Computational Cost

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  • Last Post 11 January 2019
JL1234 posted this 11 January 2019

Structural problems are generally much more computationally costly compared to heat flow problems. Why is that? 

peteroznewman posted this 11 January 2019

Solid elements for structural models have 3 degrees of freedom on each node (x,y,z displacement), while thermal models have only 1 degree of freedom on each node (temperature). There is a factor of 3 right there.

Small features in the geometry create stress concentrations that must be resolved with many small elements because we are interested in the maximum stress. Small features in the geometry can be meshed more coarsely in a thermal model because it doesn't create a maximum temperature that is of interest. There could be 3 times as many nodes in a structural model compared with a thermal model to get results that converge on the true solution.

Multiply 3 by 3 and the structural model is now 9 times more costly to compute the solution than the thermal model.

I expect other members may give other examples.

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