User's want to know; How well does your finite element analysis software predict the response of a physical system to an applied load?  A comparison is made to test data if available, or benchmark solutions (e.g. classical methods, text books).  ESRD provides with the StressCheck software a Handbook Library of parametrically defined models for comparison to published solutions from Timenshenko, Peterson, Mura, Tada, Blevins, Roark, et.al.  If there are differences, are they coming from the mathematical model (in this case an approximation using the finite element method) or are they the result of errors in idealization (boundary conditions, material properties, etc.)?

StressCheck is the only FEA software tool on the market that provides feedback to the user regarding the quality of the computed information.  This 'verification' process assesses the sensitivity of the computed data to changes in the mesh density, order of the element shape functions, and element mapping.  Verification is an important first step in validating the model.

Verification - Am I solving the equations right?
Validation - Am I solving the right equations?
It is clear that validation can only be achieved if verification of the data of interest has been completed.

General guidelines pertaining to the use of mathematical models in solid mechanics were issued by the American Society of Mechanical Engineers (ASME) in 2006 and adopted by the American National Standards Institute. This document describes the importance of verification and validation.

We invite those who are user's of FEA tools to solve the classical Girkmann Problem illustrated in the figure below and send us the results on or before 1 June 2008.  Requested are:
a) Stress resultants Qa (shearing force, kN/m) and Ma (bending moment, Nm/m)
b) The location and magnitude of the maximum bending moment in the shell.
c) Verify the results are accurate to within 5 percent.  Describe how accuracy was verified.
d) Software used, what mesh and type of elements were used.

ESRD recieved responses to this exercise from 15 FEA experts using a range of different modeling techniques and FEA software tools.   Click here to view the results of the study.  These results are also posted in the IACM bulletin.