HI all,
I am trying to manually put in two sets of threaded nuts and bolts into a larger assembly in order to determine if the forces will create stresses on the bolts that will potentially cause them to be stripped/fail. I am aware of bolt connectors, but I would like to use the bolts I have for this simulation. I also was having trouble with the bolt connections because I do not have a circular edge where the bolt head would be placed.
I am having trouble mating the threaded nut to the bolt so that there is no interference and that the nut is also touching the bottom face of a plate in the assembly.
I am applying two main forces to the largest part of the assembly that the bolts are trying to keep stationary and a clamping force/axial load on the bolts. My fixtures are on the sides of the bottom plate and in one simulation, I tried to fix the bottom of the screws because they were the only parts moving freely.
The assembly is symmetric, so I tried to start a 2D static simulation but I cannot figure out how to model/mate the threaded nuts and bolts on the assembly.
If anyone has any advice on how to proceed, it would be greatly appreciated. I have attached some photos of the assembly model for reference.
I think most people would advise against ever trying to model threads explicitly. A cylindrical surface at the root diameter of the softer material, or the smallest diameter, will give useful forces and relative stresses for handbook calculations.
If you insist, and have the resources to run an ultra fine mesh in full contact analysis, model the threaded parts together in context. The exact same sketch-sweep should cut both sides of the thread. Then you can be sure the helixes are clocked together with uniform clearance.
>The assembly is symmetric,
A helical thread is not symmetric in any plane or axis.
>I do not have a circular edge where the bolt head would be placed
It is common to edit base geometry to force a circular edge, e.g. making a slotted hole a cylinder in a simulation configuration. The 'bolt connector' is the only way I've found to model a fastener with accurate preload and bolt stretch.