How does COSMOS define compressive strength

Hi James, a quick review of basic FEA might help here. COSMOSWorks doesn't define or even require "strength" information in a linear analysis and only requires Yield Strength in a nonlinear plasticity analysis. A Static analysis only requires Young's Modulus and Poisson's Ratio to complete the stress/deflection calculations. The failure strengths, Tensile & Compressive, are listed in the database only as a reference to you. The solver doesn't look at them.

So... in answer to your question, COSMOSWorks doesn't define Compressive Strength because it doesn't really care what it is to do its job. That said, 304 is an extremely ductile SS at room temps and ductile materials tend to have the same compressive properties as tensile properties (a characteristic called 'symmetry') While the data gnome who typed all these properties in many many years ago may simply have neglected to enter a compressive strength, it is equally likely that he assumed compressive strength was equal and opposite to tensile and left it blank intentionally. I opened 2 references I keep on my desk and neither list a compressive strength for 304.

Make sense?

Vince

In any static linear analysis performed in a FEA program the program calculates deformation results first based on the applied loads and boundary conditions. Once knowing the deformed and undeformed shapes, strain is calculated and once knowing the strain results, stress results are calculated. In calculating the stress values based on the strain results only Young's Modulus (E) and Poisson's ratio are used. Yield stress values are only used in factor of safety's calculations when performing linear analysis problems.