The tension is too high

Hi guys! I have a question: I'm doing a static analysis of this object. As you can see in the photo, the results of this analysis show tensions that are higher that the yield strenght. In order to reduce that I tried to thick the mesh around the holes and I also tried to reduce the loads without, however, a tension drop. As you can see from the photo there are some screws that I modeled with BEAM  and RBE2 elements. Do someone know the reason why the analysis give this results? 

Thanks in advance 

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