3. Chapter Objectives
• Describe the phases or stages in systems
engineering and the new product
development process
• Recognize product liability and safety
issues
• Recognize the significance of reliability and
other design factors
4. Engineering Design
• Design is the activity that best describes the engineer. To
design is to create something that has never existed
before, either as a solution to a new problem or as a
better solution to a problem solved previously.
• Design is the central purpose of engineering. It begins
with the recognition of a need and the conception of an
idea to meet that need.
• It proceeds with the definition of the problem, continues
with a program of directed research and development,
and leads to the construction and evaluation of a
prototype.
5.
6. Nature of Engineering Design
Information:
• Statement of the problem
• Design standards
• Design methods
Information:
• Drawings
• Specifications
• Financial estimates
• Written reports
• Oral presentations
7. Systems Engineering/
New Product Development
The design of a complex engineered system, from the
realization of a need through production to engineering
support in use is known as systems engineering (especially
with military or space systems) or as new product
development (with commercial systems)
systems engineering is an engineering discipline whose
responsibility is creating and executing an interdisciplinary
process to ensure that the customer and stakeholder’s
needs are satisfied in a high quality, trustworthy, cost
efficient, and schedule compliant manner throughout a
system’s entire life cycle
8. Tasks of systems
engineering
• State the problem
• Investigate alternatives
• Model the system
• Integrate
• Launch the system
• Assess performance
• Reevaluate
• Disposal Stage
9. Concurrent (Simultaneous)
Engineering
• In traditional engineering, a relatively short
time was spent defining the product.
• A relatively long time is spent designing
the product, and a surprisingly longer time
is often spent redesigning the product.
• The key to shortening the overall design
time is to better define the product and
better document the design process.
10. Concurrent (Simultaneous)
Engineering
• A new approach is now applied to the engineering
design philosophy to create products that are
better, less expensive, and more quickly brought to
market.
• This trend reunites technical and nontechnical
disciplines such as engineering, marketing, and
accounting.
• This approach to reduce time-to-market has
become widely adopted under the name concurrent
(or simultaneous) engineering
11. Traditional Product Development
• System Level Design
• Subsystem Design
• Component Design
• Manufacturing Process Concept Development
• Manufacturing Process Development
• Delivery Development
• Service Development
• Delivery
13. Definition of Concurrent Engineering
A systematic approach to the integrated, concurrent
design of products and their related processes,
including manufacture and support.
This approach is intended to cause the developer,
from the outset, to consider all elements of the
product lifecycle from concept through disposal,
including quality control, cost, scheduling, user
requirements. (Inst. For Defense Analysis)
14. Advantages of Concurrent
Engineering
The set of methods, techniques, and practices that:
• Cause significant consideration within the design
phases of factors from later in the life cycle;
• Produce, along with the product design, the design
of processes to be employed later in the life of the
product;
• Facilitate the reduction of the time required to
translate the design into distributed products; and
• Enhance the ability of products to satisfy users'
expectations and needs.
15. Concurrent (Simultaneous)
Engineering
• Benefits of concurrent engineering (CE) include
• 30 to 70 percent less development time,
• 65 to 90 percent fewer engineering changes,
• 20 to 90 percent less time-to-market,
• 200 to 600 percent higher quality, and
• 20 to 110 percent higher white-collar productivity.
16. Functions for faster product
development and fewer changes
• Colocate key functional disciplines.
• Organize cross-functional teams.
• Use computer-aided design (CAD) software.
• Conduct thorough design reviews at design concept and
definition stages.
• Involve key disciplines, especially manufacturing, early in
development.
• Prepare properly for CE implementation.
• Allow for a CE learning curve.
• Implement CE in small, manageable bites.
18. Phases in Systems Engineering /
New Product Development (NSPE)
• Conceptual
• Technical feasibility
• Development
• Commercial validation and production preparation
• Full-scale production
• Product support
19. • Approval to expend the resources / agreement on
the work to be accomplished.
• Accomplishment of the work
• Compile the results: designs and specifications,
analyses and reports, and a proposed plan for
conducting the following phase if one is
recommended.
– To cancel the development,
– To go back (recycle) and do more work in the present
phase; or
– To proceed with the next phase.
Tasks Within Each Phases of Systems
Eng. / New Product Development
20. Conceptual stage
• Statement of the design problem, clearly
defining what the desired intended
accomplishment of the desired product
• Key functions
• Performance characteristics
• Constraints
• Criteria of judging the design quality
21. Conceptual stage
• Musts: requirements that must be met
• Must nots: constraints defining what the system
must not be or do
• Wants: features that would significantly enhance
the value of the solution but are not mandatory
(to which an additional, even less compelling
category of "nice to have" is often added)
• Don't wants: characteristics that reduce the
value of the solution
23. Conceptual stage
(Kano’s Model)
Product is non-conformant
Product conforms to std.
Product is unsafe
Product is safe to use
Function not provided
Normal function
Missing instruction
Clear instruction
Broken parts
All parts work
Scratches, blemishes
Smooth Surface
Dissatisfiers
Expected Quality
25. Conceptual stage
(Kano’s Model)
Examples of Delighters
• Sony Walkman
• 3M Post-it
• Cup Holder
• One-touch recording
• Redial button on telephone
• Graphic User Interface (GUI)
26. Results from Conceptual stage
• A set of functional requirements
• Identification of the potential barriers to
development, manufacturing, and marketing the
proposed product.
• Test-of-principle model to reduce technical
uncertainties
• Order-of-magnitude economic analyses and
• Preliminary market surveys to reduce financial
uncertainty.
28. Technical feasibility stage
The objectives of this stage are
• To confirm the target performance of the new
product through experimentation and/or accepted
engineering analysis and
• To ascertain that there are no technical or
economic barriers to implementation
29. Technical feasibility stage
• Subsystem identification
• Trade-off studies
• System integration
• Interface definition
• Preliminary breadboard-level testing
• Subsystem and system design requirements (reliability,
safety, maintainability, and environmental impact).
• Development of preliminary test plans, production
methods, maintenance and logistic concepts, and
marketing plans.
• Preliminary estimation of the life-cycle cost of the system.
• Preparation of a proposal for the development stage
31. Development stage
(Build-test-fix-retest sequences)
The objective of this stage is
• To make the needed improvements in materials,
designs and processes and
• To confirm that the product will perform as
specified by constructing and testing engineering
prototypes or pilot processes.
32. Commercial validation and
Production preparation stage
The objective of this stage is to develop the
manufacturing techniques and establish test
market validity of the new product.
• Selecting manufacturing procedures, production
tools and technology, installation and start-up
plans for the manufacturing process, and
• Selecting vendors for purchased materials,
components, and subsystems.
Reproduction prototypes
33. Full-scale production stage
• Final design drawings, specifications, flow charts,
and procedures are completed for manufacture
and assembly of all components and subsystems
of the product, as well as for the production facility.
• Quality control procedures and reliability standards
are established
• Contracts made with suppliers
• Procedures established for product distribution and
support.
• Manufacturing facilities are constructed
• Continuous process improvement (kaizen)
34. Product support stage
• Technical manuals for product installation,
operation, and maintenance
• Training programs for customer personnel
• Technical supports
• Warranty services
• Repair parts and replacement consumables must
be manufactured and distributed
• New procedures for operation and maintenance
• Improved parts for retrofit
• Notification of product recall for safety reasons
35. Disposal stage
• Every product causes waste during manufacture,
while in use, and at the end of useful life that can
create disposal problems.
• The time to begin asking, "how do we get rid of
this" is in the early stages of product or process
design.
36. CALS
• "Computer Aided Logistics Support," then
• "Computer-aided Acquisition and Logistics
Support,"
• "Continuous Acquisition and Life-Cycle Support,"
(1993, DoD)
• "Commerce At Light Speed" (U.S. industry)
37. Purposes of CALS
To enable more effective generation,
management, and use of digital data
supporting the life cycle of a product
through the use of international standards,
business process change, and advanced
technology application.
38. CALS
Electronic storage, transmission, and retrieval of
digital data
• Between engineers representing the several
design stages,
• Between organization functions such as marketing,
design, manufacturing, and product support, and
• Between cooperating organizations such as
customer and supplier.
39. Control Systems in Design
• In creating a complex system, hundreds or thousands of
engineers, technicians, and other workers may be involved
in creating designs, reviewing them, manufacturing or
constructing in accordance with them, or inspecting to
assure that what has been made agrees with what was
specified.
• Design changes are inevitable.
• Control systems for drawing/design release and
configuration management are essential to assure that
everyone knows what the official design (configuration) is at
any instant, while change can be managed effectively.
40. Control Systems in Design
• Drawing/Design Release
– Version Control
– Product Data Management (PDM)
• Configuration (Design Criteria) Management
– Functional baseline (at end of conceptual stage)
– Allocated baseline (at end of validation stage)
– Product baseline (at end of development stage)
• Design Review
– Conceptual design review
– System design review
– System/software design review
– Critical design review
41. Special Considerations in Design
• Product liability
• Safety
• Reliability
• Maintainability
• Availability
• Ergonomics
• Producibility
42. History of Product Liability
• Caveat emptor (let the buyer beware)
• “Privity of contract” (Direct contractual relationship)
• 1916, MacPherson v. Buick (No need for direct contract)
• Plaintiff must prove negligence
• 1960, Hernington v. Bloomfield Motors, implied
warranty
• 1984, Greenman v. Yuba Power Product Strict
Liability
• Absolute liability: “A manufacturer could be held strictly
liable for failure to warn of a product hazard, even if the
hazard was scientifically unknowable at the time of the
manufacture and sale of the product.”
43. Reducing Liability
• Include safety as a primary specification for product
design.
• Use standard, proven materials and components.
• Subject the design to thorough analysis and testing.
• Employ a formal design review process in which
safety is emphasized.
• Specify proven manufacturing methods.
• Assure an effective, independent quality control
and inspection process.
• Be sure that there are warning labels on the
product where necessary.
44. Reducing Liability
• Supply clear and unambiguous instructions for
installation and use.
• Establish a traceable system of distribution, with
warranty cards, against the possibility of product
recall.
• Institute an effective failure reporting and analysis
system, with timely redesign and retrofit as
appropriate.
• Document all product safety precautions, actions,
and decisions through the product life cycle.
45. Designing for Reliability
Definition of Reliability:
• Reliability is the probability that a system
• Will demonstrate specified performance
• For a stated period of time
• When operated under specified
conditions.
46. Reliability Measures
• Reliability
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• Failure PDF (probability density function):
• Failure or hazard rate:
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• Simple Parallel Model
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48. Simple Reliability Models
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51. Maintainability
• Maintainability is the probability that a
failed system
• Will be restored to specified performance
• Within a stated period of time
• When maintained under specified
conditions.
53. Availability
• Inherent Availability (considers only corrective
maintenance)
Ai = MTBF / (MTBF+MTTR)
• Operational Availability (considers both preventive
& corrective maintenance)
Ao = MTBM / (MTBM+MDT)
MTBM: Mean Time Between Maintenance
MDT: Mean Down Time
MTTR: Mean Time To Repair
MTBF: Mean Time Between Failure (1/)
BIT: Build-In Test
54. Other Considerations
• Human Factors Engineering (Ergonomics)
• Standardization
– Set of specifications for parts, materials, or
processes intended to achieve uniformity,
efficiency, and a specified quality.
• Producibility
