Stress-Strain Engineering Approximation & Actual

How often can we get hold of actual material test data❓
The material strength control very much depends on the ingredient mixture or compound mixture at the fabricator.

This is especially true from the steel-related material modelling perspective, although we could utilize the Stress-Strain curve from actual measured tensile test data. However, we will still use the Ramberg-Osgood material model to generate the non-linear behaviour for the CAE analysis, so be it local 3D FEA simulation or global beam analysis.