Numerical simulation of the effects of fiber volume fraction on thermal residual stress and damage of Cf/Al composites
For unidirectional carbon fiber reinforced aluminum composites(unidirectional Cf/Al compos-ites)prepared by vacuum pressure infiltration,a meso-mechanical finite element model was established based on the constitutive model of matrix ductile damage and interface cohesive zone.Combined with ther-mal expansion experiments,the distribution and evolution of thermal residual stress and damage during the cooling process were studied,and the influence of fiber volume fraction was analyzed.The results show that the meso-mechanical unit cell finite element model can effectively simulate the macro-thermal expansion deformation behavior and transverse tensile mechanical properties of the composities,which can be used to predict the thermal residual stress and damage.After the preparation of composites,the matrix mainly bears thermal residual tensile stress,while the fiber mainly bears thermal residual compressive stress.With the increase of fiber volume fraction,the degree of concentration of residual tensile stress in the matrix-rich zone increases gradually,and the residual compressive stress in the fiber decreases significantly.The matrix damage originates from the matrix-poor zone near the interface;the higher the fiber volume fraction is,the earlier the initial damage of the matrix occurs during the cooling process,and the greater the final damage degree.When the fiber volume fraction is large,the interface near the matrix-poor zone will be damaged,and the interface damage occurs after the matrix damage.
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