We are continuing this series of contact tutorials with a look at 2 important aspects of simulation contact, geometric smoothing and contact stabilization. Both of these techniques are very useful in overcoming problems which tend to delay projects and compromise results quality.
Geometric Smoothing – One of the potential problems with doing contact simulation is that the surface of an FEA model has been approxiamted to either a set of straight lines or first order curves. This approximation of the surface greometry can often compromise the quality of the contact stresses. Abaqus has a geometric smoothing algorithm which recognises where surfaces can be approximated using planar or cylindrical surfaces, and smoothes the peaky surface stresses appropriately.
Contact Stabilization – In the real world many mechanical assemblies rely on the interactions between the various parts to prevent unconstrained rigid body motion. However an FEA solver has to establish how this contact develops without this stabilising influence (it hasn’t calculated what it is yet.) So contact models have a habit of exploding, or heading off to infinity, before any useful results are ever calculated. Stabilising the model in this critical initial phase of the solution is often the difference between success and failure in an analysis, and there are many options and techniques in Abaqus which help bridge this gap without compromising the quality of the results obtained.
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