Residual stresses influence the behavior of mechanical components, plastic materials, composite materials and can modify the structural, the dimensional stability, the fatigue and the fracture resistance of components.
Residual stresses can be caused by the following main factors:
non-uniform heating or cooling of a component during manufacturing and fabricating processes (e.g., casting, welding, molding, heat treatment)
machining processes to remove shavings or plastic deformation (e.g., turning and forging)
through or surface heat treatments (e.g., tempering, welding or grinding)
sand-blasting or shot-peening.
The hole-drilling method allows accurate experimental stress analyses at moderate costs by drilling a small hole (typically 1.8 – 2.0 mm) which changes the initial deformation allowing redistribution of the residual stresses locked in a material.
Fracture mechanics CTOD Crack Tip Opening DisplacementDavalsab M.L
Fracture Mechanics .Whilst the Crack Tip Opening Displacement (CTOD) test was developed for the characterisation of metals it has also been used to determine the toughness of non-metallics such as weldable plastics.
The CTOD test is one such fracture toughness test that is used when some plastic deformation can occur prior to failure - this allows the tip of a crack to stretch and open, hence 'tip opening displacement
Diseno en ingenieria mecanica de Shigley - 8th ---HDes
descarga el contenido completo de aqui http://paralafakyoumecanismos.blogspot.com.ar/2014/08/libro-para-mecanismos-y-elementos-de.html
Fatigue is important as it is the largest cause of failure in metals, estimated to comprise approximately 90% of all metallic failures; polymers and ceramics are also susceptible to this type of failure.
Fracture mechanics CTOD Crack Tip Opening DisplacementDavalsab M.L
Fracture Mechanics .Whilst the Crack Tip Opening Displacement (CTOD) test was developed for the characterisation of metals it has also been used to determine the toughness of non-metallics such as weldable plastics.
The CTOD test is one such fracture toughness test that is used when some plastic deformation can occur prior to failure - this allows the tip of a crack to stretch and open, hence 'tip opening displacement
Diseno en ingenieria mecanica de Shigley - 8th ---HDes
descarga el contenido completo de aqui http://paralafakyoumecanismos.blogspot.com.ar/2014/08/libro-para-mecanismos-y-elementos-de.html
Fatigue is important as it is the largest cause of failure in metals, estimated to comprise approximately 90% of all metallic failures; polymers and ceramics are also susceptible to this type of failure.
Strain Measurement Techniques for Composites TestingInstron
This presentation looks at traditional methods of strain measurement and the latest developments in automatic contacting and non-contacting extensometers.
An Experimental Study of the Effect of Control Parameters on the Surface Roug...IOSR Journals
Surface quality is one of the specified manufacturer requirements for machined parts. There are
many parameters that have an effect on surface roughness, but those are difficult to quantify adequately in
finish turning operation such as cutting speed, feed rate, and depth of cut are known to have a large impact on
surface quality. The Taguchi method is one of the statistical tools, to investigate influence of surface roughness
by cutting parameters such as cutting speed, feed and depth of cut. The Taguchi process helps to select or to
determine the optimum cutting conditions for turning process. Many researchers developed many mathematical
models to optimize the cutting parameters to get lowest surface roughness by turning process. The Taguchi
design of experiments was used for optimizing quality and performance output of manufacturing processes.
Vibration control of newly designed Tool and Tool-Holder for internal treadi...IJMER
Machining processes are manufacturing methods for ensuring processing quality, usually within
relatively short periods and at low cost. Several machining parameters, such as cutting speed, feed rate, work
piece material, and cutting tool geometry have significant effects on the process quality. Many researchers have
studied the impact of these factors. The cutting tool overhang affects the surface quality, especially during the
internal turning process, but this has not been reviewed much [9].
SKZ112 Crush Tester is used to do the Ring Crush test (RCT), Edge Crush Test (ECT), Flat Crush Test (FCT), Pin Adhesive Strength Test (PAT), and Paper Tube Compress Test .
We also have the accessories for its each test.
Threats to mobile devices are more prevalent and increasing in scope and complexity. Users of mobile devices desire to take full advantage of the features
available on those devices, but many of the features provide convenience and capability but sacrifice security. This best practices guide outlines steps the users can take to better protect personal devices and information.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Dr. Sean Tan, Head of Data Science, Changi Airport Group
Discover how Changi Airport Group (CAG) leverages graph technologies and generative AI to revolutionize their search capabilities. This session delves into the unique search needs of CAG’s diverse passengers and customers, showcasing how graph data structures enhance the accuracy and relevance of AI-generated search results, mitigating the risk of “hallucinations” and improving the overall customer journey.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
GridMate - End to end testing is a critical piece to ensure quality and avoid...ThomasParaiso2
End to end testing is a critical piece to ensure quality and avoid regressions. In this session, we share our journey building an E2E testing pipeline for GridMate components (LWC and Aura) using Cypress, JSForce, FakerJS…
GridMate - End to end testing is a critical piece to ensure quality and avoid...
Residual stress hole drilling
1. Via Delle Calandre 63
50041 Calenzano (Florence) – Italy
Tel: +39.055.8826-302 – Fax: -303
www.sintechnology.com
info@sintechnology.com
RESIDUAL STRESS MEASUREMENTS BY HOLE
DRILLING ACCORDING TO ASTM E837 STANDARD
2. • What are residual stresses
• Residual stress causes
• RS measuring methods with strain gages
• The hole-drilling strain-gage method
• The standard ASTM E837
• The instrument used for the measurements
• Typical application fields
• Typical measurement results
2Residual Stress Hole Drilling
PRESENTATION CONTENTS
3. All stresses that occur in the materials, also without the application of any external load,
are termed residual stresses
Residual stresses influence a mechanical component’s behaviour as they:
Affect structural and dimensional stability
Reduce fatigue strength and crack resistance
Encourage surface crack growth
3
What are residual stresses
Residual stresses therefore limit load
capacity and safety of mechanical
components during operation
Residual Stress Hole Drilling
4. 4
Residual stress causes
Machining process (turning)
Heat treatments (quenching) Surface treatments (shot peening)
Fabrication process (forging, welding)
Residual stresses can be caused by several main factors:
Residual Stress Hole Drilling
6. The hole-drilling strain-gage method is the most widely used method for
measuring residual stresses, for several reasons:
6
The hole-drilling strain-gage method
• Very simple
• Low cost of the machine (and of the test when using an automatic system)
• Possibility to elaborate the results up to at least 1mm in a very fast way
• High availability of strain gages and accessories for the measurement
• Compliant to ASTM E837, the only complete standard on RS
measurements available in the world
• Availability of AUTOMATIC MACHINE with very high resolution and
accuracy thanks to the complete control of all the measurement parameters
Residual Stress Hole Drilling
7. The hole-drilling strain-gage method consists in drilling a small hole (approx.
1.8 mm x 2.0 mm) into the centre of a 3-element strain rosette with suitable drill
bits and a special air turbine (400,000 RPM)
7
The hole changes the initial strain allowing redistribution of the
residual stresses originally existing in the material
Φ 1.8
mm
2 mm
The hole-drilling strain-gage method
Residual Stress Hole Drilling
8. 8
The hole-drilling strain-gage method is the only method for calculating residual stress
that is STANDARDIZED at world level (ASTM E837)
The first version of this standard dates back to 1995, the latest upgrade is available from
the end of 2013
Standard ASTM E837 specifies:
The number of drilling increments required
The numerical coefficients for determining the value of residual stresses
The data processing method
The measurement-related uncertainty
Hole-drilling strain-gage method to ASTM E837
Residual Stress Hole Drilling
9. THROUGH HOLE
Drilling depth: entire thickness
Stresses are assumed to be uniform
Acquisition of a set of 3 strain values
once the through hole is completed
9
INTERMEDIATE HOLE
Approximate results
The elaboration of the test result is
outside the scope of the ASTM E837-13
standard
THROUGH HOLE - THIN WORKPIECE
Workpiece thickness < 0.2·DGAGE (std. 1mm)
stresses are considered uniform over
the drilling depth
Hole-drilling strain-gage method to ASTM E837-13
Different types of holes, based on the workpiece thickness:
Residual Stress Hole Drilling
INTERMEDIATE HOLE
Workpiece thickness between 0.2·DGAGE e DGAGE (std. between 1mm and 5mm)
10. UNIFORM STRESSES
Drilling depth: 0.2 · DGAGE (std 1mm)
Stress value over the drilling depth
10 drilling steps of 0.02 · DGAGE (std
0.1 mm)
10
NOT UNIFORM STRESSES
Drilling depth: 0.2 · DGAGE (std 1mm)
Residual stress pattern over the drilling depth
20 drilling steps of 0.01 · DGAGE (std 0.05 mm)
Evolution of the “old” Integral Method
BLIND HOLE (Typical) – THICK WORKPIECE
Workpiece thickness > DGAGE (std. 5mm)
Hole-drilling strain-gage method to ASTM E837
Residual Stress Hole Drilling
A “uniform stress” calculation is appropriate when prior information is available, for
example, based on workpiece geometry or processing procedure.
Another purpose of doing a uniform stress calculation is to determine a representative
size of the residual stresses that are present.
11. 11
The MTS3000 system is the only fully AUTOMATIC and portable instrument in the
world for determining residual stress by the hole-drilling strain-gage method
The MTS3000 system consists of:
A mechanical setup housing the optical system and drilling system
An electronic control unit
A digital strain gage amplifier
Control and back-calculation software
Residual Stress Hole Drilling
The instrument used for the measurements
13. 13
Higher repeatability of measurement
Higher hole drilling accuracy
Shorter testing time
Fully compliant to ASTM E837 standard
HIGHER PRODUCTIVITY REDUCTION IN COSTS
The instrument: main advantages
Chief advantages in using
an AUTOMATIC system:
Residual Stress Hole Drilling
14. 14
The MTS3000 system can be used to determine residual stresses on a wide variety of
materials, such as:
Standard metals (e.g. Steel, Aluminum, Cast iron)
Non-standard metals (e.g. Titanium, High Tensile Steels)
Plastics (e.g. ABS, Polycarbonate)
Composites
CHOICE OF CONFIGURATION
CHOICE OF CUTTING AND
RECORDING PARAMETERS
CHOICE OF TYPE OF CUTTER
Air turbine (standard)
Electric motor (plastics, composites)
Feed rate
Rotational speed
Delay time
Tungsten carbide
Tungsten carbide with coatings
Diamond
The instrument: fields of application
Residual Stress Hole Drilling
15. 15
Hole drilling: typical application fields
Residual Stress Hole Drilling
• In 95% of the cases, the stresses are NOT uniform with the depth
• Generally, it’s difficult to predict the residual stress value of a component BUT…
• …In some typical application fields, it’s possible to have typical measurement results
- Typical on-site measurements -
• It’s difficult to measure residual stresses without a suitable machine because of the lower
precision of these instrument in the detection of the starting point and of the step/total
depth: this situation can lead to big errors in the post-elaboration of the results