Study On Penetration Resistance Of Cement-based Functionally Graded Materials

With implementation for our country's normative management of the territorial sovereignty of the distant sea and the formulation and implementation of the marine development strategy,the construction of a comprehensive supply base and outpost in the remote island will be the first step in the remote sea strategy.The traditional building materials used in the marine climate haven't meet the conditions of the remote island service,in which the protection of impact,thermal insulation and other properties,it has seriously restricted large-scale construction,management and resource development of China's sea.The material studied in this paper is a cementitious composite material composed of a functionally gradient materials.The development of a new cementitious functionally gradient materials is set to against the impact and thermal insulation properties of a material,which is to resist the remote island harsh environment and to meet the island construction requirements.It's relevant performance need to explore urgently.In the paper,we mainly study the anti-penetration performance of the thermal insulation integrated gradient material used in the construction of the island.First,the thickness distribution of each component in the functionally gradient material is determined and optimized.LS-DYNA,which is finite element software,numerically simulate the projectile penetration of the target,and based on the simulation results to determine the functionally gradient materials of the advantages and disadvantages of anti-penetration properties.The main contents and conclusions of the paper are as follows:(1)In the paper,the performance of the transition layer of the functionally gradient material is predicted by using the linear mixed law in the microscopic mechanics,and the relevant mechanical parameters of the transition layer are determined.The matrix layers and transition layers of the functional gradient materials are the model of HJC,and the bullet is described by Johnson-Cook constitutive model.By using the numerical calculation of LS-DYNA software,which draw the predicted transition layer of functional gradient material is reasonable or not,and also verify that the HJC constitutive model is reliable from the side.(2)The optimum thickness ratio of each component of the material studied in the paper was determined.The material is divided into 5 layers along its thickness direction.The outer layer,the middle layer and the inner layer are different materials.The interface between the outer layer and the middle layer is the transition layer,and the interface between the middle layer and the inner layer is other transition layer.In the paper,the elements in the transition layer are distributed according to a certain percentage of the volume in the numerical simulation,so that the performance of each component can be changed continuously in the same direction.Then,the composition of each layer is set to different thickness,and the performance and composition of each layer change with the thickness change,which is used as a calculation condition.In the paper,the practical purpose of the functional gradient structural material is mainly,so set the total thickness of the material unchanged.By changing the thickness of each functional layer and taking the anti-penetration performance of the material as the evaluation standard,the optimal thickness ratio between the functional layers is finally selected.After determining the optimum thickness of the functional gradient material,which to change the thickness of the middle layer and numerically to simulate the buffer invading the gradient material target.According to the material penetration resistance as the evaluation criteria to finally select optimal thickness ratio of functional gradient materials and optimize the volume components of each component of the material.(3)By using LS-DYNA explicit dynamic analysis software to calculate the simulated optimal thickness ratio of the material through the numerical simulation calculation,which analyze the functional gradient structural materials' damage,depth,speed-time curve.Through the comparison and analysis of the traditional ordinary concrete materials,the advantages and disadvantages of the anti-penetration performance of the functional gradient structural materials are evaluated,and the functional gradient materials are used to provide some theoretical support for the construction of the island project,and also provide reference for the next target experiment.