Interface for LS-DYNA supports large-deformation simulation
Recently, it is in high demand to estimate and evaluate the behavior during large deformation of micro-structured composites which contain phase separation and filler, by performing simulations.
Existing FEM engine of J-OCTA, “MUFFIN-Elastica” is for elastic simulation and is specialized for the behavior during a small deformation.
To extend its applicability to FEM simulation, the updated J-OCTA 4.1 version will provide the interface for a multi-purpose nonlinear structural analysis engine “LS-DYNA”.
The phase-separated structure computed by “COGNAC or “SUSHI” can be output as a mesh data for LS-DYNA simulation. After the user specifies the material properties for each component and deformation (boundary) condition, LS-DYNA simulation can be started from J-OCTA directly. As a material model being appropriate for nonlinear structural simulation, materials including elastoplastic, viscoelastic, and hyperelastic such as rubber are available for use.
From version 4.1, J-OCTA can deal a large-deformation FEM calculation of a multi-phase structure which contains phase separation and filler dispersed structure.
Example Case Study: Nonlinear Mechanical Properties of Composites
The phase-separated structure of a resin material (e.g., polypropylene) which is popular in the automobile industry varies depending on the type and the content ratio of the additive substance. It results in the different material properties. In this case study, you can find an example of the J-OCTA and LS-DYNA coupling analysis of mesoscale simulation that considers the phase-separated structure of a polymer.
A function to create an RVE highly-filled with fillers.
Sometimes you wish to perform FEM simulation with micro-structured representative volume elements (RVE) for a composite material which is highly-filled with fillers.
When creating such highly-filled structure, e.g., filled over 50 vol%, it may not be easy to arrange fillers. COGNAC, the molecular dynamics engine of J-OCTA, can easily arrange fillers which are in the shape of a sphere, rod, or disk to highly-fill a rectangular domain.
For nonlinear FEM simulation, J-OCTA can transfer the resulting structure to Digimat-FE directly, or, convert the structure into STL format or a concentration data to the general purpose structural analysis software.
Example case study: Thermal analysis which considers the dispersibility of graphene sheets
By adding graphene sheets, the thermal conductivity of a CFPRP material can be improved. However, when unmodified graphene sheets are added, they aggregate and then the thermal conductivity may not be improved as much as expected.
In this case study, how much the surface modification of graphene sheets changes the dispersibility is simulated by using J-OCTA. The thermal conductivity is then computed by using Digimat-FE/Solver.