The Parametric Analysis For Adhesively Bonding Patch Repaired Composite Structure Based On Progressive Damage Theory

Because of their high specific strength and specific stiffness,good corrosion resistance and good capability of fatigue resistance,advanced composite materials have been widely used in aerospace industry. With the improvement of the design method and development of the manufacturing process,the material performance of composite improves significantly,and its cost begins to compete with the traditional metal materials. And so, the technologies of composite structure repair and non-destructive detection have become the important direction of the research of composite material. This paper mainly studies the analysis methods of adhesively bonding patch repaired composite laminates.First of all,a finite element model of composite laminates has been established based on three-dimensional progressive damage theory in this paper. Using ANSYS parametric design language(APDL),the three dimensional Hashin criterion is wrote as failure criteria,considering four basic failure modes of matrix cracking,matrix fiber cutting,layering,and fiber breakage, and degradation criterion uses fixed material stiffness reduction factor. Finite element calculation result tallies well with the test data,to verify the effectiveness of composite material three-dimensional progressive damage model in this paper.Secondly,the paper implemented two finite element models of adhesive model,respectively based on continuum damage mechanics and the theory of maximum shear stress,supposing that the damage in the adhesive layer is isotropic. To determine the high reliability of two models, through comparison of the calculated results and test data. This article applies the adhesively bonding patch repaired model based on continuum damage mechanics.Thirdly,the high stress concentration areas of adhesively bonding patch repaired model are summed up,through analyzing the stress distribution under the uniform tensile load.Fourth,Based on three-dimensional progressive damage theory, the adhesively bonding patch repaired models with different patch sizes are established. Three kinds of overall failure forms of adhesively bonding patch repaired mode are summarized, by analyzing the ultimate damage situation. At the same time,the adhesively bonding patch repaired models with different adhesive parameters, such as patch thickness,patch shape and patch material,are established,in order to obtain the better parameters of adhesive.Finally, the better suitable parameters of adhesive thickness, adhesive material, are obtained by analyzing the damage propagation and the ultimate strength of adhesively bonding patch repaired models with different parameters of patch.