Items to check when Evaluating
an FEA Consultant.Basic Consultant Requirements.In order to find the answers to your design problems, there are certain critical things a consultant must be able to accomplish:
- Listen to you and understand your needs.
- Bring to bear their engineering background and experience to understand how to effectively tailor your
FEA to your situation to insure the most accurate and economical result.
- Be willing to work with your engineers and designers thereby improving analysis quality by incorporating your company's expertise into the analysis process.
Provide a Customized Solution which Fits your Individual Needs. FEA is a complex
process which requires more than simply importing geometry from your CAD program. Throughout the analysis process, the analyst engineer must ensure the analysis is tailored to the individual problem's unique demands. There are several concerns the analyst must address in order to arrive at a valid solution to meet your design analysis objectives. The appropriate software tool to use.
There are several different analysis solution codes and methods. Which one is the most appropriate for each specific design situation must be addressed at the start of the analysis process. Model Building.
This is the core of the analysis. The model must be constructed in a way which represents the real world as much as theoretically possible within the software
limits. There is no simple "cookie cutter" approach. Each model must be created specifically to represent the unique challenges of the design analysis. A model of this type can only be created by an experienced modeler. Someone who knows the limitations and strengths of the modeling process. Which areas may or may not be simplified.
Each analysis is very complex. In an effort to reduce the analysis' cost and complexity, assumptions are made. The analyst must be able to determine, based on experience and engineering judgment, which portions of the problem may be simplified and which must be modeled in great detail. Loads and Constraints
Another important portion of the analysis is loads and restraints application. Typically, this is the most technically challenging part of the analysis. A great deal of effort and experience is required to understand the how the part
being analyzed is loaded and restrained. Sometimes a subtle difference in restraints and loading can have a dramatic effect on the analysis results. These subtleties are best understood by a person who has the experience and has seen several different analysis problems.
Insuring Accuracy Through Engineering Expertise.Even if the analyst has had years and years of experience, errors will happen. There is a vast amount of data management involved in every single analysis. Whether the analyst is technically good or bad, there are a few items which should be performed in order to help catch any possible errors in the design process. Have
a knowledge of what the end results of the analysis should be. Only by experiencing dozens and dozens of various problems and solutions, is an analyst able to
develop a knowledge base of what different analyses' results should be similar to; how to have some expectation of the results before the model has even been built. If the results are not what was expected, a flag goes up. The analyst then examines the results to see if an error was made, or, if the answer is correct but out of the range of his experience, his knowledge base increases. Use hand calculations to "ball park" the results.
A vital verification method is the use of hand calculations. Although hand calculations are by nature not as detailed as FEA and actual physical testing, they provide a good and relatively quick check on the results' accuracy to ensure the results are "in the ball park". Use Physical Test Results to Verify the Analysis.
The final phase of the
analysis process is the physical test. Every analysis should have, time permitting, a physical test performed. The experienced analyst should be able to know how to correlate the physical test results to the FEA results.
Results Analysis and Interpretation.Anyone who has
been exposed to finite element analysis has seen the multi-colored pictures showing the results. These pictures are nothing more than "eye candy" without the correct interpretation. If the wrong interpretation is provided, or the underlying assumptions which went into the analysis are not understood or properly described, the pictures are worse than useless. They can be dangerous! The professional analyst must be able to: Relate design performance under subjected loads and restraints being considered. Interpret the results in a meaningful and accurate way. Communicate to the customer how the assumptions made effect the results.
Make recommendations for design changes based on design performance.
Customer Relations.Even if the analyst is extremely
technically competent, if he is unable to relate to the cutover orally and at the end of the project with a written report, the analysis' usefulness deteriorates rapidly. The analyst must be able to communicate effectively during the project and upon project completion. Typically the following must be reproduced in the final written or oral report: Project Goals and Objectives:
What the analysis was supposed to determine. Complete Modeling and Run Information.
Provide enough information to enable the analysis to be repeated at any point in the future. List all Modeling Assumptions.
Based on these assumptions, what the
limitations of the analysis are and how they effect the results. Pictorial, Graphical, and, if necessary, Tabular Results. Results Interpretations.
A section which condenses the results into a format which explains how they relate to the problem and how they are of value to
you, the customer. List Any Sources Used.
A bibliography of outside sources such as hand calculations, etc. Make Recommendations and Suggestions for Design Modifications.
Based on the results make suggestions for design enhancement along the lines of the
original problem. Sometimes, in the course of the analysis, a design issue which was not initially addressed in the problem statement will become very apparent. These should be listed here.
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