Computational Solid Mechanics Laboratory 本文へジャンプ
Research on polymers (polymeric materials)

   In this laboratory, some research regarding polymers, or plastics, as well as metals is carried out. Almost all daily necessaries around us are polymer molding. In addition, polymers are used as strengthening members (e.g., bumpers of cars) because of their light weight and high strength. Strengthening members are generally used under the condition of a large load or a large impact. Designing structures safely with such materials requires a sufficient grasp of their material properties and resulting deformation simulations with high accuracy.

                                           Fig. 1 Bumper of a car

  We have been conducting research from various angles, aiming at predicting the deformation behavior of polymers with high accuracy by simulation. It is known that the polymer blend technique improves the material properties of polymers. Polymer blends are made by taking some different materials and mixing them with a polymer, which is used as a base material. For example, a polymer blend with rubber particles inside it has higher toughness than normal polymers. However, as the polymer blend becomes deformed, the particles debond or break to form voids. Considering the circumstances mentioned above, we have been pursuing the construction of material models from both angles-experiment and simulation-considering the following:
(i) anisotropy that spherical voids grow into elliptical figures along the tensile direction
(ii) the effect of volume change with void growth.

  Fig. 2 Variation in the spherical shape of voids with material deformation

   Additionally, there are many other factors to be considered such as anisotropy due to molecular chain orientation along the tensile direction, temperature dependence, strain rate dependence, etc. We conduct some experimental research focusing on these factors using normal polymers.

          Fig. 3 Comparison between experiment and simulation of the deformation behavior
                           (tensile test using a polymer blend)