Experiment And Numerical Simulation Of Mechanical Properties Of Carbon Fiber Reinforced Aluminum Alloy Laminates Prepared By Molding

Carbon Fiber Reinforced Aluminium Laminates(CARALL)are considered to be the third generation fiber-metal laminates.Because of their high specific strength and specific rigidity,they are excellent Anti-fatigue and impact resistance,they has great development potential in the field of aerospace and automobile lightweight.Therefore,in order to deeply understand their mechanical properties and accelerate the popularization and application of CARALL,it is particularly important to study the basic mechanical performance parameters of CARALL,and their failure behavior and failure mechanism during uniaxial tensile and bending loads.The main content and conclusions of this article include:(1)The principles methods of Abaqus/Standard and Abaqus/Explicit solver is analysied.Abaqus/Standard uses the Newton-Rapshon method to solve the problem.Through continuous iterations until the residual error is less than the set value,the composite material failure analysis is performed.To solve the method problem,it is necessary to introduce the viscosity regularization coefficient and the hysteresis damage to ensure the convergence.Abaqus/Explicit uses the central difference method to solve nonlinear problems,replacing the derivative of displacement with time by finite difference,expressing the velocity and acceleration in the equation of motion with a certain combination of displacement,and then transforming the problem of solving ordinary differential equations into algebraic equations Although the computational cost is relatively high,the problem of solving the group has no convergence problem,and there is no need to introduce a viscosity regularization coefficient to delay the damage,which is more accurate by comparison.(2)The microscopic morphology of the fracture of the uniaxial tensile and three-point bending specimens were observed with the aid of a scanning electron microscope.Under the uniaxial tensile load,the 0° layer fiber bundles of CARALL were mostly broken,and some of the fiber bundles were pulled out.The displacement curve exhibits bilinear behavior before the laminate reaches the ultimate strength,and suddenly drops to the lowest point after reaching the ultimate strength;under the three-point bending load,the layers above the CARALL neutral layer have no obvious damage.The failures are mainly concentrated under the neutral layer.The main failure modes are: fiber fracture,matrix cracking,and interlayer delamination.The load-displacement curve also shows bilinearity before reaching the ultimate strength,and after reaching the ultimate strength,the damage evolution stage shows There are three more obvious breaking points in the stepped decline.(3)The Abaqus model and the VUMAT model predict the damage cloud map of each layer group in CARALL uniaxial tension roughly.The bilinear behavior of the load-displacement curve and the capture of the fracture point before the laminate is relatively accurate.For the failure of the 0° layer fiber The behavior prediction VUMAT shows great potential,and the maximum strain and minimum strain criteria are introduced as auxiliary element deletion criteria.It predicts that the damage cloud map will not have a large deformation at the fracture,which is closer to the experimental macroscopic observation results.There are also some differences in the results of the two models predicting the damage cloud maps of the three-point bending of the laminate.The Abaqus model uses the 2D Hashin criterion as the carbon fiber failure criterion,ignoring the effect of the out-of-plane load component on the carbon fiber failure behavior.VUMAT predicts the bottom of the neutral layer.The fracture locations in the 90° layer were concentrated and did not extend,which is more consistent with the results of scanning electron microscopy.VUMAT calculated that after the laminate enters the damaged state,the three-point bending load-displacement curve also has three fracture points as in the experiment.This paper analyzes the damage cloud images of each layer below the neutral layer at the three fracture points to further understand the failure behavior and failure mechanism of CARALL when subjected to bending loads.(4)Based on the prediction results,the Abaqus model and VUMAT model are in good agreement with the experiment in predicting the failure behavior of CARALL.If the focus of CARALL is mainly on the ultimate load strength,the Abaqus model can also make more accurate predictions,and the calculation efficiency is high,and the user does not need to rewrite the failure criteria;and if the focus is on the failure behavior of the entire loading process with CARALL,Although the calculation cost is relatively large,the VUMAT and the measured results are more accurate.