射出成形短繊維強化複合材料の曲げクリープ変形の成形異方性とその予測

抄録

Flexural creep deformation behavior of an injection-molded short fiber composite material has been investigated with an emphasis on its anisotropy, stress dependence and temperature dependence. Three-point bending creep tests are conducted on test specimens with different orientations oblique from injection direction at room and high temperatures, respectively. It is shown that the creep deformation at room temperature develops more markedly with the increase in off-axis angle from 0° to 90°. The creep deformation increases as creep stress increases, regardless of the off-axis angle of specimen. It is also observed that creep deformation turns to be more significant at high temperature compared with that at room temperature. A phenomenological constitutive model has been developed to describe the orientation dependence, stress dependence and temperature dependences of the observed creep deformation behavior. It is demonstrated that the flexural creep deformation behaviors of short fiber composites at different temperatures can adequately be described using the proposed creep model. The creep model established allows identifying the flexural creep rupture stresses at any temperature in a range by means of a strain-based failure criterion.