Analysis Of The Influence Of The Uncertainty Of Constitutive Model And Material Parameters On The Mechanical Properties Of Rubber Composites

In this paper,the mechanical properties of rubber reinforced with particles and rubber composites reinforced with short fiber and rubber concrete are experimentally research and numerically simulated with rubber material constants obtained by using different strain energy function and different test conditions.The influence of the uncertainty for the rubber constitutive model and material parameter on the mechanical properties of rubber composite is discussed,and the effect of rubber material as matrix and reinforced phase for composites on reinforcement and toughening are fully analyzed,which can provide theoretical basis for the widely application of the rubber composites.At first,based on the theory of continuum mechanics,the selection principle of strain energy function of rubber material and the establishment method of hyperelastic constitutive equation of rubber material are summarized.the advantages and disadvantages of the constitutive models for rubber materials expressed by different strain energy function are analyzed.The influence of uncertainty of constitutive model and material parameters on the effective mechanical properties of rubber materials is explored,which provide beneficial basis to select the correct strain energy function for rubber composites.Then,the finite element model of rubber composites reinforced ceramic particle is established,using the generalized hooke's law,the strain energy method,the Mori-Tanaka,Halpin-Tsai,modified Halpin-Tsai and homogenization,the effects of size,percentage,initial elastic modulus and other parameters of ceramic particles on the effective mechanical properties for composite are studied.The results confirmed that the modified Halpin-Tsai method comprehensively considers the advantages of the combination for the classical theory and the finite element method,and the homogenization method overcomes the cumulative error in the finite element calculation through statistical average,so the results of the two methods are more reliable.The influence of uncertainty of constitutive model and material parameters for rubber on the effective mechanical properties of rubber composites reinforced particle is discussed.Based on the quantitative index of normal distribution,it is proved that the Yeoh model is suitable for rubber composites reinforced ceramic particle.Thirdly,considered of the constitutive relation of large deformation for rubber,two-dimensional and three-dimensional finite element model for rubber composite reinforced with short fiber with different orientations and aspect ratios are built by Ansys.The effective elastic modulus of rubber composites reinforced with short fiber is calculated by the finite element method,and compared with those from the classical theory method,the more accurate and reliable prediction results are obtained,which proved that the three-dimensional finite element model is irreplaceable.The influence of uncertainty of constitutive model and material parameters for rubber on the equivalent stress of rubber composites reinforced particle is discussed,and the reasonableness of the Yeoh model is proved.Fourthly,the rubber concrete is prepared by adding rubber particles with different size and proportion into ordinary concrete,then the test for compressive strength and flexural strength are respectively carried out,the cubic compressive strength,axial compressive strength and flexural strength are obtained,then compared with those calculated from the finite element numerical simulation method,the influence of uncertainty of constitutive model and material parameters on the above parameters is analyzed.To reduce the decline of the strength for rubber concrete and improve the toughness and durability for rubber concrete,the rubber particles are treated with water and sodium hydroxide solution and then mixed into concrete,then the effect of the modified rubber particles on the mechanical properties of rubber concrete is analyzed,it is determined that optimum concentration of sodium hydroxide soaking solutionFifthly,in order to make full use of the strength of rubber concrete,the damaged rubber concrete are set up for an hour and the compressive performance test are carried out.The results show that the second compressive strength of damaged rubber concrete is greater than that of the first compressive strength when the amount of rubber particles is larger,which proves that the timeliness is favorable to improve the compressive strength of the rubber concrete.