Research On Near Edge/on Edge Low-velocity Impact And Compressive Residual Strength Of T300/69 Laminates

Because of their high specific strength,high specific stiffness,excellent fatigue strength,good corrosion resistance and low thermal conductivity,composite materials have been widely used in aerospace,high-speed trains and other fields.However,due to the particularity of composite structure,its impact resistance is relatively poor.It is inevitable that foreign materials(such as runway debris and falling tools)will be impacted outside the plane during manufacturing,operation,maintenance and maintenance.Although no obvious damage is found on the surface of the material,there may be delamination and debonding damage in the interior,which seriously reduces the comprehensive property of the material,and then have a serious impact on the safety of materials.There are many scholars who study the impact of laminated plate outside the center,but few researches on the damage caused by the impact of the near edge and the edge.Therefore,the paper studies the near edge,edge impact and residual compressive strength of T300/69 laminated plate,and the specific contents are as follows:Taking T300/69 laminate as the analysis object,different impact energy and thickness were selected to carry out the low speed impact and compression residual strength tests on the edge and the edge respectively.The damage characteristics,morphology,damage propagation process and compressive residual strength of laminates under the two impact types were compared and analyzed in detail.Based on the three-dimensional progressive cumulative damage analysis theory,the failure process of T300 / 69 laminates under near edge impact,edge impact and post impact compression was simulated by using the finite element software ABAQUS and the adapted VUMAT subroutine.The results of the simulation are compared with the experimental results from the three aspects of the depth of the pit,the damage state and the residual strength of compression caused by the impact,and the correctness of the numerical simulation is verified.At the same time,combined with the impact damage process of the laminate,the impact response,impact damage characteristics and mechanism of the laminate subjected to the impact of the near edge and edge are analyzed in detail,and the formation reason and expansion law of the fiber,matrix damage and delamination are fully revealed.