Experiment-based Hybrid-inverse Method And Its Application To The Study On Properties Of Composites

With the rapid development of materials science, the advanced materials andstructures have possessed more and more functions as well as complicated properties.However, it is usually difficult in determining these properties by means of simpleexperiment or numerical analysis. The characteristic of the hybrid experimental-numerical method lies in preserving the advantages of experiments and numericalanalyses. Presently, the functions of the hybrid method, nevertheless, still have someremarkable limitations. From the point of view technically, this method belongs to thedirectly mixed classification all the same. Therefore, to develop study of the newhybrid techniques, which can be suitable for solving nonlinear, multi-parameterproblems and research on the properties of complicated materials in engineering, is ofgreat importance scientifically and of potential in engineering applications. Thispaper puts emphasis on the following two aspects: study of the new hybrid methoditself; application of new hybrid techniques to the study of nonlinear mechanicalproperties of composites. A novel experiment-based semi-loop hybrid/inverse method, which introducessome new solution techniques of inverse problems, is presented in this paper. Incontrast to previous directly mixed hybrid methods, the present method integratesexperimental test and numerical analysis and the solution of inverse problems andmechanical models systematically. Due to the facts that it is based on propermechanical model and makes plenty of experimental data and results as constraintconditions and referred target, the present method can succeed in identification andpick-up of multi parameters in complicated problems as well as hybrid solution ofnonlinear problems. This paper introduces, respectively, gradient-based optimizationmethod, artificial neural network method and genetic method into practicalhybrid/inverse procedures. Also, the technical characteristics and applicability and soon of three methods mentioned above are analyzed and discussed. This paper initially applies this experiment-based hybrid/inverse method to thestudy of mechanical properties of the interface with irregular shape of practicalmulti-phase composites. Based on the results of the microstructure obtained from fineexperiment and in conjunction with theoretical model taking interfacial damage andfailure into account and numerical FE-simulations of interfacial failure in themicrostructure, the relevant mechanical parameters in the damage and failure processof actual metal-matrix composite are inversed quantificationally and the difficulty ofdirect measurement of interfacial properties of actual materials is overcome. Inaddition, this method is also used to inverse identification of nonlinear mechanicalproperties for components of composite. Taking a bimetallic sheet as research object,the experiments are designed. Based on the continuous nonlinear mechanicalresponse obtained from experiments and in conjunction withthe constitutive model ofelasto-plasticity and FE numerical analysis, the elasto-plastic mechanical propertiesof the two metals constituting the bimetallic sheet are, respectively, identified. It isverified that this method is applied successfully to the inverse identification ofelasto-plastic properties of practical materials.