Matt Morse

Trouble Validating FEA Using Lab Test Results

Discussion created by Matt Morse on Feb 16, 2009
Latest reply on Feb 25, 2009 by Chad Schmidt
Hi Everyone,

I am having trouble making my FEA simulation in Solidworks Simulation match up to lab test data taken on a physical prototype we recently tested. In this case, we're testing for linear geometric behavior of our component, i.e. getting a linear strain response over a given load range. In practice, this component is to be oriented vertically, consisting of 2 horizontal lug holes on either end, 1 to be held fixed on the top end and 1 to hold the load on the bottom end. Between the lugs are some geometric discontinuities as well as the areas of interest for strain measurement. For this test, we take 6 data points in the lab test and I'm currently trying to replicate the strain vs. load relationship in FEA that we saw in the lab. So far I'm not having any luck at all. I've tried making finer meshes, changing aspect ratios, using additional mesh refinements in the areas of interest, and trying a couple different curvature-based meshes with no success. I've also made sure that my restraining bearing load is only holding the upper side of the bearing surface to properly recreate the structural behavior. The load pulling down on the bottom lug hole is also a bearing load which I believe is the most accurate load representation in this case.

I haven't been able to establish any sort of consistent relationship between the lab data and FEA results at all. My FEA results vary all the way from 1/1000th of the lab test data value at the low end of the load range to 30% above the lab test data value at the high end of the range by testing at the same 6 load values tested in the lab. There are some geometric discontinuities in the solid model I'm testing which I believe are causing some havoc, particularly the large slot-like hole between the two lugs but I'm having some difficulty as to how to best approach this. It should be noted that the applied loads to this component are small enough to be well within the linear elastic range of the component's material so Hooke's law is in effect here. As far as software goes, I'm using Solidworks 2009 Premium with Solidworks Simulation Professional. Anyone have any thoughts?