Mesoscopic Progressive Damage And Failure Analytic Of Self-lubricating Fabric Liner

Fabric self-lubricating joint bearings are widely used in aerospace and other fields.The self-lubricating fabric liner is the key material of aviation joint bearings,which has a great impact on the bearing’s impact resistance and reliability.Analyzing the mechanical mechanism of the liner is the bottleneck demand for the development of high-performance self-lubricating joint bearings.A large number of tests have proved that the failure and damage morphology of the liner are reflected in the meso-scale,so the damage evolution mechanism can be better revealed from the meso-scale.In this thesis,starting from the meso-scale,the mechanical analysis model and theoretical method of the self-lubricating fabric liner under the condition of out-of-plane compression were studied through the research method combining test and numerical analysis,and then the mechanical state evolution and damage failure mechanism of the component materials were revealed.The specific work content is as follows:According to the national standard experimental method,an experimental method of out of plane compression was designed for self-lubricating fabric liner,a single layer woven composite material,and the meso-geometric structure parameters and damage and failure morphologies of the liner were obtained by microscope observation.Based on the mesomechanics research method,the stiffness and strength of the fiber bundle were calculated by using the bridge model formula,and the progressive damage evolution of the fiber bundle was studied according to the original properties of the fiber and the matrix.Based on the Fortran,the VUMAT subroutine was written to carry out the secondary development of the calculation software.The damage evolution models of the matrix and fiber bundle/matrix interface were established respectively.The representative volume unit(RVE)model was extracted and established,and the periodic boundary conditions of RVE model were applied through the secondary development of the calculation software by writing a Python script.A finite element model was established to study the damage evolution of self-lubricating fabric liner under external compression.The results show that the numerical analysis model considering the interface damage failure is in good agreement with the experimental data,which can better simulate the nonlinear mechanical response of the liner under load condition.The strength of the interface layer has a great influence on the overall bearing capacity of the liner and the damage state of the component materials.The final loss of bearing capacity of the liner was due to the shear fracture of the aramid fiber bundle in the interleaved zone,which was preceded by a large area of matrix and interfacial layer failure.