“As the United States Air Force continues to extend the service life of their aircraft the Aircraft Structural Integrity Program (ASIP) has had to refine the methods it uses to analyze and predict fatigue crack growth. Through the use StressCheck, coupled with AFGROW, we in A-10 ASIP have been able to more accurately model, predict and analyze critical aircraft structure for the A-10 and other types of structure for non-A-10 system managers. This also allows us within the A-10 to more accurately assess risk for decision makers, streamline aircraft inductions into scheduled maintenance and reduce cost for total life cycle management.”

-A-10 ASIP Manager

"Through the use of StressCheck the A-10 Aircraft Structural Integrity Program's (ASIP) Analysis Group is able to model more accurately the physics of fatigue crack propagation in critical aircraft structure.  Through this tool we are able to model, analyze and predict failure of aircraft structure and then develop crucial inspection and maintenance planes to ensure the safety and sustainability of our nations warplanes.  Without the analysis capability provided to us through StressCheck we would not be able to provide accurate assessments of the A-10 structure to top USAF leadership."

-SWRI Research Engineer, 2012

"StressCheck is the work horse for NAVAIR Structures' detailed stress and stress concentration calculations. This software also is the basis for our development of a Structural Analysis Management System."

"NAVAIR Applications of StressCheck:

• Failure analysis of single and double lap joints in composite laminates.
• Bearing failure analysis of pins in composite laminates.
• Stress analysis of inner wing bonded step lap joints.
• Plastic zone analysis for high and low stress concentration fatigue specimens.
• Calculation of stress intensity factors for multi-connected metal structures.
• Bearing failure analysis for metal/composite hybrid multi-connected structures.
• Buckling analysis of composite panels with delaminations.
• Bearing load analysis of composite laminates with counter sunk holes and adhesive and tape wrapped lugs.
• Tensile and thermal loading analysis of cracked aluminum plates with composite patches.
• Stress analysis of oversized holes in rotor hub lugs.
• Analysis of composite circular doublers.
• Static strength lug modeling tool.”

"Of the three FEA products we use, StressCheck gives me the most confidence when it comes to performing post-processing quality checks on multi-body contact analysis results.  StressCheck has the capability to extract any data of interest and convergence information for that data at any location in the model domain; the other two FEA products do not.  And when it comes to interference fit multi-body contact solutions, I haven't found any software to outperform StressCheck."

In Service Support Center Engineer, MCAS Cherry Point, NC (2011)

"As frequent StressCheck users we rely on the capabilities and reliability of the program to complete our everyday jobs ensuring safe reliable flights of our aircraft. The layout of the program and documentation allow for a quick learning process and the support ESRD offers is second to none. They take the time to answer the most basic questions as well as working through complex problems to ensure the proper validation of results. The effort they make in satisfying their users needs increase the reliability, functionality, and capability of this great program."

USAF Engineer, Hill AFB (2011)

"We have foundStressCheck very useful for computational fracture mechanics for both metallic and composite components. In recent years it has been extensively used in determining beta factors forRAAF's C-130Wing DTA locations and associated generic research."

Dr. Manfred Heller, Head - Structural Mechanics, DSTO (2009)

"In the case of the through crack configuration, the comparison of experimental and StressCheck derived geometry factors showed a close correlation and were an improvement to solutions provided in AFGROW at the time. Based on the results of this research, StressCheck pin-loaded lug geometry factors have since been incorporated into the AFGROW software." Read more...

Dr. Alten Grandt, Purdue University

"Accurate and reliable stresses and Stress Intensity Factors are required for determination of static and residual strength and for crack growth analyses in analysis tools such as AFGROW. For some geometries, industry solutions are either insufficient or nonexistent. The geometry, applied forces, and crack shapes and dimensions must be modeled reasonably well to obtain useful engineering data. The p-version finite element software StressCheck (ESRD, Inc., St. Louis, Missouri, USA) is used to demonstrate how accurate finite element solutions can lead to good quality engineering analysis." Read more...

Analytical Processes/Engineering Solutions, Inc. (AP/ES)

"A screening of existent commercial and non commercial tools was carried out in respect to their fracture mechanics capabilities, their design abilities, implementation as well as their complexity. Although, there are many software possibilities, only those within the reach of the author were evaluated. This resulted in the selection of the commercial tool StressCheck. The assessment of crack propagation on compact tension and two stringer specimens governed by the Paris and Forman regimes was satisfactory compared with experimental results using the material data from simple standard specimens." Read more...

Lloren Llopart Prieto (EADS) - Doctoral Thesis (September 2007)

"Small errors in modeling can lead to substantial errors in joint performance prediction. To alleviate this problem, the CAI used the handbook functionality of ESRD Inc.s (St. Louis, Mo.) trademarked StressCheck P-version finite element software to develop reusable models of typical joints." Read more...

Dr. John Russell - Composites World (May 2007)

"An advanced modeling and analysis tool for complex composite structures is generating benefits across the aerospace industrial base. StressCheck [Composites] is widely viewed as the next-generation composite joint strength tool."

AFRL (February 2007)

"This ability is especially important, not only in support of maintaining aging aircraft but also in analyzing some of the new cold working techniques that have occurred in recent years. Prior to this implementation, analyst often relied on closed-form approximations or simple factors that were often overly conservative and sometimes even unconservative when used in life prediction. Now, not only can we more accurately predict residual stresses in these complex structural joints, we can do so in a timely manner given the modeling and analysis efficiency that exists with a p-version FEA code such as StressCheck."

The Boeing Company (October 2006)

The "StressCheck analysis tool shows significant improvement in bonded and co-cured joint strength prediction capabilities compared to finite element analysis tools currently on the market. Preliminary applications on the F-35 inlet duct assembly joints and independent validation increased program confidence to use this tool on additional structures. As a result of the success with this initial application, the value of the StressCheck analysis tool was recognized for stress analysis of complex composite structural details, and the use of this software on the F-35 program has expanded."

Air Force Research Lab (August 2004)

 The software provides a highly reliable and user-friendly production stress analysis tool that will replace the Finite Element Method (FEM) tools and failure criteria the experts currently employ for analyzing bonded joints. The software includes an FEM-based handbook format, which allows non-experts to utilize models prepared by specialists. The handbook problems include built-in failure criteria, geometric and material nonlinearities, and the modern FEM technology provides better error control and the treatment of very large aspect ratios."

Dr. Stephen P. Engelstad (July 2003)
Technical Fellow
Lockheed Martin Aeronautics Company
Structural Methods and Analysis

which provides efficient and reliable analysis tools for composite bonded aircraft structures. A composites research team from the aeronautics industry, known as the Composites Affordability Initiative (CAI), has just completed an extensive study of current capabilities in the area of failure analysis tools for composite bonded joints. This study led the CAI team to unanimously choose StressCheck as the software tool to replace as well as radically improve existing industry standard software currently used to size bonded joints."

Air Force Research Laboratory (AFRL) Web Page (May 1999)

I have asked one of our AFGROW team members to model the plate and lug cases using StressCheck and compare them to the existing AFGROW closed-form solutions. [He] modeled the cases several different ways to be sure that he was getting the best possible solutions. He has verified that the bearing load option in StressCheck provides excellent results"

Jim Harter
Team Leader-Analytical Fatigue/Fracture Reliability Team
Air Force Research Laboratory (AFRL)