Coupled-field elements PLANE223, SOLID226, and SOLID227 now support plasticity, viscoelasticity, viscoplasticity and creep in structural-thermal analyses. A thermoplastic effect can now be included in structural-thermal and structural-thermoelectric analyses. The amount of plastic work converted to heat is controlled by the Taylor-Quinney coefficient (via the MP,QRATE command). For more information about structural-thermal analyses using these elements, see Structural-Thermal Analysis in the Coupled-Field Analysis Guide.

The ETCONTROL command can now be used with PLANE223, SOLID226, and SOLID227 to control the element technology in structural-thermal and structural-thermoelectric analyses.

You can now use current-technology coupled-field elements PLANE223, SOLID226, and SOLID227 to perform structural-diffusion (KEYOPT(1) = 100001), thermal-diffusion (KEYOPT(1) = 100010), and structural-thermal-diffusion (KEYOPT(1) = 100011) analyses. Example uses for these analyses include modeling temperature-dependent moisture migration and hygrothermal strains in electronic packages or sodium migration in aluminum reduction cells.

To support the new diffusion field, a new concentration degree of freedom (CONC) has been introduced along with the diffusion flow rate “force” (RATE). The diffusivity coefficients are input via new MP command labels DXX, DYY, and DZZ. Saturated concentration is input via the MP,CSAT command. The new concentration gradient (CG) and diffusion flux (DF) result items are now available for diffusion-field postprocessing.

In structural-diffusion and structural-thermal-diffusion analyses, the displacement and concentration degrees of freedom are coupled by the diffusion expansion coefficients input via the new MP command labels BETX, BETY, and BETZ. The reference concentration for the diffusion strain calculation is input via the MP,CREF command. The calculated diffusion strain is available for postprocessing using the output via the EPDI label.

For more information, see PLANE223, SOLID226, and SOLID227 in the Element Reference. Also see Structural-Diffusion Analysis, Thermal-Diffusion Analysis, and Structural-Thermal-Diffusion Analysis in the Coupled-Field Analysis Guide.