Tech Briefs

Mesh Gluing in Thermo-Mechanical Solutions

We presented in previous ADINA News, mesh gluing applications for mechanical problems without thermal effects (see News of Nov. 30, 2007, Nov. 15, 2007, Apr. 30, 2007, and Jan 15, 2007).

In many practical applications it is desirable to use the same finite element model for mechanical and thermal or thermo-mechanical-coupled solutions. The model might have in different regions fine meshes and coarse meshes of totally different element types connected to each other, e.g., 10-node tets to 27-node bricks. Therefore, we have extended the mesh gluing capability to include temperature degrees of freedom. This option, available in ADINA 8.5.2, can be used with 2-D and 3-D solids for:

  • linear and nonlinear static and implicit dynamic analyses

  • linear and nonlinear, steady state and transient heat flow solutions

  • one-way and fully coupled thermo-mechanical problems (with or without contact conditions)

To illustrate how gluing for thermo-mechanical problems works, we consider a simple 2-D patch test, with different meshes of 9-node 2-D plane stress elements, confined on three sides and with prescribed convection at the top and prescribed zero temperature at the bottom:

In the plots below, we see a linear temperature distribution and a constant heat flux with no jumps (the exact analytical solution) across the gluing line. Note that the values plotted below have not been smoothed. The effective stress is also continuous across the gluing line:

Below, we show a turbine blade subjected to heat flux, temperature and centrifugal loading. Mesh gluing is used to connect the different meshes used for the root and blade. As shown in the figures below, the temperature distribution across the glued surfaces is very smooth.

Clearly, with thermal effects now also included, the ADINA gluing capability will prove even more useful in many applications.