I have been pretty happy with Algor after about a year. It has a good user interface and imports/meshes Solidworks pretty well.
Looked at Cosmos also, beware that for more advanced analysis (can't remember details but I think nonlinear materials and dynamic response) you have to go into a...
Agree with Brad, clamping is often the weak link, but I think someone above modeled with little effect. Also doesn't explain the simply supported results. However there are some potential issues in the simply supported results depeding how its done.
At this point these seem the likely...
A lot of good discussion here, a few points to consider.
The force measurement could easily be in error depending what you are using to measure it. A typical load cell might have 0.1% accuracy, so a 5000 lb capacity load cell is only accurate to +/- 5lb. What are the specs on the Instron?
You...
>The original shuttle design did not reflect any proper and competent calculation of mechanical transients.
> The failure to properly calculate the transient loads is a 70 to 100% error
Some pretty serious generalizations/accusations here. Any evidence?