Finite Element Analysis Of Shear Stiffness Of Composite Laminates With Non-ideal Transverse Matrix Cracks

Because of the manufacture and use of the environment,fiber-reinforced composite laminates inevitably have transverse matrix cracks,these cracks also affect the stiffness of laminates.Due to the anisotropy of composite materials,it is difficult to analyze the stiffness degradation of laminates with transverse matrix cracks,especially the degradation of shear modulus of laminates by transverse matrix cracks.In this paper,the effects of non-ideal transverse matrix cracks and closed crack surface bridge factor on shear stiffness of composite laminates are discussed.In this paper,the finite element method is used to discuss the decrease of shear modulus of laminates.The finite element model of the shear stiffness of composite laminates with the ideal transverse matrix composite laminates is verified and evaluated by the existing theoretical and experimental model of the ideal transverse matrix composite laminates.Based on the finite element model,the bridge factor is introduced to describe and evaluate the shear modulus decreases regularly of the orthogonal symmetry laminates with non-ideal transverse matrix cracks and the Non-orthogonal symmetric laminates with non-ideal transverse matrix cracks.The finite element results show that the non-ideal transverse matrix cracks have a significant influence on the degradation of the shear modulus of laminates in the orthogonal symmetry laminates with non-ideal transverse matrix cracks,and there is a positive correlation between the bridge factor and the lower limit of shear modulus.The decrease of shear modulus tends to be gentle with the layer Angle increases in the Non-orthogonal symmetric laminates with non-ideal transverse matrix cracks.It is necessary to discuss the decrease of laminates stiffness for the safety design of fiber reinforced composites.