Analysis Of Interlaminar Stress In Composite Laminates With A Hole Using ABAQUS

Carbon fiber composites are widely used in military industry,automotive,aerospace,sports equipment,civil engineering and other fields due to their high specific strength and corrosion resistance.When the composite laminate with a hole is subjected to in-plane tensile load,large interlaminar stress is generated near the free edge of the hole,causing delamination,degumming and premature failure of the laminate.Therefore,studying the magnitude and distribution of interlaminar stress has great significance for design optimization and failure prediction of composite laminates.In this paper,for the T300/epoxy laminate with a circle hole containing typical layer angles loaded in-plane,the finite element analysis software ABAQUS is used to analyze the interlaminar stress.The main contents are as follows:(1)The tensile test of the composite laminate with a hole was carried out,and the surface displacement field and strain field during the tensile process was determined based on the digital image correlation method.When the tensile displacement reached 6.54 mm,the test piece broke at the opening hole and severe delamination occurred,indicating that there was a large interlaminar stress at the edge of the hole.The displacement field and strain field measured by the DIC method began to form a stable distribution when the tensile displacement was about 5 mm,and the recorded cloud image was used as the basis for the subsequent verification of the finite element model.(2)A solid-based finite element model is established.The model is simplified by symmetric boundary dondition and shell-solid coupling constraints.The type of elements and the number of elements in each layer through the thickness direction of the model is analyzed and compared.When the element type adopts the quadratic reduced-integration element C3D20 R,and the number is 4,the model can balance the accuracy and calculation efficiency.(3)A model based on cohesive element is established.The cohesive element is used to simulate the interlaminar interaction and output interlaminar stress.The element type and the number of elements in each layer through the thickness direction of the model are discussed.When the element type adopts the Incompatible element C3D8 I,and the number is 2,the model can reach the precision demand.(4)Comparing the surface displacement field and strain field measured by the digital image correlation method with the finite element analysis results of the two models,and comparing the circumferential direction and the radial interlaminar stress distribution near the hole edge obtained by the two models,verifying the validity of the two models.(5)Use the finite element model based on cohesive element to study the interlaminar stress of near the hole at circumferential direction,radial direction and through the thickness direction,and obtain the distribution characteristics of interlaminar stress.