Dynamic Responses Of 3-D Hybrid Knitted Composite T-beam Under Transverse Impact

This paper report the dynamic responses of 3-D hybrid knitted composite T-beam under different speed impact.The hybrid knitted composite is composed of two knitted fabrics:biaxial warp knitted fabric and interlock knitted fabric.The dynamic responses of the hybrid knitted composite T-beam under transverse impact were investigated with a modified split Hopkinson bar(SHPB).The T-beams made of the 3-D hybrid knitted composite were also tested with MTS 810.23 material testing system for characterizing the quasi-static indentation behavior,and employed with a split Hopkinson pressure bar(SHPB)apparatus for investigating the transverse impact responses.The impact load-displacement curves will be obtained to analyze the energy absorptions of the T-beam under impact loading.The influences of impact velocity and flange height on the impact damage of the T-beam will also be presented. A unit-cell model of the hybrid knitted composite will be established to describe the constitutive equation and failure criteria.A user-defined material subroutine VUMAT (Vectorized User-defined Material Subroutine)will be connected with commercial FEM code ABAQUS/Explicit to calculate the impact responses.The comparisons between experimental and FEM will be taken to validate the unit-cell model.We expect such a unit-cell model could be extended to the design of other hybrid knitted composite structures.