Thermal Residual Stress And Impact Response Of Carbon Fiber Reinforced Magnesium Alloy Based Composite Laminates

As a new type of composite laminate,the plain woven carbon fiber reinforced magnesium alloy(WFRP/Mg)laminate both has good corrosion resistance and fire resistance of metal alloys as well as impact resistance and fatigue resistance of woven fiber composites.So it has great application prospects in the fields of aviation industry and ship armor.This paper is focused on the impact resistance of laminates subjected to low velocity impact with considering residual stress.In addition,the damage failure mode and dynamic mechanical response process of the laminate are also analyzed.The plain woven layer has typical multi-scale features and it is very important to predict basic mechanical properties and transfer parameters accurately based on microscopic unit model.Based on the continuum mechanics and homogenization method,the basic thermal and mechanical parameters of the composites are predicted through three different structural scales: micro scale,meso scale and macro scale.Periodic displacement and temperature boundary conditions are applied by Python language to ensure that the stress,strain and heat flux of the model are continuous.At the same time,the circular graphene nanoplates(GNPs)was randomly added to the microscopic model.The results show that GNPs can enhance the elastic modulus and thermal conductivity,but reduce the equivalent thermal expansion coefficient of the composites.Hot pressing induced residual stresses have great influence on the properties and service life of laminates.It is necessary to study the influence of key factors on the value and distribution of residual stresses to reduce residual stresses and optimize their distribution.Based on the ABAQUS/standard platform,this paper establishes a thermo-chemical model and a static model to reveal the evolution of temperature field,cure field and residual stress field.The simulation results showed,there exists a strong coupled effect between the cure field and temperature field of the resin matrix.The cure heat and the difference in heat transfer capacity leads to uneven distribution of internal temperature and cure field of the laminate,which would affect the evolution of residual deformation;For different curing kinetic models,there is also different curing process.This will affect the distribution and value of residual stress inside the laminate;For the same resin matrix,the higher the curing temperature,the greater the cure shrinkage of the resin and the bigger the residual stress value inside the laminate.In order to investigate the low-velocity impact response of WFRP/Mg laminates with considering residual stresses,a meso-macro multi-scale model is first established in this paper.Johnson-Cook(J-C)constitutive and damage models are adopted for the magnesium alloy.The 3D-Hashin initial damage criterion and Mises failure criteria are applied to the warp/ weft fiber bundles and the resin matrix,respectively,which are implemented by the material subroutine VUMAT compiled by Fortran.The linear continuous stiffness degradation is used to characterize the damage evolution process of the material.The results indicate that the fiber bundles breakage and the matrix cracking form can be clearly seen in meso-macro multi-scale model.Meanwhile,compared with the laminate with orthogonal plies(UFRP/Mg),laminate has a lower initial stress of fiber layer,smaller damage area and lower peak load,but has a larger impact displacement because of good ductility.Finally,a macro model of woven/unidirectional carbon-fiber reinforced Mg alloy composites(UWFRP/Mg)is developed,and the damage is predicted by the Tsai-Wu criterion in the macroscopic region.The results show that the damage area,maximum deflection,peak load and energy absorption of UWFRP/Mg laminates are all increased with the increase of impact velocity.