I am trying to master the process of using a temperature load to simulate a preload in solid body elements. I have attached a simple model that I have built in order learn how to appropriately set up before I try to incorporate this method into my more complex product models. I have followed the instructions in the following link:
https://knowledge.autodesk.com/support/inventor-nastran/learn-explore/caas/sfdcarticles/sfdcarticles...
The model runs just fine with no fatal errors. However, the results do not line up with what I expect based on the instructions provided. Per the instructions, the coefficient of thermal expansion is to be set to the calculated dL. With the inputs from the model, this would be:
dL = (10*31,415)/(3.142*26(10^6))
Note that the force was determined by calculating what force would result in a prestress of 10,000 psi (Subcase 1). I did this so that I could check the results and see how in the inputs and results lined up with each other. However, I am getting normal stresses in the direction of the preload of 70,000+ psi. I know that due to deflections that the stress would not equal exactly 10,000 psi, but I know it should not be that far off. I do not know where I am going wrong. Maybe it is in the material set up. I used orthotropic 3D for the preloaded member in order to have differentiated thermal expansion coefficients. I am not experienced with this as virtually all of my experience is with alloy steels which are isotropic in nature (that’s why I specified the same elasticity and shear moduli in all directions). Any guidance on where I am going wrong is greatly appreciated.
