Aaron Hayden

Interpreting study results

Discussion created by Aaron Hayden on Nov 7, 2007
Latest reply on Nov 17, 2007 by Vince Adams
Hi all,

I know this topic has come up more than once in the past. When one gets results from a study how does one weigh theoretical results against actual field conditions (without actually being able to test the part)? I understand that the study is only as accurate as the data being fed into it. I usually try to keep the model as intact as possible to achieve the most accurate testing scenario, however performance is typically inversely proportional. One thing we don't do is insert weld beads into the models. We run our studys with global bonding for weldments as well as bolted joints as it is the fastest study. Any guesses as to how much error is introduced when using bonded for a bolted joint rather than simulating the fasteners (I'm sure it's a case by case deal)? Then there is the hot-spot issue. Anyone have any first hand experience running a study on weldments with and without the weld beads? The hardest part about running FEA for me is determining how critical the individual hot-spots are (second hardest is by far meshing). Will the material yield in those high stress areas which will then allow the stress to redistribute? Will a crack develop and propagate? Does the hot-spot actually exist? These are seemingly difficult questions to answer.

I've attached some JPEGS of a typical model showing hot-spots. The plot is Design Check (FOS) to Yield. The scale is 0-3. Anyone care to comment on this model regarding hot-spots? I'm certainly not expecting someone to "ok" the design, just your thoughs based on your experiences.

Thanks in advance!