Meso-macro Scale United Mechanical Model Of Asphalt Mixture Based On UMAT Subroutine Development

Asphalt mixture is a multiphase composite material,its macroscopic mechanical properties are greatly influenced by material mesoscopic characteristic.However,for convenience of practical engineering application,using the simplified model to design the asphalt pavement structure and ignoring the material inhomogeneity,pull pressure difference,the influence of the mesoscopic damage accumulation,etc.Under such circumstances,the design parameters of the asphalt pavement structure have certain irrationality and cannot meet the practical requirements.Therefore,mesoscopic material properties of asphalt mixture and its macroscopic mechanical response must be united,which makes asphalt pavement engineering design in accordance with the real situation,so as to achieve goals.This article main research content is as follows:At first,the mechanical model and material characteristic parameters adopted by this article are introduced.Choose equivalent stress,plastic flow rule and strengthen standards in conformity with the mechanics response of asphalt mixture,obtain the corresponding transverse isotropic matrix and damage factors through the aggregate orientation parameters and material strain development respectively,build meso-macro scale asphalt mixture unified mechanical model.Secondly,based on ABAQUS software platform for material UMAT subroutine of the model development.Build a subroutine call and debugging module,and carries on the judgment of material deformation stage,through the return mapping algorithm and Taylor series expansion and iteration to obtain the equivalent plastic strain increment,realized the material stress state and the real-time updating of Jacob than matrix,at the same time,by introducing the vector form of transverse isotropic parameters and single scalar damage factor,in the form of fine-unified macro mechanics model was analyzed and deduction and programming.Third,to verify the effectiveness of the subroutine,the influence of various parameters were analyzed.Compared the UMAT subroutine and software bring material calculation results of the same model,and according to the control variable method to obtain the hardening parameter,transverse isotropic parameters and damage,the effects of parameters on the material mechanics response of asphalt pavement structure design,provides the corresponding Suggestions.Finally,proved the practicability of a subroutine,obtained the related parameters of surface structural response.Was observed through indoor uniaxial compression tests the material parameters needed for the subroutine,subroutines in the practical application feasibility is verified,and the simulation on the basis of road surface structure,the orientation of the impact parameters on the mechanical response of the road.As you can see,this paper successfully adds the meso-scale configuration and damage evolution features into the material model,obtain the corresponding mesomacro mechanics model,which can be more comprehensive description of mechanical properties of the asphalt mixture,and provided the corresponding advice asphalt pavement structure design based on material microstructure characteristics.