| The use of silicon carbide particle reinforced aluminum-based composite materials has great potential in the aerospace field due to their excellent properties.as their high strength and lightweight characteristics make them widely used in supporting components such as shafts and beams.However,fatigue damage during their application is inevitable.Currently,research on the fatigue behavior of materials mainly focuses on uniaxial tension or compression situations.However,engineering support components are also susceptible to shear loads,for example,beams usually experience transverse forces that produce shear deformation.Therefore,research on the shear load of materials is also of significant importance.In this paper,we conducted uniaxial tensile,uniaxial shear,and cyclic shear experiments on SiCp/2A14 aluminum alloy composites materials prepared by stir casting.Then,based on the GTN model,we established a shear constitutive model applicable to composite materials.We determined the parameters based on experimental results and established the constitutive model of SiCp/2A14 aluminum alloy composites,and verified the reliability of the model.The main research contents of this paper are as follows:(1)A series of mechanical experiments were conducted on SiCp/2A14 aluminum alloy composites.Uniaxial tensile experiment was carried out on SiCp/2A14 aluminum alloy composites material using a universal testing machine,and uniaxial shear and cyclic shear experiments were conducted on the SiCp/2A14 aluminum alloy composites with three different SiC contents on a double-bridge cyclic shear machine to obtain experimental data.These experiments were conducted at room temperature and accurately measured with the help of DIC three-dimensional speckle system.Through the experiments,the yield strength,fracture elongation,and fatigue life of SiCp/2A14 aluminum alloy composites material at room temperature were obtained.(2)Mechanical experimental study of SiCp/2A14 aluminum alloy composites under different strain amplitudes and SiC particle volume fractions.By single tensile experiment,and build shear test study materials in mechanical behavior under loading ways of the two,first through one-way shear experiments using an external style Angle encoder,with DIC system to measure the equivalent strain of materials in the process of experiment,the sample Angle beta and the relationship between the equivalent strain,then under cyclic loading,The stress-strain curves of the materials were obtained and studied.(3)Establishment of the constitutive model for composite materials.In this paper,a homogenization model for composite materials was first established by analyzing it as a homogeneous material.Then,based on the GTN model and a fatigue model with shear equation correction,a micro model of homogeneous metal matrix composite material was used as a framework in which pore nucleation and growth factors were considered to more accurately describe the mechanical behavior.Finally,the parameters in the constitutive model were identified by inverse analysis of experimental data.(4)Numerical simulations were performed on the constitutive model,and the simulation results were compared with experimental results to demonstrate that the model can predict the tensile behavior of SiCp/2A14 aluminum alloy composites with three different SiC percentage contents.The program was then extended to simulate the results of SiCp/2A 14 with different SiC contents under the same strain amplitude using the method of controlling variables.In addition,the cyclic shear behavior of SiCp/2A14 with the same SiC percentage content under different strain and stress amplitudes was simulated,and the model was validated against experimental cyclic curves to verify its feasibility in predicting the fatigue behavior of SiCp/2A14 aluminum alloy composites. |
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