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Theory behind the evaluation of normal vectors in COMSOL Multiphysics
Posted Oct 19, 2020, 8:56 p.m. EDT Geometry, Structural Mechanics Version 5.4 0 Replies
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Hi COMSOL users,
I am studying the effect of semi-elliptical surface cracks on the fatigue life of pipeline welds using the COMSOL single-edge crack tutorial (in version 5.3a or older) based on the J-integral as a benchmark.
I was wondering if anyone knows the theory behind the definition of the unit normal vectors applied in this tutorial. My model is defined by a crack depth and length, a and c, respectively. In my model (please see attached images) it is relatively straightforward to define the unit normal vectors on the edges bounding the crack depth 'a' as -1 or 1 depending on the direction. However, it gets complicated when I move to the weld region and try to define the unit normal vectors on the edges bounding the crack length 'c'. I have tried to define them by using an estimated angle of 30 degrees but this angle is inconsistent as I increase the size of the crack particularly 'c' along the weld region.
Does anyone know the theory behind the definition of these normal vectors as used in COMSOL or have a sophisticated way of defining them. I would really appreciate any suggestions.
Kind regards, Ayo
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Hello Ayodeji Olamide
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