Research On Hole Machining Technology Of Carbon-Carbon Composite Based On Water Jet

In recent years,with the maturity of carbon-carbon composite material preparation technology,there is a great demand for composite materials in the fields of Aerospace,national defense and military industry,and the rapid development of carbon-carbon composite material drilling technology in our country is followed by the market demand for carbon-carbon composite material whose higher processing quality is also required.But now the domestic carbon-carbon composite material hole technology is not particularly mature,it may cause great waste of resources and economic losses.Aimed at the disadvantages of expensive tools,serious wear,and easy delamination of materials in the machining of holes in carbon-carbon composite materials.Studying high-pressure water jets to make holes in composite materials can effectively reduce tool costs to reduce the problems caused by a large number of experiments,it is an inevitable choice to finite element software to simulate the jet punching process of carbon-carbon composites and optimize the jet processing technology.In this paper,the jet machining process of carbon-carbon composites is taken as the research object.The jet simulation model is established.The relationship between the parameters such as jet pressure,cutting speed and composite material delamination was analyzed by finite element analysis software ANSYS/LS-DYNA.Initial realization of finite element simulation of jet punching process of carbon-carbon composite laminates,the most suitable parameters for processing which did not affect the delamination were obtained,and the influence of each parameter on the processing results was analyzed.And the experiments under different jet processing parameters were carried out,the simulation results were verified.The main research contents of this paper are as follows:(1)Based upon the study of the failure model of carbon-carbon composites,the problem of material deformation in the punching process was analyzed.The mechanism of the jets was studied from the theoretical point of view.An impact force model of two-dimensional right-angle free jets was established.The jet force was derived theoretically.The calculation formula.(2)A simplified model of carbon-carbon composites was established.Based on this,a micro-model of the jet punching processing was established.Then the finite element software ANSYS / LSDYNA was used to simulate the jet pressure and cutting speed,The maximum stress of the material failure process and the stress versus time during the jet process are obtained,and the layered condition is determined by the amount of inter layer displacement at the location of the maximum stress.(3)The jet flow punching experiments of carbon-carbon composites were carried out using the jet parameters obtained from the simulation.Compared with the simulation results,the experimental results were analyzed to find the most important jet parameters affecting the layered defects.(4)The layered flaw detection and roundness analysis were performed on the hole processed by water jet,and the experimental results were compared with the simulation results under the same process parameters to verify the validity of the model.The purpose of this paper is to simulate the jet flow of carbon-carbon composites by finite element method,optimize the selection of processing parameters of water jet,improve the quality of the hole,and provide a new method for the processing of carbon-carbon composites.