Impact and energy absorption of long fiber-reinforced thermoplastic based on two-phase modeling and experiments

Impact behavior and energy absorption of long fiber-reinforced thermoplastic (LFT) plates under low velocity impact load is investigated based on two-phase modeling and experiments. In this study, strain rate dependent properties and fiber distribution are characterized by mechanical tests and X-ray CT scans. A two-phase homogenized material model is established and validated by impact test data. On this basis, this paper presents a method for the assessment of the energy absorption capability of LFT plates, which defined as a power law equation normalized by penetration energy. The accuracy and applicability of the proposed approach is validated by finite element simulations of three impactor diameters. The results show a good consistency and indicate that the exponent of the power law is probably independent of the fiber content distributions and impact conditions. The expression of minimum penetration energy is derived and can help in a quick design of fiber volume fraction and plate thickness.