At this year’s ASIP 2023 Conference in Denver, CO, ESRD provided a 2-hour training course titled “Enhancements in StressCheck v12.0 for DaDT Analysis of 3D Fastened Connections”, presented a technical paper titled “Experimental Validation of DTA Modeling of Bonded Wing Skin Repairs“, and passed out 3D printed F-35 and C-130 models at our booth inside the Gaylord Rockies Resort & Conference Center. The models were a big hit — look out for some new aircraft next year!

Conference Snapshot

ESRD’s Brent Lancaster, Patrick Goulding, and Brian Lockwood spent the week chatting with ASIP attendees and meeting many enthusiastic StressCheck users. The ASIP Conference has become an exciting platform for demonstrating many strong use cases of StressCheck spanning the ASIP community, with around a dozen technical presentations utilizing our technology for their DaDT analyses. We are honored to be such a prominent part of this event and to have so many talented and loyal users in this industry.

We would like to extend our sincerest gratitude to all those who attended Brent’s training, Brian’s technical paper presentation, and/or stopped by our booth to say hello to us. In addition, this was Patrick’s first ASIP Conference and he was thrilled to have the opportunity to meet you all. We really enjoy getting the chance to see you each year and we’re already looking forward to attending ASIP 2024 in Austin, TX.

ASIP 2023 Training Materials Available

On Monday, November 27th, Brent had the pleasure of providing a training course to a large group of attentive ASIP engineers on Enhancements in StressCheck v12.0 for DaDT Analysis of 3D Fastened Connections. We were thrilled with the level of interest and engagement, and the opportunity to present the latest in StressCheck. Thanks to those who attended the training course in person (as well as virtually)!

If you are interested in this topic, you can download Brent’s training presentation (in PowerPoint show or PDF format) and watch the video demo via the below link (note: you must be a registered user to view the training materials):

We are looking forward to receiving your feedback on the training course presentation, as well as your ideas for ASIP 2024 training course topics.

ASIP 2023 Technical Paper Presentation Available

On Thursday, November 30th, Brian had the honor of presenting his technical paper “Experimental Validation of DTA Modeling of Bonded Wing Skin Repairs” to a strong audience of engaged ASIP attendees. The paper was a collaboration between ESRD, AP/ES (Dr. Scott Prost-Domasky) and USAF AFMC WRALC/ENC (Laura Pawlikowski), and continued their project discussed in last year’s presentation (“DTA of Bonded Repairs on the Wing Skin of the C130 Using Finite Elements“) by providing experimental testing data to validate their simulation results.

If you are interested in this topic, you can view Brian’s technical paper presentation (in PowerPoint show or PDF format) via the below link (note: you must be a registered user to view the training materials):

Preview StressCheck v12.0!

Would you like to schedule a preview demonstration of the new features in StressCheck v12?

We would be happy to walk you through the exciting updates to the user interface design, model navigation and visualization tools, and enhanced meshing features.

ESRD, Inc. will be exhibiting, presenting a technical paper (on DTA of bonded repairs) and providing a 2-hour training course in person and virtually at the ASIP Conference 2023 in Denver, CO from November 27-November 30, 2023.  We hope you will drop by our technical presentation, training course and/or booth to check out the latest ESRD developments!

ESRD’s Training Course

A 2-hour training course titled “Enhancements in StressCheck v12.0 for DaDT Analysis of 3D Fastened Joints” will be held Monday, November 27th from 10:00 AM – 12:00 PM MST by ESRD’s Brent Lancaster.  The course description is as follows:

As more DaDT and service life analysis (SLA) engineers look to incorporate the influence of assembly multi-body contact, fastener hole propping and/or fastener load transfer into their beta factor and/or stress intensity factor (SIF) predictions, it is imperative that the numerical simulation of these effects on 3D fracture mechanics parameters can be ascertained without inflicting cumbersome modeling workflows, endless meshing cycles, and high computational costs on the end user. This training course will outline proposed methodologies, guidelines and best practices for ESRD’s StressCheck Professional finite element analysis (FEA) software to perform efficient and accurate DaDT analysis of flawed 3D fastened connections and multi-body contact assemblies, including enhanced automeshing and SIF extraction techniques now available in StressCheck v12.0. In addition, several live demonstrations of technology will be performed for representative use cases.

In this 2-hour training course, we will focus on the following topics:

• StressCheck’s FEA technology implementation for the modeling, meshing and analysis of arbitrarily shaped 3D crack geometries, with and without the local effects of multi-body contact.
• Strategies for automatic meshing of 3D cracks with high-aspect ratio, 3D-solid pentahedral and hexahedral elements to support high-quality SIF extractions at any location on the crack front.
• New StressCheck v12.0 method to support multi-body contact assembly meshing, auto-detection of contact regions, and automatic assignment of contact pairs for 3D solid bodies.

The training course content will be based on concepts from the following resources, available on ESRD’s Resource Library and online documentation:

• ASIP 2018 Training – Modeling Fastened Connections: Hierarchic Approaches Discussion and Demo
• Helpful Hints and Tips: 3D Stiffened Lug Stress + Crack SIF Analyses
• Helpful Hints and Tips: Interference Fit Bushing + SIFs
• StressCheck Demo: Part-Thru Crack SIFs for Stiffened Lug
• StressCheck Tutorial: 3D Elliptical Part-Thru Crack with Multi-Body Contact
• StressCheck Tutorial: Filled vs Open Hole SIF Comparison for 3D Offset Hole

ESRD’s Technical Presentation

A 30-minute technical presentation titled “Experimental Validation of DTA Modeling of Bonded Wing Skin Repairs” and authored by Mr. Brian Lockwood (ESRD), Ms. Laura Pawlikowski (Warner Robins ALC) and Dr. Scott Prost-Domasky (AP/ES) will be presented by Brian Lockwood on Thursday, November 30th at 10:30 AM MST.

As the principal investigator on this USAF SBIR-funded project, Brian will be presenting an update to his work so far in utilizing StressCheck’s finite element analysis implementation to assess the effectiveness of bonded skin repairs on the C-130 center wing. The technical presentation description is as follows:

This presentation is a follow-up to ESRD’s 2022 ASIP presentation titled “DTA of Bonded Repairs on the Wing Skin of the C-130 Using Finite Elements.” That presentation explored a robust method for finite element analysis of bonded skin repairs from the perspective of both static strength and fatigue crack growth. The proposed analysis methodology was presented in a comparative sense, examining a number of criteria in the skin in an undamaged state, a damaged state and a repaired state, in order to allow the analyst to make an assessment of repair effectiveness without detailed knowledge of either the exact boundary conditions of the problem, or of the intricacies of the model itself. One of the criteria for a patch to be deemed effective is that the fatigue life of the skin be at or above that of the pristine configuration.

Given the sparse nature of research on the topic of crack growth under bonded repair patches, ESRD partnered with AP/ES to conduct an experimental program to investigate in detail how a small initial flaw propagates in the aluminum skin under a titanium repair up through failure. Experiments were performed alongside blind predictions of life and crack morphology using ESRD’s research tool, CPAT. Additionally, statistical analysis was performed to assess confidence in the predictions. Given the aleatory uncertainty associated with the available crack growth data for the specimen material, it was important that predictions of fatigue life be accompanied by a confidence level when comparing them with experimental outcomes. Because most of the crack propagation occurred under the repair, a marker band spectrum was used during the test and the crack-cycle data was constructed from fractographic examination. The experimental program covered three specimen configurations:

• Undamaged skin with a surface crack or a corner crack at a hole.
• Skin with a grindout (to remove hypothetical corrosion damage) and either a surface crack at the bottom of the grindout or a corner crack at a hole located at the center of the grindout.
• Same as previous configuration, but including a bonded titanium repair.

Experimental and predicted results will be presented.

ESRD’s Exhibit Booth

ESRD can be found at Booth 5 and will have several staff members available to chat, provide demonstrations, troubleshoot issues (StressCheck Clinic), and answer questions about our training course, our technical presentation, our software products and our composite repair solutions.

We’ll be handing out some fun giveaways at our booth! Stop by early to chat with us and grab one!

Participating ESRD Staff

Contact information for ESRD staff participating in ASIP Conference 2023 is as follows:

• Mr. Brent Lancaster – brent.lancaster@esrd.com
• Mr. Brian Lockwood – brian.lockwood@esrd.com
• Mr. Patrick Goulding – patrick.goulding@esrd.com

ESRD, Inc. will be exhibiting, presenting a technical paper (on DTA of bonded repairs) and providing a 2-hour training course in person and virtually at the ASIP Conference 2022 in Phoenix, AZ from November 28-December 1, 2022.  We hope you will drop by our technical presentation, training course and/or booth to check out the latest ESRD developments!

ESRD’s Training Course

A 2-hour training course titled “Best Practices for the Modeling & Analysis of Bonded Doubler Repairs” will be held Monday, November 28th from 10:00 AM – 12:00 PM local time by ESRD’s Brent Lancaster.  The course description is as follows:

Current methodologies for modeling and analysis of bonded repair patch designs for application to damaged sections of aircraft wing skin can be computationally expensive and difficult to implement in practice, relying instead on accumulated practical experience to determine the effectiveness of a given repair design. These methods, although effective, require a knowledge base acquired over many years of experience making sustainment organizations vulnerable to gaps in knowledge between newer members and more seasoned experts.

This training course will outline proposed methodologies, guidelines and best practices for utilizing ESRD’s StressCheck Professional finite element analysis (FEA) software to parametrically model, analyze and assess the effectiveness of composite or metallic bonded repair patch designs and variations. The effectiveness of repairs regarding static strength and damage tolerance will be addressed. In addition, strategies for efficient solution verification and hierarchic modeling approaches of 3D repair patches will be explored, and a set of representative demonstrations of technology will be provided.

In this 2-hour training course, we will focus on the following topics:

• StressCheck’s FEA technology implementation enabling modeling of very thin domains, including adhesive layers with 3D-solid elements.
• Best practices and guidelines for modeling and analyzing 3D bonded repair doubler variations (e.g. racetrack/rectangular, circular/elliptical, tapered, metallic, ply-by-ply, homogenized, etc.) for circular cutouts and grindouts.
• Performing “what if?” logic-driven studies of a digital 3D bonded repair handbook solution via StressCheck API-powered Engineering Simulation App, in which user-defined input data is passed from Python or Excel VBA to StressCheck Professional to perform scripted “on-the-fly” model adjustments and repair-oriented computations.

The training course content will be based on concepts from the following resources, available on ESRD’s Resource Library and online documentation:

• A System for Simulation Governance of Engineered Repairs of Composite Aircraft Structures
• Bonded Composite Repair Patch for Cracked Hole (Video)
• Laminated Composite Repair Patch Part I – Geometry & Meshing (Video)
• Laminated Composite Repair Patch Part II – Materials, BC’s & Results
• Laminated Composite Repair Patch Part III – Geometric Nonlinear Analysis

ESRD’s Technical Presentation

A 30-minute technical presentation titled “DTA of Bonded Repairs on the Wing Skin of the C-130 Using Finite Elements” and authored by Mr. Brian Lockwood (ESRD), Mr. Ryan Patterson (Warner Robins ALC) and Dr. Scott Prost-Domasky (AP/ES) will be presented by Brian Lockwood on Thursday, December 1st at 3:30 PM local time.

As the principal investigator on this USAF SBIR-funded project, Brian will be presenting his work so far utilizing StressCheck’s finite element analysis implementation to assess the effectiveness of bonded skin repairs on the C-130 center wing. The technical presentation description is as follows:

Current methodologies for the design and application of repairs to damaged sections of aircraft wing skin can be lacking in analytical support, relying instead on accumulated practical experience to determine the effectiveness of a given patch design. These methods are, by their nature, effective, being based on observation, but inefficient, requiring a knowledge base acquired over years of experience. This can make sustainment organizations inflexible and vulnerable to gaps in knowledge between newer members and more seasoned experts. This approach is also problematic in its potential for wasted effort and material, applying repairs that may be more intensive than is required for a given situation.

These problems can all be addressed by the introduction of an accessible, robust analysis methodology cast in the form of an Engineering Simulation Application for the verification of a repair’s performance qualities prior to an actual aircraft application. The finite element method is ideally suited to provide an analysis procedure for this type of problems that can be used by analysts with widely varying degrees of expertise both in numerical simulation and bonded repair application. This presentation will outline a proposed methodology for utilizing finite element analysis to assess the effectiveness of a given bonded repair.

ESRD’s Exhibit Booth

ESRD can be found at Booth 12 and will have several staff members available to chat, provide demonstrations, troubleshoot issues (StressCheck Clinic), and answer questions about our training course, our technical presentation, our software products and our composite repair solutions.

The StressCheck Clinic

StressCheck users may drop by our booth on a first-come, first-served basis to discuss any StressCheck-related questions, issues or feature requests with us. This includes troubleshooting customer models, demonstrating StressCheck features, and providing best practices/tips on how best to optimize StressCheck’s use.

Want to ensure ESRD’s booth staff is well-equipped to answer your StressCheck Clinic request? Click the below button, include “StressCheck Clinic Request” in the message subject, provide a brief explanation, and we will be prepared to discuss your request at our booth. Note: Customer membership level is required.

As a courtesy to other conference participants, we request that StressCheck Clinic visits be capped at 30 minutes.

Participating ESRD Staff

Contact information for ESRD staff participating in ASIP Conference 2022 is as follows:

• Mr. Brent Lancaster – brent.lancaster@esrd.com
• Mr. Brian Lockwood – brian.lockwood@esrd.com

In this “S.A.F.E.R. Simulation” post we will share the key takeaways for engineers and their managers from a recent ESRD webinar on “Durability and Damage Tolerance Analysis Best Practices in the A&D Industry”. We’ll identify the factors that restrain the wider adoption of computational numerical simulation methodologies, and in particular finite element analysis (FEA) software, when used for detail stress analysis in support of critical engineering tasks such as fatigue life prediction. We hope to lift the fog that exists over the limitations of legacy FEA methods that are encountered by even the most expert simulation analysts. These same challenges make durability & damage tolerance (DaDT) calculations impractical if not risky for the occasional and especially new engineering user to perform.

Why DaDT is becoming ever more important with aging aircraft fleets….

The C130 Hercules transport aircraft depends heavily on reliable DaDT predictions to stay in service

There are numerous fixed wing and rotorcraft platforms that have far exceeded their initial program estimates for years in service. Keeping these aircraft flying safely with ever increasing performance requirements has fueled the need for more reliable and robust computational tools in fatigue life and fracture crack growth calculations to support the DaDT engineering function within repair, maintenance, and sustainment organizations. Aerospace and Defense (A&D) conferences like the Aircraft Airworthiness and Sustainment (AA&S) and Aircraft Structural Integrity Program (ASIP) have become increasingly important in their role to share best practices and new technologies which can improve aircraft life and reduce cost by expanding maintenance intervals. These conferences have revealed the need for new simulation technologies, and software tools based upon them, which improve the fidelity, accuracy, thoroughness, and speed of engineering analysis with improved confidence, reliability, and robustness of results and processes that is independent of the user or model.

To illustrate this growing demand, a strength engineer performing a “typical” stress analysis at the design stage is often delighted with answers within, say, 5% of actual or expected values. But when performing DaDT engineering simulations, being “close” with stress intensity factor (SIF), beta or other fracture mechanics computations is not good enough. For example, as the below figure demonstrates, being off by as little as 5% in SIF predictions can result in a 350% difference in crack growth cycles. The impact of getting this type of prediction wrong can be catastrophic for engineers practicing in the A&D industry (and beyond).

The sensitivity in DaDT life predictions is driven by unknown risks in the input data (e.g. SIF’s)

The application and value of FEA-based tools for numerical simulation is well established in the commercial and military aviation industry. The structural design, loads, strength and stress groups routinely use finite element models to generate internal loads of entire aero structures. FEA tools are then used to perform detail stress analysis to calculate margins of safety on components that are resistant to engineering handbooks, design curves, closed form solutions, and empirical data.

However, in many organizations there is still a preference for quick hand-whipped stress analysis with ample margins of safety when the alternative is constructing complete 3D virtual prototypes with no detail lacking, or to perform more testing on physical prototypes.

Fast high-Fidelity FEA of large aircraft assemblies is still problematic…

Modeling of large multi-scale spanning geometries for capturing SIF’s is unfeasible in most FEA codes

The wider-spread use of FEA tools in fatigue and fracture domains for DaDT calculations is another matter. Over ESRD’s twenty plus years of working within the aerospace community, as well as attending industry conferences like ASIP and AA&S, we have observed a reluctance to turn to the FEA tool kit in the calculation of important DaDT engineering data such as SIF’s. This is surprising as ever-increasing demands on airframe performance and life expectancy are requiring a larger volume of higher-fidelity structural analyses be conducted with improved levels of certainty and confidence. This is occurring at a time where budgetary constraints translates into fewer engineers available to perform analysis work that has become more complex, all with less time for advanced training and fewer resources to rely upon in methods and tools support groups.

In interviewing engineers and their managers who are responsible for DaDT work, we have heard these reservations about the generic use of FEA:

“It takes too long to import and clean up the geometry then build a high-resolution mesh around a high-risk or damaged component.”

“Solving crack propagation problems on my desktop computer takes too long as it is, then I have to go thru many cycles to debug and tune a model to get a result that is believable.”

“The quality of my solutions are a subjective exercise at best, based on my years of experience in handling similar types of analysis problems.”

“My team managers have more faith in historical analysis methods and it’s hard to convince them to let us loose on a digital model.”

All of the above issues were indeed valid at one time. It is not surprising that an organizational dependency arose on using closed-form solutions and empirically-based handbook tables to predict SIF’s. That was true even for design geometries and load cases that had little resemblance to their textbook surrogates.  Yet, not every analysis can be reduced to well-known cases like a simple plate with a thru-crack. It can be risky to force fit an existing curve or table to meet the needs of an analysis which is clearly well out of its original scope. An example is the use of compounding beta factors to account for variances in geometry and loads which can be precarious to apply and prone to error.

Despite these challenges, many DaDT engineers, rather than changing the legacy processes of their organizations, rely on historical methods no matter however approximate they are.  When these simpler methods failed, they would as a last resort – clearly not the first choice – turn to FEA for modelling complex 3D geometries with a wide variety of loadings, material types, residual stresses, crack shapes, and other complicating features.

Another inconvenient truth…

Despite their longevity in the industry, even legacy FEA methods and software struggle with these more complex classes of problems in DaDT, even when employed by simulation experts.  Obtaining consistently accurate and numerically verifiable solutions with traditional finite element methods has unfortunately added more complexity, time, risk, and cost that was prohibitive for many organizations to endure, especially when they were seeking speed, confidence, and safety.  Only a few highly experienced and well-trained DaDT specialists could perform the work due largely to endless sources of approximations, idealizations, decisions, judgement calls and errors in modelling, analysis, and results interpretation. There was little time available to think about numerical verification, much less understand it was not the same as results validation.

The reason for this state of simulation in DaDT is often obscured by a fog of complexity hiding underneath the hood of legacy FEA codes. The foundational finite element theory, methods, and technology base implemented by nearly all commercial FEA software products has remained largely unchanged over decades. That is not to say there have not been substantial improvements in aspects of FEA such as model creation for faster preprocessing, high performance computing for faster analysis, and improved visualization for post-processing. Yet, these only masked underlying limitations that made FEM an art for the expert masters rather than a reliable numerical computational science for the engineering masses.

These limitations are well known to users of simulation software – as evidenced by the size of the element library – but are less so recognized by their managers who often think this is just the way it has to be. In our next S.A.F.E.R. Simulation post we plan to discuss how these limitations in legacy FEA throttle the wider use and economic value of numerical simulation across the A&D industry. Nowhere is this timelier than in the supply and service chains which have increasing authority for design and analysis, and now new accountability for lifecycle maintenance and program sustainment that requires deeper expertise in DaDT.

Fixing the Holes…

Example 3D crack life calculation using FEA-based methods (ESRD’s Crack Propagation Analysis Tool)

For the last decade ESRD has been at the forefront of advancements in numerical simulation that makes the performance of finite element analysis less a craft of modelling traps, tips, and tricks when practiced by experts, and more S.A.F.E.R. methodology when used by the non-expert. With these advancements it is now possible for DaDT engineers to conduct analyses using more transparent models with greater accuracy, producing faster simulations in more efficient workflow processes which require less re-meshing and debugging, and generating more reliable results from inherently more robust methods independent of the level of expertise of the user or complexity of the engineering problem.

In a future S.A.F.E.R. post on the use of FEA in DaDT we will dive deeper into what makes this now possible in practice. Until then, in the most recent ESRD webinar on DaDT we demonstrated several example fatigue life and crack propagation problems which illustrated that conventional expectations of being “close enough” are no longer “good enough”.  To view this webinar click here. If your corporate firewall prohibits live access please send us an email to webinars@esrd.com and we can provide a link to download.

What do you think…

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Related links and conversations…

• ESRD’s DaDT and Fracture Mechanics Application Highlights (via ESRD.com)
  • Learn about the types of DaDT and fracture mechanics applications for which ESRD is best suited, and how A&D engineers solving legacy aircraft problems can benefit from our simulation technology.
• Seven Questions to Ask CAE Vendors of Structural Analysis and Simulation Software (via Engineering.com)
  • Engineering.com Editor Shawn Wasserman highlights what questions are driving simulation technology and development, and what factors should determine the best tool for a simulation (such as DaDT).
• NAFEMS World Congress 2017 Tackles the Big Issues in Simulation and Analysis (via Digital Engineering)
  • DE’s Jamie Gooch describes the events and presentations given at the most recent NAFEMS World Congress, including how ESRD’s Chairman Dr. Barna Szabó warned against democratization of simulation without Simulation Governance.

To receive future S.A.F.E.R. Simulation posts…

ESRD, Inc. will be exhibiting and providing a training course at the ASIP Conference 2019 in San Antonio, TX from December 2-5, 2019.  We hope you will drop by our training course and booth to check out the latest!

ESRD’s Training Course

The training course titled “Automated 3-D Crack Beta Curve Development via Smart Sim Apps” will be held Monday, December 2, 2019 / 6:00 PM – 8:00 PM by Mr. Brent Lancaster.  The description is as follows:

In the past, fatigue crack growth in 3D was typically analyzed with a compounding (or superposition) of beta factors to represent various configurations and loadings for complex components. While compounding approaches can be simulated quickly, many of the beta factors used for DaDT simulations were derived from analytical or empirical models of much simpler configurations, which may not be representative of the 3D case at hand. Thus, a risk of the “unknown” is introduced into the simulation, endangering the ability of DaDT analysts to provide a justifiable assessment of 3D fatigue crack life. To mitigate this risk, recently the numerical simulation community initiated the development of engineering simulation applications, or Sim Apps, to automate parametric finite element analyses (FEA) of complex crack components such that the practice of compounding beta factors could be replaced with fully representative beta factors.

Example Smart Sim App for Automated Computation of Multi-Phase Beta Factors (with Built-In Solution Verification)

This short training course will discuss the creation of Sim Apps for the automatic generation of complex, solution-verified 2D and 3D beta factors via the integration of StressCheck’s parametric FEA engine, the Windows Component Object Model (COM) and Microsoft Excel VBA. This SAFER Simulation approach reduces the error-prone superposition of stress intensity factors (SIF’s) to represent complex beta factors.

Course Outline:

• Overview of fracture mechanics parameters for fatigue crack growth: SIF’s, J-integrals and beta factors.
• Pros and cons of compounding beta factors: what are the risks?
• What is a Sim App, and how can they help DaDT engineers produce more accurate analyses?
• Case studies in Sim Apps for the automation of 2D and 3D beta factor generation
• Live Sim App Demo: automated beta curve generation via an Excel VBA + StressCheck-based Sim App
• Q&A

The training course content will be based on concepts from the following resources, available on ESRD’s Resource Library:

• Automated Beta Curve Development Using Parametric FEA
• StressCheck Demo: Sim App Development via Excel VBA and StressCheck API
• Fracture Mechanics Sim Apps: Sample Visual Basic Application
• Crack Propagation Analysis Tool for 3D Crack Simulation: A Simulation App Case Study
• Deployment of Smart Simulation Apps in Support of DaDT Activities
• 3D Crack Growth Simulation: Advancements & Applications Webinar
• Democratization of Simulation Governance-Compliant Sim Apps Webinar

Register

ESRD’s Exhibit Booth

ESRD’s Brent Lancaster chats with ASIP 2018 attendees.

ESRD can be found at Booth 25 and will have several staff members available to chat and answer questions about our software products and DaDT solutions.

Introducing the StressCheck Clinic

We will also be introducing the StressCheck Clinic at ASIP Conference 2019, where StressCheck users may drop by our exhibit booth (at a communicated time or on a first-come, first-served basis) to discuss any questions, issues or feature requests with a qualified ESRD representative. Stay tuned more more details on this new offering!

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Participating ESRD Staff

Contact information for ESRD staff participating in ASIP Conference 2019 is as follows:

• Mr. Gordon Lehman, PE – gordon.lehman@esrd.com
• Mr. Brent Lancaster – brent.lancaster@esrd.com

ESRD is hosting joint webinars on July 17th and July 29th, both at 1:00 pm EST.

Want to learn from the experts in FEA-based Simulation Application (Sim App) development for standardization & automation of complex engineering analysis tasks, such as 3D fatigue crack growth, 3D ply-by-ply laminated composite analysis or other challenging applications you’d like to safely put into the hands of non-experts?

This July, ESRD will be partnering with several industry leaders to provide not one but TWO stimulating webinars on the latest in FEA-based Sim App development.

The Latest Developments in Sim Apps for 3D Crack Growth Simulations

BAMF Example Crack Front Estimate via StressCheck/AFGROW Integration (courtesy Hill Engineering).

First, ESRD is pleased to join Hill Engineering, LLC (developers of BAMF) and LexTech, Inc. (developers of AFGROW) for a joint webinar on Wednesday July 17, 2019 @ 1:00 pm EST. This collaborative webinar will be titled “3D Crack Growth Simulation: Advancements & Applications“, and will detail the latest technological advancements in Sim Apps for accurate simulation of three-dimensional metallic crack growth via coupled finite element analysis (FEA) and fatigue life computations.

During this webinar, you will see the latest in 3D crack growth predictions via Hill Engineering’s Broad Application for Modeling Failure (BAMF) Sim App, which provides a robust integration between StressCheck’s high-fidelity DaDT/fracture solutions and AFGROW’s crack growth life prediction capabilities.

Additionally, ESRD, LexTech & Hill Engineering representatives will explain how each of their respective technologies seamlessly fit together to enable automated, verified & validated (i.e. backed by experimental data) fatigue crack propagation.

Register Now

The Importance of Simulation Governance in Sim App Development & Deployment

This joint ESRD/Rev-Sim webinar will explore Sim-Gov compliant Sim Apps for democratization of simulation.

Then, on Monday July 29, 2019 @ 1:00 pm EST, ESRD will join the thought leaders at Revolution in Simulation (Rev-Sim) for a joint webinar on why Simulation Governance compliance is essential to the development & deployment of Sim Apps titled “Democratization of Simulation Governance-Compliant Sim Apps“.

In this timely webinar, we will discuss why it is essential that Sim Apps implement Numerical Simulation technologies which enable the practice of Simulation Governance in order for the vision of democratization of simulations to be realized, as well as why it is important for engineering managers to get on the Simulation Governance train sooner rather than later. Strategies will be explored for democratizing engineering simulations via Sim Apps which are: 1) based on the latest Numerical Simulation technologies, 2) available in Commercial Off the Shelf (COTS) form, and most importantly 3) Simulation Governance-compliant.

Register Now

More ESRD Webinars…

Interested in the complete ESRD webinar listing, including on-demand recordings from past ESRD webinars? Visit our webinars page here:

View Webinar Listing

Demo of BAMpF/StressCheck interation as run through an AFGROW plug-in (courtesy Hill Engineering)

Announcing Hill Engineering and ESRD Agreement to Jointly Market BAMpF & StressCheck Professional

March 12, 2020

Hill Engineering and Engineering Software Research and Development, Inc. (ESRD) have executed a joint marketing agreement to collaboratively promote the combined use of our software tools Broad Application for Multi-Point Fatigue (BAMpF) and StressCheck Professional, respectively, for the engineering applications of fatigue and damage tolerance analysis.

ESRD is pleased to join forces with Hill Engineering and LexTech, Inc. (an ESRD technology partner and developers of AFGROW) to enable state-of-the-art fatigue crack growth capabilities for DaDT engineers.

BAMpF is a software tool developed by Hill Engineering for predicting the growth of fatigue cracks in 3D parts. Starting from an assumed initial flaw, BAMpF automatically combines fracture mechanics solutions from StressCheck with fatigue life calculations from AFGROW to assess fatigue crack growth performance.

Read Hill Engineering’s announcement.

BAMpF Resources

The following are helpful resources for learning more about the BAMpF/StressCheck/AFGROW integration for fatigue crack growth:

• BAMpF Home page (via Hill Engineering)
• ESRD/Hill Engineering/LexTech Joint Webinar recording (recorded July 2019)
• AFGROW/BAMpF Training workshop (courtesy LexTech/Hill Engineering/ASIP Conference 2019)
• BAMpF Use Case presentation PDF (courtesy Brian Boeke/AFGROW User’s Conference 2019)

BAMpF Case Study Example

The figure below shows a comparison between the fatigue crack growth predicted near a hole (using BAMpF and StressCheck Professional + AFGROW) and results from a fatigue crack growth test for similar conditions. In this case there is an initial flaw at the edge of the hole and the hole has been cold-expanded to introduce compressive residual stress.

Predicted crack front evolution (blue) compares favorably with the observed experimental result (red):

Want to Learn More? Contact Us:

• Hill Engineering
• ESRD

BAMF running as an AFGROW plug-in (courtesy Mr. Josh Hodges/Hill Engineering, LLC)

On July 17, 2019 a joint webinar on the latest developments in FEA-based 3D crack growth simulation, titled “3D Crack Growth Simulation: Advancements & Applications”, was provided by ESRD’s Brent Lancaster, LexTech’s James Harter and Hill Engineering’s Joshua Hodges.

In this webinar, we detailed the latest technological advancements for accurate simulation of three-dimensional crack growth in metallic structures, with and without residual stresses, via coupled finite element analysis (FEA) and fatigue life computations. Additionally, the webinar expanded further on the DaDT analysis best practices presented in ESRD’s June 2017 webinar, titled “Durability and Damage Tolerance (DaDT) Analysis Best Practices“, and highlighted the importance of mitigating the errors of approximation associated with stress intensity factors (SIF’s) and if applicable, engineered residual stresses (e.g. cold-working).

Webinar attendees from a wide range of industries were treated to a demo of Hill Engineering’s Broad Application for Modeling Failure (BAMF) Sim App, which provides a robust integration between StressCheck’s high-fidelity DaDT/fracture solutions and AFGROW’s crack growth life prediction capabilities. The BAMF demonstration showed how to set up a parametric model for DaDT analysis via StressCheck and then, with limited user intervention, integrate with AFGROW and StressCheck via their respective COM API’s to perform an on-demand 3D crack growth simulation. It was very impressive demo, indeed!

View Webinar Recording

Click the button below to view the 3 part, 65-minute webinar recording (scroll to the bottom of the webinar landing page to find the videos):

View Recording

View Webinar Slides

Click the button below to view the webinar slides (PowerPoint Show):

View Slides

Additional Resources

During the webinar, we identified several relevant DaDT and/or crack growth simulation resources that may be of interest:

• “Analytical Modelling of Fatigue Crack Behaviour Under Representative Spectrum Loading in the F/A-18 A/B Y508 Wing Root Shear Tie”, Dr. Kevin Walker (DST Group)
• “Crack Aspect Ratio Investigation, Analytical Methods Subcommittee: Round Robin for Cx Holes”, Mr. Robert Pilarczyk (Hill Engineering, LLC)
• “Benchmarking Problems in Fatigue Crack Growth Analyses”, Mr. Robert Pilarczyk (Hill Engineering, LLC)
• “Numerical Simulation Series: Fracture Mechanics Parameters”, Dr. Ricardo Actis (ESRD)
• “Improving Global-Local Simulation Workflows for High-Fidelity Stress and Damage Tolerance Analysis”, Mr. Eric Buettmann & Mr. Gordon Lehman (ESRD)
• “Computation of SIFs for Cracks in Cold-Worked Holes”, Dr. Ricardo Actis & Mr. Matt Watkins (ESRD), Dr. Scott Prost-Domasky (AP/ES) and Mr. Joshua Hodges (USAF)
• “Crack Propagation Analysis Tool for 3D Crack Simulation: A Simulation App Case Study”, Mr. Matt Watkins (ESRD)
• The Contour Method for Measuring Residual Stresses (Hill Engineering, LLC)

Acknowledgments

As always, many thanks to our attendees for their interest and feedback! And, of course, thanks to LexTech and Hill Engineering for their time and contributions. We hope to collaborate on another webinar in the future!

BAMF Example Crack Front Prediction via StressCheck/AFGROW Integration (courtesy Hill Engineering).

ESRD is pleased to join Hill Engineering, LLC (developers of BAMF) and LexTech, Inc. (developers of AFGROW) for a joint webinar on July 17, 2019 @ 1:00 pm EST. This collaborative webinar will be titled “3D Crack Growth Simulation: Advancements & Applications“, and will detail the latest technological advancements for accurate simulation of three-dimensional metallic crack growth via coupled finite element analysis (FEA) and fatigue life computations.

During this webinar, you will see the latest in 3D crack growth predictions via Hill Engineering’s Broad Application for Modeling Failure (BAMF) software tool, which provides a robust integration between StressCheck’s high-fidelity DaDT/fracture solutions and AFGROW’s crack growth life prediction capabilities.

Additionally, ESRD, LexTech & Hill Engineering representatives will explain how each of their respective technologies seamlessly fit together to enable automated, verified & validated (i.e. backed by experimental data) fatigue crack propagation. You don’t want to miss it!

Register Now

ESRD’s Brent Lancaster prepares to discuss StressCheck with attendees during a break at ASIP 2019.

This past week at ASIP 2019, ESRD provided a 2-hour training course titled “Automated 3D Crack Beta Curve Development via Smart Sim Apps”, chatted with “patients” at the StressCheck Clinic, and exhibited at our convenient booth (above).

ESRD’s Brent Lancaster and Gordon Lehman enjoyed meeting many of the ASIP attendees, connecting with a wide variety of customers and colleagues, and sharing ESRD’s expertise on the development of FEA-based Sim Apps during our training course. As always, thanks to those who attended the training presentation and/or stopped by our booth to say hello to Brent and Gordon.

We were also pleased to learn that quite a few of this year’s ASIP presentations incorporated StressCheck (or StressCheck-Powered Sim Apps) to enhance their DaDT simulations. We are grateful to be included in the “toolboxes” of these ASIP engineers, and look forward to supporting their future fracture mechanics modeling challenges.

ASIP 2019 Training Materials Available…

ESRD Training Course Poster at ASIP 2019.

On Monday, December 2nd, Brent had the pleasure of providing a training course on the development of FEA-based Sim Apps for the automation of 2D and 3D beta factors to a group of ASIP engineers. Thanks to those who attended and/or requested the training course presentation.

ESRD’s Brent Lancaster provides a training course at ASIP 2019.

If you are interested in this topic, you can download Mr. Lancaster’s training presentation (in PowerPoint show or PDF format) from the link below:

ASIP 2019 Training – Automated 3D Crack Beta Curve Development via Smart Sim Apps

We are looking forward to receiving your feedback on the training course presentation.

Note: if you are not a current ESRD customer and would like to evaluate the Sim App examples, please contact us for a trial evaluation of StressCheck. In the “Comment or Message” box, please write “I would like to explore the ASIP 2019 Sim Apps.”

Upcoming Webinar…

Keys to mastering StressCheck Professional are explored.

We are pleased to announce a Q1 2020 webinar titled “Mastering StressCheck: Practical Training Approaches & Online Resources for A&D Engineers“. The abstract is as follows:

Strategies for mastering StressCheck Professional for a variety of Aerospace & Defense engineering applications, and a review of the available training options and online resources, will be explored.

Learn more and register for the February 12th, 2020 webinar: