering involves problem solving, applying math and science concepts, and benefits society through technological innovation.
Topology Optimization for Additive Manufacturing as an Enabler for Robotic Ar...piyushsingh376
The current research is intended to minimize the mass of T shaped joint by using lattice structure and topological optimization tool.
The stresses, deformation, safety factor of generic and optimized design is evaluated on the basis of these mentioned parameters. The findings have shown that topological optimization method is best as compared to lattice structure method for weight minimization.
This document summarizes the design, static analysis, and modal analysis of a connecting rod for a four-stroke spark ignition engine using three different materials: structural steel, titanium alloy, and aluminum alloy. The connecting rod was modeled in SolidWorks and analyzed in ANSYS to determine von Mises stresses, shear stresses, deformation, natural frequencies, and safety factors. The results showed that titanium alloy had the highest safety factor and was therefore the best material for withstanding the loads on the connecting rod, though it was heavier than aluminum alloy. Aluminum alloy was the second best choice. Structural steel performed the poorest with the highest weight.
Term Project presentation Robotic Gripper design project - Copy.pptxravilearnsonline
The document describes the design of a gripper for a robot to grasp a spare tire assembly from a rack and insert it into the trunk of a 2018 Honda Civic. A pneumatic gripper design was selected using a decision tree and Bayesian model. The gripper uses standard parts to reduce costs and maintenance. Forces acting on the gripper were analyzed using simulations. The optimized design is lightweight, low cost, durable and can accommodate various spare tire sizes.
Mechanical design and taboos of mechanical designJasmineHL
The document discusses the process of mechanical design. It begins with planning, which involves investigating requirements and constraints. This is followed by scheme design, where multiple solutions are considered. Technical design then refines the best scheme, determining part dimensions and drawings. Finally, technical documents are prepared. Computer tools now aid in optimization, analysis, and virtual prototyping during mechanical design. The goal is to design reliable, high-quality machines through a scientific process.
This document outlines the syllabus for a course on Design of Machine Elements - I. It includes information on textbooks, reference books, modules, and topics to be covered. The course will cover the design process, analysis of forces on machine components, design for static strength, failure theories, stress concentration, and fundamentals of mechanical engineering design. It will consist of 3 hours of lectures and 2 hours of tutorials per week over 10 weeks. The first module will cover the introduction to design process, phases of design, engineering materials and properties, manufacturing processes, codes and standards, loading conditions, stresses, and design for static strength.
summarized all important and required information for all designers how belongs to Automobile and mechanical engineering.
we consist software for drafting, modeling, analysis etc.
selection of material, prototyping & design posses.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
1. ME 8593-DESIGN OF
MACHINE ELEMENTS
Unit 1 - STEADY STRESSES AND
VARIABLE STRESSES IN MACHINE
MEMBERS
DEPARTMENT OF MECHANICAL ENGINEERING
2. Textbooks and Reference
TEXT BOOKS:
• 1. Bhandari V, “Design of Machine Elements”, 4th Edition, Tata McGraw-
Hill Book Co, 2016.
• 2. Joseph Shigley, Charles Mischke, Richard Budynas and Keith Nisbett “
• Mechanical Engineering Design”, 9th Edition, Tata McGraw-Hill, 2011
REFERENCES:
• 1. Alfred Hall, Halowenko, A and Laughlin, H., “Machine Design”, Tata McGraw-Hill
BookCo.(Schaum’s Outline), 2010
• 2. Ansel Ugural, “Mechanical Design – An Integral Approach", 1st Edition, Tata McGraw-Hill
Book Co, 2003.
• 3. P.C. Gope, “Machine Design – Fundamental and Application”, PHI learning private ltd, New
Delhi, 2012.
• 4. R.B. Patel, “Design of Machine Elements”, MacMillan Publishers India P Ltd., Tech-Max
Educational resources, 2011.
• 5. Robert C. Juvinall and Kurt M. Marshek, “Fundamentals of Machine Design”, 4th Edition,
Wiley, 2005
• 6. Sundararajamoorthy T. V. Shanmugam .N, “Machine Design”, Anuradha Publications,
Chennai, 2015.
3. UNIT I STEADY STRESSES AND VARIABLE
STRESSES IN MACHINE MEMBERS
• Introduction to the design process - factors
influencing machine design, selection of materials
based on mechanical properties - Preferred
numbers, fits and tolerances – Direct, Bending
and torsional stress equations – Impact and shock
loading – calculation of principle stresses for
various load combinations, eccentric loading –
curved beams – crane hook and ‘C’ frame- Factor
of safety - theories of failure – Design based on
strength and stiffness – stress concentration –
Design for variable loading.
4. STEADY STRESSES AND
VARIABLE STRESSES IN
MACHINE MEMBERS
Design
Process
fits and
tolerances
Direct,
Impact
Stress
Principle
stresses
(PSG 7.2)
Curved
Beams
(PSG 6.2,
6.3)
Theories
of Failure
(PSG 7.3)
Stress
Concentration
(PSG 7.6)
o Red colored – Most important, Orange colored – Next most important, Black – important topics
9. Is an Engine, a Machine?
• All engines can be called machines, but not
all machines can be called engines.
• Engine is basically a prime mover which
generates power using some fuel i.e. diesel,
petrol etc. A machine needs power to do work
which must be created by hand, engine or
electric motor. Engine could be a component
of machine.
15. Machine Design
• Machine design is defined as the use of
scientific principles, technical information
& imagination in the description of a
machine or a mechanical system to
perform specific functions with maximum
economy & efficiency.
• Machine Design is defined as the creation
of new design (Machines) or improving the
exist one.
16. •Mathematics
•Engineering Mechanics
•Strength of Materials
e
e
g
• Math matics
• Engin ering Mechanics
• Stren th of Materials
• Workshop Processes
• Engineering Drawing
What is the basic knowledge required for Machine Design?
•Mathematics
•Engineering Mechanics
•Strength of Materials
•Workshop Processes
•Engineering Drawing
• Mechanics of Machines
• Mechanics of Materials
• Fluid Mechanics & Thermodynamics
16
17. 4 C’s in Design Process
• Creativity
• Complexity
• Choice
• Compromise
18. Classifications of Machine Design
1. Adaptive design (Old design)
2. Development design (Modification in old design)
3. New design (Creating a new design)
a. Rational Design (Mathematical formulae)
b. Empirical design (Empirical formulae – Practice & Past
Experience)
c. Industrial design (Production aspect)
d. Optimum design (Best design)
e. System design
f. Element design
g. Computer Aided design
19. Basic Requirement of Machine Element
(DESIGN CONSIDERATIONS IN MACHINE DESIGN)
Factors influencing Machine Design
• Strength and Stiffness
• Type of Load and stresses
• Rigidity
• Maintenance
• Flexibility
• Size and shape
• Stiffness
• Reliability
• Kinematics of machine
• Safety of operation
• Weight
• Manufacturing considerations
• Selection of Materials
• Corrosion of Materials
• Friction and wear
• Frictional resistance and lubrication
• Life
• Assembly considerations
• Conformance to standards
• Vibrations
• Thermal considerations
• Workshop facilities
• Ergonomics
• Aesthetics
• Cost
• Noise
• Environmental factors
21. General procedure in Machine Design
Detailed drawing
Need or aim
Synthesis
Analysis of the FORCES
Material selection
Design of elements
Recognize and specify the problem
Select the mechanism that would give the desired
motion and form the basic model with a sketch etc
Determine the stresses and thereby the sizes of
components s.t. failure or deformation does not
occur
Modify sizes to ease construction & reduce overall cost
Modification
Production
23. Material Selection
• The best material is one which will serve the
desired purpose at minimum costs
• Factors Considered while selecting the Material
– Availability
– Cost
– Mechanical properties: Strength, Hardness,
Toughness, Ductility, Malleabilty, etc.,
– Manufacturing considerations – Shaping, Machining,
Joinimg, surface finishing, FoS, Assembly cost
24. Factor of safety
• Is used to provide a design margin over the
theoretical design capacity to allow for
uncertainty in the design process.
– In the calculations,
– Material strengths,
– Manufacturing process
• FoS = Strength of the component (Max load)
Load on the component (Actual load)
28. AU Questions on the completed topic
• Explain various phases in Design using a flow
diagram and enumerate the factors
influencing the machine design.
(APR/MAY 2013)
• Write short notes on preferred numbers, fits
and types of fits. (APR/MAY 2012)
• What is meant by Hole basis system and Shaft
basis system? Which one is preferred and
why? (APR/MAY 2013)
29. UNIT I STEADY STRESSES AND VARIABLE
STRESSES IN MACHINE MEMBERS
• Introduction to the design process - factors
influencing machine design, selection of materials
based on mechanical properties - Preferred
numbers, fits and tolerances – Direct, Bending
and torsional stress equations – Impact and shock
loading – calculation of principle stresses for
various load combinations, eccentric loading –
curved beams – crane hook and ‘C’ frame- Factor
of safety - theories of failure – Design based on
strength and stiffness – stress concentration –
Design for variable loading.
30. STEADY STRESSES AND
VARIABLE STRESSES IN
MACHINE MEMBERS
Design
Process
Fits and
tolerances
Direct,
Impact
Stress
Principle
stresses
(PSG 7.2)
Curved
Beams
(PSG 6.2,
6.3)
Theories
of Failure
(PSG 7.3)
Stress
Concentration
(PSG 7.6)
o Red colored – Most important, Orange colored – Next most important, Black – important topics
31. Preferred Numbers (PSG 3.1 to 3.6)
• These are the kind of numbers derived from
geometric series, including the integral
powers of 10.
• Developed by French military engineer Charles
Reynard in 1877 – Standardisation.
• Basic series : R5, R10, R20, R40, R80
• R5(
5
10), R10 (
10
10), R20 (
20
10), R40
(
40
10), R80 (
80
10). (Note: This will be multiplied by ‘a’ – variable)
32. Applications of R Series
• R5 – Hydraulic cylinder capacities, Tolerance
grades in ISO standards.
• R10 – Hoisting – cranes, dia of wire ropes.
• R20 – Thickness of sheet metals, dia of wires
of helical springs, machine tool design
• R40 – Hydraulic cylinder diameters.
34. Allowance
• It is an intentional difference between the
maximum material limits of mating parts.
• It is the difference between the basic
dimensions of the mating parts.
• The allowance may be positive or negative.
When the shaft size is less than the hole size,
then the allowance is positive
• When the shaft size is greater than the hole
size, then the allowance is negative.
35. Tolerance
• It is the difference between the upper limit and
lower limit of a dimension. In other words, it is
the maximum permissible variation in a
dimension. The tolerance may be unilateral or
bilateral. When all the tolerance is allowed on
one side of the nominal size, e.g.,
• It is said to be unilateral system of tolerance
• The unilateral system is mostly used in industries
as it permits changing the tolerance value while
still retaining the same allowance or type of fit.
36. Tolerance
• When the tolerance is allowed on both sides
of the nominal size , then it is said to be
bilateral system of tolerance.
• In this case +0.002 is the upper limit and
-0.002 is the lower limit.
37.
38.
39. Lower limit = 27. 8
0.2
Upper limit = 28 . 2
Hole
Terminology for Limits and Fits Cont.
Tolerance
zone
Tolerance :Tolerance is the difference between maximum limit of size and minimum
limit of size.
Ø28
(Basic)
Zero line
40. CLASSIFICATION OF FITS
Clearance fit
Interference fit
Transition fit
Fit is the relationship that exists between two mating
parts, a hole and shaft with respect to their
dimensional difference before assembly. Three types
of fit are given hereunder
41. Clearance Fit
Clearance Fit : In clearance Fit shaft is
always smaller than the hole. A positive
allowance exists between the largest
possible shaft and smallest possible hole.
Minimum Clearance : It is the
difference between the
maximum size of shaft and
minimum size of hole.
Maximum clearance: It is the
difference between the
minimum size of the shaft and
the maximum size of hole
Hole basis
Shaft Basis
42. A
B
Fig. 1.2 Clearance Fit
Min hole – Max Shaft = + ve – clearance fit.
Fit with positive clearance between the hole and the shaft.
CLEARANCE FIT
43. Fit Cont.
Interference Fit: It is also
called Press or force fit, In
this fit shaft is always larger
than the hole
MAX interference: it is the
difference between the
maximum size of hole and the
minimum size of shaft prior to
assembly
Minimum Interference: It is the
difference between the
minimum size of the hole and
the maximum size of the shaft
prior to assembly.
Shaft
Hole
44. INTERFERENCE FIT
Fit with negative clearance between the hole and the shaft.
Fig. 1.3 Interference Fit
Max hole – Min Shaft = - ve – interferance fit
45. Fit Cont.
Transition Fit: it is called
sliding Fit . It occurs when the
resulting fit due to the
variations in size of the male
and female components due
to their tolerance, varies
between clearance and
interference fits. The
tolerance zones of shaft and
hole overlap
Shaft
Hole
46. TRANSITION FIT
Fit established when the dimensions of the hole are such that there exists
either a positive clearance or a negative clearance when the shaft is fitted
into the hole.
B
47. SYSTEMS OF FITS
HOLE BASIS SYSTEM: the hole is constant in diameter and various types
of fits are obtained by suitably varying the limits of the shaft.
SHAFT BASIS SYSTEM: the shaft is constant in diameter and various
types of fits are obtained by suitably varying the limits of the hole.
48. Fig. 1.5 Hole Basis System
Clearance Fit
B
Interference Fit
C
HOLE BASIS SYSTEM
Single hole, whose lower deviation is zero.
Minimum limit of the hole will be equal to its basic size.
49. HOLE BASIS SYSTEM - Design Example
Requirement
Hole basic size - 20 mm diameter.
Clearance of - 0.100 mm.
Hole tolerance - 0.025 mm.
Shaft tolerance - 0.050 mm.
Minimum limit of the hole is Ø 20 mm.
Maximum limit of the shaft = Lower limit of the hole –
Minimum clearance
= Ø 19.900 mm
Design
50. Minimum limit of the shaft = Maximum limit of the shaft –
Tolerance on the shaft.
= Ø 19. 850 mm.
Shaft
Max. limit = Ø 19.900 mm.
Min. limit = Ø 19. 850 mm.
Maximum limit of the hole = Maximum limit of the hole +
Tolerance on the hole.
= Ø 20. 025 mm.
Hole
Max. limit = Ø 20.025 m.
Min. limit = Ø 20. 000 mm.
51. Why the Hole Basis System is Preferred?
Holes are produced by drilling, boring, reaming, broaching, etc.,
Shafts are either turned or ground.
Shaft basis system - Holes of different sizes are required,
(requires tools of different types and
sizes).
Hole basis system - Only one tool is required, to
produce the hole and the shaft can
be machined to any desired size.
52. Hole Basis System Shaft Basis System
Hole is keep constant and the
shaft diameter is varied
The basic size of the hole is taken
as the low limit
The high limit of the size of the
hole and the two limits of size of
the shaft are selected to give the
desired fit
The actual size of the hole is
within the tolerance limit.
In this system Hole gets the letter
H and the shaft gets letter o decide
the position of tolerance
Shaft is kept constant and the hole
diameter is varied.
The basic size of the shaft is taken as one
of the limits(maximum) of size of shaft
The other limit of size of the shaft and the
two limits of hole are then selected to give
the desired fit
The actual size of a hole that is within the
tolerance limits is always less than the
basic size.
In this system Shaft gets the letter h and
the hole gets different letter o decide the
position of the tolerance zone to obtain
desired fit
53. Fundamental deviation for Shafts
(IT – Std tolerance)
For holes
• Upper deviation ES
• Lower deviation EI
• EI = ES – IT (OR) ES = EI + IT
For Shaft
• Upper deviation es
• Lower deviation ei
• ei = es – IT (or) es = ei + IT
54. POINTS SHOULD REMEMBER Before
SOLVING PROBLEMS (For the whole Unit)
• All the parameters should convert to mm.
• The answer value should be in the unit of
mm.
55. Problem on Tolerance
• A shaft of 40mm dia having tolerance grade of
5. Calculate the IT tolerance value by using the
equation and Table.
56. A shaft of 40mm dia having tolerance grade of 5. Calculate the IT
tolerance value by using the equation and Table.
• Given:
– D = 40 mm
– Tolerance Grade = 5
• To Find:
– IT tolerance by both table and equation
59. A shaft of 40mm dia having tolerance grade of 5.
PSG data book page no: 3.6 (For Equation)
• i = 0.45 3√D + 0.001D
• Where D = √D1D2
• D1 = Max dia from PSG data book Pg no.3.3
• D2 = Min dia from PSG data book Pg no.3.3
• D1 = 50
• D2 = 30
• Hence D = √D1D2 = √30 * 50 = 38.73mm
60. A shaft of 40mm dia having tolerance grade of 5.
PSG data book page no: 3.6 (For Equation)
• i = 0.45 3√D + 0.001D
• i = 0.45 3√ 38.73 + 0.001 (38.73)
• i = 1.5612 microns
• From PSG data book page no: 3.6
• For IT grade value 5 the tolerance value is 7i
• Hence 7 I = 7 x 1.5612= 10.9285 microns ≈ 11
microns
62. AU Questions on the completed topic
• (i) Discuss in detail about the factors
influencing machine design. (OR) What are the
factors influencing machine design? Explain it.
• (ii) Write short notes on the following:
• Interchangeability
• Tolerance
• Allowance
(APR/MAY 2012)(MAY/JUNE 2014)
63. STEADY STRESSES AND
VARIABLE STRESSES IN
MACHINE MEMBERS
Design
Process
Fits and
tolerances
Direct,
Impact
Stress
Principle
stresses
(PSG 7.2)
Curved
Beams
(PSG 6.2,
6.3)
Theories
of Failure
(PSG 7.3)
Stress
Concentration
(PSG 7.6)
o Red colored – Most important, Orange colored – Next most important, Black – important topics
64. UNIT I STEADY STRESSES AND VARIABLE
STRESSES IN MACHINE MEMBERS
• Introduction to the design process - factors
influencing machine design, selection of materials
based on mechanical properties - Preferred
numbers, fits and tolerances
• Direct, Bending and torsional stress equations –
Impact and shock loading – calculation of
principle stresses for various load combinations,
eccentric loading – curved beams – crane hook
and ‘C’ frame- Factor of safety - theories of failure
– Design based on strength and stiffness – stress
concentration – Design for variable loading.
65. TYPE OF LOADS AND STRESSES IN
REAL- TIME APPLICATIONS
Steady loads
• Dead loads
• Live loads
Variable loads
• Shock loads (suddenly)
• Impact loads (applied
with some velocity)
axial (tension-
compression) ,
flexural (bending)
torsion(twisting) in nature.
Thermal Loading
66. Static Load
Time
Stress
F and P are applied and remain constant
Stress Ratio, R = 1.0
A static (steady) load is a
stationary force or couple
(applied to a member) that
does not change in magnitude,
point of application, and
direction.
67. • An element subjected to Dynamic loads
(tensile and compressive stresses involved)
Continuous total load reversal over time
Dynamic Load:
68. Stress is dependent on the load characteristics.
Strength is an inherent property of the material.
•.
Factor of safety depends on
Type of material
How controllable are environment conditions
Type of loading and the degree of certainty
with which the stresses are calculated
Type of application
Failure can mean a part
•has separated into two or more pieces; (brittle)
•has become permanently distorted, thus ruining its geometry; (ductile)
•has had its function compromised
Strength Vs Stress
Factor of safety = Strength / Stress = S / σ
70. Allowable stress
. . . While designing a component, it must be
ensured that the maximum stress that may be induced
during working life, do not exceed a certain safe limit . .
Such a safe limiting stress is known as allowable,
permissible or design stress
71. TENSILE STRESS:
When a body is subjected to two equal and
opposite axial pulling forces, F - F as shown in
Fig.
the stress induced at any section A – A of the body
is known as tensile stress and the corresponding
strain, the tensile strain (the ratio of total
elongation, 8 to the original length, l).
72. When a body is subjected to two equal and opposite
axial pushing forces, F
COMPRESSIVE STRESS:
73. When a body is subjected to two equal and
opposite forces acting tangentially across the
resisting section, as a result of which the body
tends to shear off the section, then the stress
induced is called shear stress.
SHEAR STRESS:
Single shearing of a riveted joint.
74. the area resisting the shear off the rivet
Double shearing of a riveted joint.
75. Bending Stress
• 𝜎𝑏 =
𝑀𝑏
𝑍
• 𝑀𝑏 or M - Bending Moment
• Z =
I
𝑦
– Sectional Modulus (PSG 6.1)
76. Problem
• The piston of a reciprocating compressor has
a dia of 60mm. The max pressure on the
piston tall is 1.25MN/m2 (12.5 bar). Assuming
the gudgeon pin passing through the small
end of the connecting rod can be safely
loaded in shear upto 10 MN/m2. Cal the min
dia of the gudgeon pin.
77. The piston of a reciprocating compressor has a dia of 60mm. The max
pressure on the piston tall is 1.25MN/m2 (12.5 bar). Assuming the gudgeon
pin passing through the small end of the connecting rod can be safely loaded
in shear upto 10 MN/m2. Cal the min dia of the gudgeon pin.
Given:
• D = 60mm
• P = 1.25MN/m2
• = 1.25 N/mm2
• 𝜏 = 10 MN/m2
• = 10 N/mm2
To Find:
• Gudgeon pin dia, d
Hint:
1 MN/m2 = 1 N/mm2
(1 MN/m2 = 1 x 106 N/ 106mm)
78. D = 60mm; P = 1.25 N/mm2;
𝜏 = 10 N/mm2
• Solution:
• Piston area = D2/4 = 2,826 mm2
• Piston force = Pressure x Area
= 1.25 N/mm2 x 2,826 mm2
= 3,560.76 N
79. D = 60mm; P = 1.25 N/mm2;
𝜏 = 10 N/mm2
Solution:
• Gudgeon pin has double shear
• Hence, P = 2 x 𝜏 x Area
• 3,560.76 = 2 x 10 x ∏d2/4
• d = 15.06 mm
Result:
• Diameter of Gudgeon pin = 15.06mm
80.
81. Consider a straight beam subjected to a bending moment M
as shown in Fig.
The bending equation
is given by
82.
83. Problem
• A cantilever of span 500mm carries a vertical
downward load of 6kN at free end. Assume
the yield value is 350MPa and FoS is 3. Find
the economical section for the cantilever
among
• a) Circular cross section of dia “d”
• b) Rectangular section of depth “h” and width
“t” where h/t = 2
• c) ɪ section of depth 7t and flange width 5t
where t is thickness . Specify the dimension
and area.
84. A cantilever of span 500mm carries a vertical downward load of 6kN at free
end. Assume the yield value is 350MPa and FoS is 3. Find the economical
section for the cantilever among
a) Circular b) Rectangular c) ɪ section
Given data:
• Length, L = 500 mm
• Load, P = 6000 N
• σy = 350 N/mm2
• FoS, n = 3
To Find:
• Economical section among Circular,
rectangular and I section
86. L = 500 mm; P = 6000 N; σy = 350 N/mm2; FoS, n = 3
• Mb = P x L = 6000 x 500 = 3x106 N-mm
• Allowable stress, σb = σy / n = 350/3 = 116.67
N/mm2.
• a) Circular Section:
• Bending moment equation:
•
σb
𝑦
=
Mb
ɪ
σb
𝑑
=
Mb
ɪ
σ =
32Mb
πd3
• W.K.T, ɪ = πd4 / 64 (PSG 6.1) & y = d/2
87. Area for Circular rod
• d = 63.98 ≈ 64 mm
• Cross sectional area , A = πd2 / 4 = 3215.63 mm2
88. L = 500 mm; P = 6000 N; σy = 350
N/mm2; FoS, n = 3; σb = 116.67 N/mm2
b) Rectangular section:
• Given that h = 2t
• Mb = P x L = 6000 x 500 = 3x106 N-mm
• Bending moment equation:
•
σb
𝒚
=
Mb
ɪ
• Where y = h/2, ɪ = th3/12
(PSG 6.1)
t
89. Rectangular Section
• Now, σb = Mb x (h/2) / th3/12
• σb = Mb x (1/2) / th2/12
• σb = Mb / 2 t(2t)2/12
• σb = Mb x 6 / t(2t)2
• t3 = Mb x 6 / 4 x σb
• t3 = 3x 106 x 6 / 4 x 116.67 t = 33.78 ≈ 34
mm
91. ɪ section
• Given that depth is 7t and width is 5t
• ɪ = ɪ1 - ɪ2
• = b1 h1
3 / 12 - 2 x b2 h2
3 / 12
• = [5t (7t)3 – 2 x 2t (5t)3 ]/12
• ɪ = 1125t4 / 12
• Bending moment equation:
•
σb
𝑦
=
Mb
ɪ
• Where y = 3.5t (i.e., h/2)
7t
5t
1t
1t
5t
t
92. l = 500 mm; P = 6000 N; σy = 350
N/mm2; FoS, n = 3; σb = 116.67 N/mm2
• σb =
Y . Mb
ɪ
• 116.67 = 3.5t x 3x106 / 1125t4 /12
• t = 9.8 mm
• h = 7t = 68mm
• b = 5t = 49mm
• Area = b h – 2 * (b2 h2)
= (5t * 7t) – 2 * (2t * 5t)
Area = 1,593 mm2
93. Result
• Area of ɪ section = 1593 mm2
• Area of Rectangular section = 2313 mm2
• Area of Circular section = 3215 mm2
• Hence the economical section for cantilever
beam based on area is ɪ section.
• ɪ section is chosen.
94. AU Question on the completed topic
• 7) A cantilever beam of rectangular cross-section is used to support a
pulley as shown in Fig. 11a. The tension in the wire rope is 10 kN. The
beam is made of cast iron whose ultimate strength σut= 240 MPa and the
factor of safety is 3. The ratio of depth to width of cross-section is 2.
Determine the dimensions of the cross-section of the beam. (NOV/DEC
2020 AND April/May 2021)
95. Bearing Stress
A localised compressive stress at the surface of
contact between two members of a machine part,
that are relatively at rest is known as bearing stress or
crushing stress.
the bearing stress or crushing stress (stress at the surface of contact
between the rivet and a plate
96.
97. Impact Stress
• Stress produced in the member due
to load with impact or falling load is
known as Impact stress.
Where,
E – Young’s Mod
l – Bar length
l – Bar deformation
h – height through
which the load falls
98. Problem
• An unknown weight falls through 10mm on a
collar rigidly attached to the lower end of a
vertical bar 3m long and 600mm2 in section. If
the max instantaneous extension is known to
be 2mm. What is the corresponding stress and
the value of unknown weight. Take
E =200kN/mm2.
99. An unknown weight falls through 10mm on a collar rigidly attached to the
lower end of a vertical bar 3m long and 600mm2 in section. If the max
instantaneous extension is known to be 2mm. What is the corresponding
stress and the value of unknown weight. Take E =200kN/mm2.
Given:
• h = 10mm
• l = 3m = 3000mm
• A = 600mm2
• l = 2 mm
• E =200 x 103 N/mm2
To Find :
W
100. h = 10mm; l = 3m = 3000mm; A = 600mm2
; l = 2 mm; E =200 x 103 N/mm2
Solution:
• E = l/ l E l/l =
• = 200 x 103 * 2 / 3000
• = 133.3 N/mm2
• = W/A [1 + 1 +
2ℎ𝐴𝐸
𝑊𝑙
]
• W = 6666.7 N
101. When a machine member is subjected to the action of
two equal and opposite couples acting in parallel planes
(or torque or twisting moment), then the machine
member is said to be subjected to torsion.
Torsional Shear Stress
103. AU Problem on Torsional equation
18) A hollow shaft is required to transmit 500 W
at 100 rpm. The maximum torque being 20%
greater than the mean. The shear stress is not to
exceed 65 MPa and twist in a length of 2 metres
not to exceed 1.2 degrees. Find the external and
internal diameter of the shaft, if the ratio of
internal to external diameter is 3/8. Take
modulus of rigidity as 84 GPa. (APR/MAY 2019)
104. STEADY STRESSES AND
VARIABLE STRESSES IN
MACHINE MEMBERS
Design
Process
Fits and
tolerances
Direct
(CSA),
Impact
Stress
Principle
stresses
(PSG 7.2)
Curved
Beams
(PSG 6.2,
6.3)
Theories
of Failure
(PSG 7.3)
Stress
Concentration
(PSG 7.6)
o Red colored – Most important, Orange colored – Next most important, Black – important topics
105. UNIT I STEADY STRESSES AND VARIABLE
STRESSES IN MACHINE MEMBERS
• Introduction to the design process - factors
influencing machine design, selection of materials
based on mechanical properties - Preferred
numbers, fits and tolerances
• Direct, Bending and torsional stress equations –
Impact and shock loading – calculation of
principle stresses for various load combinations,
eccentric loading – curved beams – crane hook
and ‘C’ frame- Factor of safety - theories of failure
– Design based on strength and stiffness – stress
concentration – Design for variable loading.
106. Principal stresses for various load
consideration
• Practically mechanical components are
subjected to several types of external loads
simultaneously.
• Principal stresses are the maximum and
minimum normal stresses on a particular
plane, well we can also determine extreme
values of normal stresses possible in the
material.
110. Approach to Principal Stresses
problems
1. Calculate Direct stress, 𝜎𝑑 =
𝑃𝑎
𝐴
2. Calculate Bending stress, 𝜎𝑏 =
32𝑀𝑏
𝜋𝑑3
3. Calculate Torsional Shear stress, 𝜏𝑥𝑦 =
16𝑀𝑡
𝜋𝑑3
4. If it is bending, 𝜎𝑥 = 𝜎𝑑 + 𝜎𝑏
If it is Compression, 𝜎𝑥 = 𝜎𝑑 − 𝜎𝑏
5. From PSG DB 7.2, find Max (use +ve) & Min (-ve)
Principal Stress and Shear Stress (Assume 𝜎𝑦 = 0)
111. Problem on Principal stresses
16) A circular shaft of 30mm dia is subjected to
an axial load, bending moment and twisting
moment as shown. Det the max principal stress,
min principal stress and maximum shear stress
at point A and B.
Axial/Direct Load
Bending Load
Torsion
114. • Now, PSG Data book page no 7.2 to find Max
principal stress, min principal stress and Shear
stress
115.
116.
117.
118. 16) A shaft, as shown in Figureis subjectedto a bendingload of 3kN, pure
torque of 1000 N-m and an axial pullingforce of 15 kN. Calculate the
stressesat A and B
Given :
W = 3 kN = 3000 N ;
T = 1000 N-m = 1 × 106 N-mm ;
P = 15 kN= 15 × 103 N ;
d = 50 mm;
Length (l) x= 250 mm
(APR/MAY 2010) (APR/MAY 2016)
119. This bending stress is tensile at point A and compressive at point B.
∴ Resultant tensile stress at point A
122. Problem
17) A crank shaft of 20mm dia is subjected to a
load of 10kN as shown. Det the max and min
principal stresses and max shear stress at the
crank shaft bearing.
123.
124.
125.
126.
127.
128. Q3.An overhang crank with pin and shaft is shown in Fig. 5.18. A tangential
load of 15 kN acts on the crank pin. Determine the maximum principal stress
and the maximum shear stress at the centre of the crankshaft bearing.
Given :
W = 15 kN = 15 × 103 N ;
d = 80 mm ;
y = 140 mm ;
l = 120 mm
129. Bending moment at the centre of the
crankshaft bearing,
M = W * l =
Torque transmitted at the axis of the shaft,
T = W × y =
132. AU Problems
• A hollow circular column of
external diameter 250 mm and
internal diameter 200 mm carries
a projecting bracket on which a
load of 20 kN rests as shown in
Fig. The centre of the load from
the centre of the column is 500
mm. Find the stresses at the
sides of the column. All
dimensions in mm. (NOV DEC
2016)
133. Approach to this problems
1. Calculate Direct stress, 𝜎𝑑 =
𝑃𝑎
𝐴
Where A = /4 (D2 – d2)
2. Calculate Bending stress, 𝜎𝑏 =
𝑀𝑏𝑦
𝐼
(Take I
from PSG 6.2)
3. If it is bending, 𝜎𝑥 = 𝜎𝑑 + 𝜎𝑏
If it is Compression, 𝜎𝑥 = 𝜎𝑑 − 𝜎𝑏
135. STEADY STRESSES AND
VARIABLE STRESSES IN
MACHINE MEMBERS
Design
Process
Fits and
tolerances
Direct,
Impact
Stress
Principle
stresses
(PSG 7.2)
Curved
Beams
(PSG 6.2,
6.3)
Theories
of Failure
(PSG 7.3)
Stress
Concentration
(PSG 7.6)
o Red colored – Most important, Orange colored – Next most important, Black – important topics
136. UNIT I STEADY STRESSES AND VARIABLE
STRESSES IN MACHINE MEMBERS
• Introduction to the design process - factors
influencing machine design, selection of materials
based on mechanical properties - Preferred
numbers, fits and tolerances
• Direct, Bending and torsional stress equations –
Impact and shock loading – calculation of
principle stresses for various load combinations,
eccentric loading – curved beams – crane hook
and ‘C’ frame- Factor of safety - theories of
failure – Design based on strength and stiffness –
stress concentration – Design for variable loading.
141. Approach to Curved beam problems
• Step 1: Find Direct Stress d = P/A
• Step 2: Find the bending stress bi = M .h/a.e.r
(Mostly for Inner fibre) – Find out other
parameters [PSG DB – 6.2]
– Step 2.1 : Various Radius: R, ri, ro, rn,
– Step 2.2 : Eccentricity : e, hi
– Step 2.3 : Moment Mb
• Either Load, diameter or max stress has to be
found
142. Problems on Curved Beams
• A C-shaped link of circular
section having dia 20mm is
loaded as shown. Det the
max stress in the link.
143. A C-shaped link of circular section having dia 20mm is
loaded as shown. Det the max stress in the link.
Given Data:
• Load, P = 1 kN
• Dia of circular rod, d = 20 mm
• Centroidal axis radius, R = 50mm
To find:
• Max Stress, max
144.
145.
146.
147.
148.
149. Problems on Curved Beam (Crane
Hooks)
• A trapezoidal cross section crane hook having
a yield strength of 380 N/mm2 is loaded as
shown below. Assume the FoS for hook
material is 3.5. Det the load carrying capacity.
150. A trapezoidal cross section crane hook having a yield strength of
380 N/mm2 is loaded as shown below. Assume the FoS for hook
material is 3.5. Det the load carrying capacity.
Given Data:
• Yield strength,
y = 380 N/mm2
• fs = 3.5
• Inner radius, ri = 45 mm
• For trapezoidal cross
section:
– bi = 80 mm
– bo = 25 mm
– h = 110 mm
To Find:
• Load carrying capacity, P
151.
152.
153. • Factor of safety is given in the problem
• WKT, FoS (n) = Yield stress/ allowable stress
154.
155. Problems on Curved Beams
• A S-link having circular cross
section is subjected to a load
of 2 KN shown. Dia of link is
30mm. Det the max tensile
stress and max shear stress of
the S-link.
156. A S-link having circular cross section is subjected to a
load of 2 KN shown. Dia of link is 30mm. Det the max
tensile stress and max shear stress of the S-link.
157.
158.
159.
160.
161.
162.
163.
164. Approach to Curved beam problems
• Step 1: Find Direct Stress d = P/A
• Step 2: Find the bending stress bi = M .h/a.e.r
(Mostly for Inner fibre) – Find out other
parameters [PSG DB – 6.2]
– Step 2.1 : Various Radius: R, ri, ro, rn,
– Step 2.2 : Eccentricity : e, hi
– Step 2.3 : Moment Mb
• Either Load, diameter or max stress has to be
found
165.
166. AU Problems on Curved Beams
• The C-frame of a 100 kN capacity press is
shown in Fig. The material of the frame is grey
cast iron FG 200 and the factor of safety is 3.
Determine the dimensions of the frame.
• (APR/MAY 2010) (APR/MAY 2018) (NOV/DEC
2018)
167. AU Problems on Curved Beams
• A punch press of capacity 50 KN has a c-frame
of ‘T’ cross section as shown in the fig. The
Tensile strength of material is 350 MPa. Take
FoS as 3.5. Determine the dimensions of C-
frame. (NOV 2021)
168. AU Problems on Curved Beams
• A link shaped in the form of a letter S is made
up of 30 mm diameter bar, as shown in figure
Determine the maximum tensile stress and
maximum shear stress in the link.
• (APR MAY 2017)
169. AU Problems on Curved Beams
• (i) The frame of a punch press is shown in fig. Find the
stresses at the inner and outer surface at section X-X of
the frame, if W = 5000 N.
(MAY/JUNE 2014)
• (ii) What is factor of safety? List the factors to be
considered while deciding the factor of safety.
(MAY/JUNE 2014)
170. AU Problems on Curved Beams
• Determine the stress at point A and B split ring
shown in fig. If a compressive force = 20 kN is
applied point ‘C’. (APR/MAY 2018) (PART C)
171. AU Problems on Curved Beams
• A wall bracket with a rectangular cross-section is
shown in Fig. The depth of the cross-section is
twice of the width. The force P acting on the
bracket at 600 to the vertical is 5 kN. The material
of the bracket is grey cast iron FG 200 and the
factor of safety is 3.5. Determine the dimensions
of the cross-section of the bracket. Assume
maximum normal stress theory of failure.
(APR/MAY 2018)
172.
173. STEADY STRESSES AND
VARIABLE STRESSES IN
MACHINE MEMBERS
Design
Process
Fits and
tolerances
Direct,
Impact
Stress
Principle
stresses
(PSG 7.2)
Curved
Beams
(PSG 6.2,
6.3)
Theories
of Failure
(PSG 7.3)
Stress
Concentration
(PSG 7.6)
o Red colored – Most important, Orange colored – Next most important, Black – important topics
174. UNIT I STEADY STRESSES AND VARIABLE
STRESSES IN MACHINE MEMBERS
• Introduction to the design process - factors
influencing machine design, selection of materials
based on mechanical properties - Preferred
numbers, fits and tolerances
• Direct, Bending and torsional stress equations –
Impact and shock loading – calculation of
principle stresses for various load combinations,
eccentric loading – curved beams – crane hook
and ‘C’ frame- Factor of safety - theories of
failure – Design based on strength and stiffness
– stress concentration – Design for variable
loading.
178. Maximum Principal Stress Theory
• When the maximum
principal stress induced in
a material under complex
load condition exceeds the
maximum normal strength
in a simple tension test the
material fails.
• Good for brittle materials.
179. Maximum Shear Stress Theory
• When the maximum
shear strength in actual
case exceeds maximum
allowable shear stress in
simple tension test the
material case.
• Good for ductile materials
180. Maximum Principal Strain Theory
• When the maximum
normal strain in actual
case is more than
maximum normal strain
occurred in simple
tension test case the
material fails.
• Not recommended
181. Maximum Strain Energy Density Theory
• When the total strain
energy in actual case
exceeds the total strain
energy in simple tension
test at the time of
failure, the material
fails.
• Good for ductile
material
182. Maximum Distortion Energy Density
Theory
• When the shear strain
energy in the actual case
exceeds shear strain
energy in simple tension
test at the time of failure
the material fails.
• Highly recommended
185. Approaches for
Problem on Theories of Failure
1. Calculate Bending moment and Torsional
Moment
2. Calculate Stresses: 𝜎𝑥, 𝜏𝑥𝑦
3. Calculate Principle stresses (PSG 7.2)
4. Use any theory of failure to the required
dimension. (PSG 7.3)
196. Part C AU Problems
• A shaft which has a diameter of 30 mm is
subjected to an axial tension load of 15kN and a
torque of 400 Nm. In addition to these, there is a
bending moment of 300 Nm on the shaft. The
Shaft is made of steel having the properties of Su
= 780MPa ad Sy = 600 MPa.
• Neglecting the column action, determine the FOS
using
• Distortion energy theory of failure
• Shear Stress theory of failure (NOV/DEC 2019)
Note: Assume Poisson’s Ratio = 0.25 to 0.3
197. AU Problems
• A rod is subjected to axial tensile load of 20
KN and torsional load of 10 KN-m. Determine
the diameter of rod according to
• (1) Rankine’s theory
• (2) St. Venant’s theory
• (3) Trasca theory.
• Take factor of safety = 2.5, Poisson’s ratio =
0.25, s y =300N /mm2 . (7) (NOV 2021)
198. AU Problems
• A solid circular shaft of diameter 45 mm
is loaded by bending moment 650 Nm,
torque 900 Nm and an axial tensile force
of 30 kN. The shaft material is ductile
with yield strength of 280 MPa.
Determine the factor of safety according
to Maximum principal stress, Tresca and
Von misses theories of failure. (APR MAY
2017)
199. AU Problems
• A bolt is subjected to a direct load of 25 kN and
shear load of 15 kN. Considering theories of
failure. Determine a suitable size of the bolt (PSG
5.49) if the material of the bolt is C15 having 200
N/mm2 yield strength. Assume F.O.S. as 2 and
also give your comments.
• i) Maximum normal stress theory
• ii) Maximum shear stress theory
• iii) Von mises theory. (NOV/DEC 2017)
208. Stress Concentration
• A stress concentration (often called
stress raisers or stress risers) is a location
in an object where stress is concentrated.
• An object is strongest when force is
evenly distributed over its area, so a
reduction in area, e.g., caused by a crack,
results in a localized increase in stress.
209. Stress Concentration
• The existence of irregularities or discontinuities,
such as holes, grooves, or notches, in a part
increase the magnitude of stresses significantly in
the immediate vicinity of the discontinuity.
Fatigue failure mostly originates from such
places.
• Stress concentration factor need not be used with
ductile materials when they are subjected to only
static loads, because (local) yielding will relieve
the stress concentration.
210.
211.
212. Techniques to reduce stress
concentration
• Avoiding sharp corners and only using rounded
corners with maximum radii.
• Sanding and polishing surfaces to remove any notches
or defects that occur during forming and processing.
• Lowering the stiffness of straight load-bearing
segments.
• Placing notches and threads in low-stress areas.
• Provide fillets
• Use of multiple holes instead of single holes
• Undercutting the shoulder parts.
213. Techniques to reduce stress
concentration
• Additional Notches and Holes in Tension Member
• Fillet Radius, Undercutting and Notch for Member in Bending
214. Techniques to reduce stress
concentration
• Drilling Additional Holes for Shaft
• Reduction of Stress Concentration in Threaded Members
215. Notch Sensitivity
• The degree to which actual stress
concentration effect compares with the
theoretical stress concentration effect.
• The values of q are between zero and unity.
It is evident that if q=0, then Kf =1, and the
material has no sensitivity to notches at all.
On the other hand if q=1, then Kf = Kt, and
the material has full notch sensitivity.
216. Factors for Notch sensitivity
• Notch radius
• Material
• Size of the component
• Type of loading
218. Design Consideration &
Calculation of K
• For design consideration, the result obtained
depends on the following: In case of a circular
hole in a bar we consider the ratio 𝒓 / 𝒅. For
the fillet the ratio is 𝒓 / 𝒅 𝑎𝑛𝑑 𝑫 / 𝒅.
• To find the value of K we need to find use
graph.
226. Endurance Limit
• Max value of stress that the standard
specimen can sustain for a infinite number of
cycles (10^6 cycles) without failure.
• Stress ratio =
𝜎𝑚𝑎𝑥
𝜎𝑚𝑖𝑛
246. AU Problems
• A component machined from a plate made of 45C8
(σu= 650 MPa) as shown in Fig. 11b. It is subjected to a
completely reversed axial force of 100 kN. The
reliability factor, kc = 0.897; factor of safety = 2. The
size factor, kb = 0.8, surface finish factor, ka = 0.76.
determine the thickness of the plate, for infinite life, if
the notch sensitivity factor, q = 0.8. (NOV/DEC 2020
AND April/May 2021)
247. AU Problems
• A shaft of diameter 'd' is subjected to a torque
varying between 900 Nm to 1800 Nm.
Assuming a factor of safety 2 and a stress
concentration factor of 1.2, find the diameter
of the shaft. Take au = 650 N/mm2, ay = 480
N/mm2, Size factor B = 0.85 and surface finish
factor C = 0.5. (NOV/DEC 2014)
248. AU Problems
• A cantilever beam made of cold drawn carbon steel of
circular cross section as shown in fig., is subjected to a load
which varies from –F to 3 F. Determine the maximum load
that this member can withstand for an indefinite life using a
factor of safety as 2. The theoretical stress concentration
factor is 1.42 and the notch sensitivity is 0.9. Assume the
following values:
– Ultimate stress = 550 MPa
– Yield stress = 470 MPa
– Endurance limit = 275 MPa
– Size factor = 0.85
• Surface finish factor = 0.89.
• (APR/MAY 2011)
249. PART C AU Problems
• A machine component is subjected to a flexural
stress which fluctuates between +300 MN/m2
and -150MN/m2. Determine the value of
minimum ultimate strength according to
• 1) Gerber relation
• 2) Modified Goodman relation and
• 3) Soderberg relation.
• Take yield strength =0.55 Ultimate strength;
Endurance strength =0.5 Ultimate strength; and
factor of safety =2. (NOV/DEC 2017)
250. AU Problems
• A 40 mm diameter shaft is made from carbon steel
having ultimate tensile strength of 600 MPa. It is
subjected to a torque which fluctuates between 1500 Nm
to -900 Nm. Using Soderberg method, calculate the
factor of safety. Assume suitable values for any other
data needed. (APR/MAY 2019)
251. AU Problems
• A steel cantilever is 200 mm long. It is subjected to an axial load which
varies from 150 N (compression) to 450 N (tension) and also a transverse
load at its free end which varies from 80 N up to 120 N down. The
cantilever is of circular cross-section. It is of diameter 2d for the first 50
mm and of diameter d for the remaining length. Determine its diameter
taking a factor of safety of 2. Assume the following values :
– Yield stress = 330 MPa
– Endurance limit in reversed loading = 300 MPa
– Correction factors = 0.7 in reversed axial loading = 1.0 in reversed
bending
– Stress concentration factor = 1.44 for bending = 1.64 for axial loading
– Size effect factor = 0.85
– Surface effect factor = 0.90
– Notch sensitivity index = 0.90 (APR/MAY 2016)
252. AU Problems
• A cantilever rod of length 120mm with circular
section is subjected to a cyclic transverse load;
varying from -100 N to 300N at its free end.
Determine the diameter “d” of the rod, by
(i) Goodman method and (ii) Soderberg method
using the following data.
Factor of safety =2; Theoretical stress
concentration factor=1.4; Notch sensitivity
factor=0.9; ultimate strength =550MPa; Yield
Strength =320MPa; Endurance limit =275MPa;
size correction factor=0.85; Surface correction
factor=0.9. (NOV/DEC 2015)
253. AU Problems
• A cantilever rod of length 120mm with circular
section is subjected to a cyclic transverse load;
varying from -100 N to 300N at its free end.
Determine the diameter “d” of the rod, by (i)
Goodman method and (ii) Soderberg method
using the following data. Factor of safety =2;
Theoretical stress concentration factor=1.4;
Notch sensitivity factor=0.9; ultimate strength
=550MPa; Yield Strength =320MPa; Endurance
limit =275MPa; size correction factor=0.85;
Surface correction factor=0.9. (NOV/DEC 2015)
254. AU Problems
• A shaft of diameter 'd' is subjected to a
torque varying between 900 Nm to 1800
Nm. Assuming a factor of safety 2 and a
stress concentration factor of 1.2, find
the diameter of the shaft. Take au = 650
N/mm2, ay = 480 N/mm2, Size factor B =
0.85 and surface finish factor C = 0.5.
(NOV/DEC 2014)
255. AU Problems
• Define Stress concentration, Give some
methods of reducing stress concentration.
(NOV/DEC 2011)
• What is the difference betwaeen Gerber curve
and Soderberg and Goodman lines?
(APR/MAY 2013)
256. STEADY STRESSES AND
VARIABLE STRESSES IN
MACHINE MEMBERS
Design
Process
fits and
tolerances
Impact
Stress
Principle
stresses
(PSG 7.2)
Curved
Beams
(PSG 6.2,
6.3)
Theories
of Failure
(PSG 7.3)
Stress
Concentration
(PSG 7.6)
o Red colored – Most important, Orange colored – Next most important, Black – important topics