一方向炭素繊維強化熱可塑性樹脂の異方性弾塑性挙動の観察と材料構成則（異方性降伏関数とゆがみ硬化則）

• 発表時期：2023年
• 学会/論文誌名：日本機械学会論文集

内容

A series of numerical material tests based on homogenization theory are carried out to characterize the anisotropic elastoplastic and hardening behavior of thermoplastic resin reinforced in one direction by carbon fibers (UD-CFRTP), and a new constitutive model is proposed to describe the characteristic material behavior. First, macroscopic stress-strain curves are obtained from numerical material tests (NMTs) conducted on a unit cell model, i.e., a representative volume element of periodic microstructures, to which uniaxial and combined stress states are applied under various conditions of stress ratios and stress paths. Using the obtained NMTs results, the initial shape of the yield surface and its evolution are investigated in detail. The results suggest that even if a resin has isotopic hardening characteristics, UD-CFRTP exhibits complex anisotropic post-yielding or, equivalently, hardening behavior. Then, a constitutive model that can describe such material behavior is originally formulated, and a step-wise identification strategy is presented to determine the material parameters. Finally, by carrying out verification analyses, we confirmed that the macroscopic stress-strain curves represented by the proposed model can be fitted to those obtained by NMTs with sufficient accuracy for practical use and that the performance of the proposed model is much better than that of a conventional constitutive law.