Learning Forum

[Rameez_ul_Haq]

,I am going to address an important aspect of FEA and I would like to know your thoughts on this one.nIf you observe the pictures I shared in my previous comments regarding the singularity, can you tell a way to overcome these singularities? For the sharp corner, we already know a fillet will work. But now consider the singularities in the first picture. There exists a singularity right next to the fixed support (for solid elements). In reality, the stiffness is not going to be infinite there. But there would definitely be an elevated stiffness there (as compare to the rest of the model) and there would also exist a reaction force there. Now, if I try to make a convergence study for this in FEA, I would see that the stress is rising and diverging just at the transition from the fixed support to the regular stiffness of the structure. Maybe 2 or 3 elements away, the stress is going to be okay to depend upon. But can we conclude that even though the transition is showing a singularity, but in reality the stress at that location is going to be somewhat close to the stresses which we are seeing 2 or 3 elements away from there? I mean is this a sensible conclusion? Or the stress at that transition is not going to be close to the stresses 2 or 3 elements away from there? nThe same goes for the singularity at the location where there is a transition between the force area and the area right next to it where there is no force (in the first picture). That is a singularity, meaning the stress would be diverging. But is there a way to know the actual stress at that transition by overcoming the singularity? What should we expect at that location in the reality?nAnd also (as shown in the second picture) can you tell what happens to the stresses when there is a abrupt transition from one material to the other in reality? In FEA, it might show up as a singularity, but what about in reality? How can we overcome this singularity so that we can draw some reasonable stress results.n