Research On Mechanical Properties Of High Temperature Alloy Honeycomb Panels With Defects

Metal thermal protection structure mainly includes high temperature alloy honeycomb plate,high and low temperature heat insulation layer and a titanium alloy honeycomb panel,high temperature alloy honeycomb plate in the outer layer of MTPS,is to isolate the internal and external heat of the structure and subjected to the external loads on the aerocraft in the process of work,and in the process of service,it is inevitable to have different defects,so it is of great significance to study the mechanical properties of the non-defective and defective honeycomb plate.Firstly,the GH4099 foil is rolled into a corrugated plate by a gear roller,then the corrugated plate is connected to the honeycomb core by the resistance spot welding technology.And the honeycomb core is made by wire cutting,flat grinding,deburring and brazing.The defective honeycomb plate is made by the way of pre-buried defects.The quasi-static flatwise compression test and edgewise compression test are carried out on the prepared honeycomb plate to study the influence of surface-core connecting defect on the mechanical properties of the honeycomb plate,also the deformation process and yield stress of the non-defective honeycomb plate are analyzed.The defect of surface-core connecting defects has little effect on the flatwise compression performance of the honeycomb plate,The edgewise pressure strength of the longitudinal honeycomb plate is higher than the transverse honeycomb plate.In the research of the edgewise compression performance,the surface-core connecting defects are divided into node effect,single wall effect,double wall effect,and study the influence of these three types of defects on the edgewise compression performance of the honeycomb plate.Meanwhile,the process parameters of resistance spot welding of TC1 foil are optimized by BP neural network and genetic algorithm,which provides the basis for the preparation of the titanium alloy honeycomb plate.Finally,the processes of the flatwise and edgewise compression are simulated by Abaqus,in the simulation of flatwise compression,the peak value of stress appears in the middle position of two adjacent honeycomb side walls and spreads to both sides.The error between the simulated limit load and the experimental value is only 1.2%.In the simulation of edgewise compression,the overall stress distribution of the longitudinal honeycomb plate is uniform.At the end of the compression,the stress is concentrated on the upper and lower head,and the upper end of the panel produces the deformation bulge.The main thrust structure of the transverse honeycomb plate is the panel and the single wall,The peak stress at the junction of the double wall and panel is far lower than the connection between the single wall and panel,the peak stress of single wall is higher than the double wall,at the end of the compression,the stress is concentrated at the upper and lower pressure head.Because of its unique stress distribution characteristics,the upper end of the panel produces dimpled bulge...