The Point Impact Responses Of 3D Orthogonal Woven Composite And FEM Calculation

The warp and weft yarns in 3D orthogonal woven fabric provide the highest in-plane stiffness and strength, while the bonder yarn which across the thickness direction can provide the stability of composite material. The excellent integrity of 3D orthogonal woven composite allows the tailoring of properties for specific applications and shows better delamination resistance and damage tolerance, therefore it is used widely in engineering, aerospace, sports equipment, automobile and architecture.As the increasing application of composite in engineering, the study on the mechanic properties under quasi-static and dynamic has attracted more attention in engineering and research. It is proved that the quasi-static indention method and Hopkinson technology are the effective way to analyze the energy absorption of 3D orthogonal woven composite. Because of the difference of the mechanic behavior of composite under quasi-static and dynamic, it is necessary to study the impact responses of 3D orthogonal woven composite material and investigate the difference between dynamic and quasi-static loading. In this work, quasi-static and point impact test will be conducted with Materials Test System (MTS) and modified split Hopkinson bar (SHPB) apparatus. The load vs. displacement curves during quasi-static penetration and impact were obtained to study the energy absorption of the composite plate. Differences of the load-displacement curves between the quasi-static and impact loading are discussed. The results indicate that the load under quasi-static will increase to the maximum at first and then decrease gradually as the interface increasing between penetrater and composite material. The matrix will be deformed and cracked, which causes the more energy absorption with the increasing of displacement. Under the impact load, composite is subjected to a higher value of impulsive loading in a very short time. There is not enough time for the stress wave to propagate to all parts of composite coupon. The damage only occurs in a local area. However, the composite failure area increases gradually as the increasing of impact velocity.This work also applies me to the facet. Based on the microstructure of 3-D orthogonal woven composite, a unit-cell model was established. A compiled user material subroutine which named VUMAT is incorporated with a finite element code ABAQUS/Explicit to simulate the impact damage process of the composite plates. The fluctuation of the impact stress waves has been unveiled. The results indicate that the load vs. displacement curves and energy absorption curves and failure mode of composite plate show good agreement between FEM simulation and experimental results. With increasing of the displacement, the energy absorption and failure of 3D orthogonal woven composite are increased gradually. And it is also proved that the foundation of unit-cell of 3D orthogonal woven composite is accurate. So the failure mode can be analyzed in theory to validate the veracity and reliability in experiment. Furthermore, the model can also be extended to simulate the impact behavior of the 3D woven composite structures.