Strength validation of structures:
What is it and how does it work?
Strength validation; what is it?
Strength analysis of a designed structure comprises the evaluation according to international standards. It is the check whether all requirements are satisfied as specified by standards provided by DNV, Eurocode, API, AISC etc. .
Nowadays, calculations of most constructions are performed by Finite Element Method (FEM) software packages.
A straight forward FE model (without modelled built-in tolerances) usually represents an ideal world with flat surfaces, straight stiffeners etc.
In this case, for instance, a buckling strength analysis will present too optimistic results. In reality offsets, due to built-in tolerances, will have a major influence on the buckling strength results. Without modelling these in detail, your calculated results with FEM are not very practical. On the other hand, modelling these discrepancies is very time consuming.
After building your FE model and running it to analyse the strength and stiffness, it is also important to know whether the structure fulfills the requirements as laid down by certifying requirements like DNV and ABS and general guidelines like ISO, API, Eurocode etc. These standards take care of things like:
- Product (built-in) tolerances;
- Influences on material properties;
- Environmental influences on the construction;
- Type of profiles used in the construction;
Just remember that a finite element solution is an approximation. The accuracy of answers is determined by various factors. Some can be influenced with the FEA program, e.g: mesh density, but others need to be analyzed in the post processing phase.
Strength validation; how does it work?
FEM Data Streamliner offers you two ways to evaluate your structural design:
- By a hand calculation tool;
- By Finite Element Model check tool (add-on).
Hand calculation tool
With the hand calculation tool, the designer can easily and quickly check what dimensions are required to withstand applied loads / stresses. This way a quick method is offered to dimension the design prior to an extensive Finite Element Analysis.
Finite Element Model analysis tool
After building your FE model and running it to calculate results, the add-on tool helps you to evaluate the calculated forces and/or stresses to verify if they are within the allowables as laid down in the applicable standard. Results are presented in clear plots showing the complete structure.
The software is initially written for FEMAP users who work with NASTRAN NX or ANSYS solver.
But the software can also be used by ANSYS Workbench users to read the results directly into ANSYS.
The following links contain an explanation on how the add-on works.