A staple is a short piece of wire driven through and bent to bind together papers etc. The bending process takes place very slowly such that inertial effects are negligible and it can be termed as quasi-static. Quasi-static problems can be simulated well with either Abaqus/Standard or Abaqus/Explicit. Typically, quasi static problems are solved with Abaqus/Standard but may face convergence difficulties due to contact or other nonlinearities. Such problems are a good candidate to be solved with Abaqus/Explicit as explicit procedure can resolve complicated contact problems and other discontinuous nonlinearities more easily than Abaqus/Standard. The bending of staple is performed here using Abaqus/Standard. Initially, the “hard” contact relationship, which is default in Abaqus, is used. Due to presence of sharp corners, the convergence difficulties arise. To overcome these difficulties at the contact interface, the “softened” pressure-overclosure relationship is used. The “soft” pressure-overclosure relationship, which allows some penetration, can make it easier to resolve the contact difficulties. This relationship makes it easier to simulate the bending of staple and also the convergence is achieved quicker using less increments.
Note: This exercise is part of the Solving Non-linear Problems with Abaqus course.