## Structural & Thermal

#### Why are the linearized stresses different in a 3D solid cylinder model compared to a 2D axisymmetric model?

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The stress linearization equations are described in the Ansys Help: Mechanical APDL Theory Reference Chapter 17: Postprocessing 17.4. POST1 â€“ Stress Linearization or: https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v195/ans_thry/thy_post4.html The main point here is that there is a â€˜thicknessâ€™ assumed (integral of -t/2 to t/2) in the calculations. If the material is at the centerline, this becomes invalid, which explains the â€˜incorrectâ€™ results you get since you are going from 0 (center) to radius. When we perform stress linearization, we are typically considering a thin structure, so we are aware from the centerline (see Figures 17.6 and 17.7 in the page above). We donâ€™t perform stress linearization on a solid tube. Because of this, the solid tube case is not considered or discussed in the documentation. The application of stress linearization to an axisymmetric solid cylinder is not appropriate, so that is why it doesnâ€™t match. If you had a 3D vs 2D axisymmetric hollow cylinder, and you are performing stress linearization through the thin-walled cylinder, the results should match more closely between 3D and 2D axisymmetric.