Mechanical Behavior Characterization Of Woven Fiber Reinforced Laminates Under Complicated Stress State

With the increasing demand for vehicle lightweight design,woven fiber reinforced laminates has attracted extensive attention of automotive industry,thanks to its excellent mechanical properties.However,its complicated anisotropy and multiple failure modes bring difficulties to finite element simulation.In this paper,aiming at woven fiber reinforced laminates,the following four aspects are studied.The complex mesoscopic structure and special mechanical behavior of woven fiber reinforced laminates have brought many difficulties to its mechanical test.In order to calibrate composite material model,mechanical test methods suitable for woven fiber reinforced laminates are studied firstly.It is shown that mechanical test standard ASTM D3039 and ASTM D3410,which are used for obtaining tensile properties and compressive properties of uniaxial fiber reinforced polymer respectively,are also suitable for woven fiber reinforced laminated composites,but for in-plane shear properties,strain field analysis indicates that Iosipescu shear test can provide a strain field which is the closest to pure shear strain state in the four test methods conducted.Therefore,Iosipescu shear test is more suitable for obtaining shear properties of woven fiber reinforced laminates.The energy absorption characteristics and shear properties of plain woven carbon fiber reinforced laminates and biaxial carbon fiber reinforced laminates are then compared.Axial impact crushing tests are conducted on corrugate specimens made of these two types of composite.Test results show that specimens with different stacking sequence made of plain woven fiber reinforced laminates have higher energy absorption efficiency and better stability.Moreover,plain woven carbon fiber reinforced laminates has better shear properties.Therefore,plain woven carbon fiber reinforced laminates are more suitable for significant parts on vehicle.Mechanical test methods that are suitable for woven fiber reinforced laminates are then conducted on plain woven carbon fiber reinforced laminates to determine the input of composite material model MAT₀58 in LS-DYNA,which should be the right model for woven fiber reinforce laminates simulation.In this paper,a single layer modeling method and a multi-layer modeling method are used to build the simulation model of corrugate specimen crushing test,and a method to estimate the mechanical parameters between layers in multi-layer method is proposed.The material model can give a precise prediction on crash test of?0°?₆ laminates when using multi-layer modeling method,but neither modeling methods can give an accurate prediction on?45°?₆ and?0°/45°?₃laminates tests.Due to the shortcomings of the existing composite model in the simulation of plain woven fiber reinforced laminates,user defined subroutine VUMAT in Abaqus is then adopted to write a composite material model which is suitable for plain woven fiber reinforced laminates.At present,the subroutine can successfully predict the behavior of the material in 0°uniaxial tension,±45°uniaxial tension and punch test,but cannot be used for simulating axial crushing of corrugate specimen,which mainly may due to the lack of failure induction mechanism.