Experiment And DEM Simulation On The Viscoelastic Mechanical Behavior Of Rubber Bonded Particulate Material

In this paper,the discrete element method(DEM)is used to simulate the viscoelastic properties of rubber-bonded particulate material,and is verified by comparing the simulation results with experimental data.By changing the loading rate and the arrangement of particle units in the model,the macro properties of the rubber-bonded particulate material at different strain rates and different particle arrangements are simulated.The results of the study are of great significance to the design and mechanical properties analysis of rubber-bonded particulate material.The main results and conclusions include:1.The rubber-bonded particulate material specimens with regular square particle arrangement and hexagonal particle arrangement and random particle arrangement are fabricated.The stress relaxation curves under constant tension and the tensile stress-strain curves at different strain rates are obtained.Due to the influence of lateral deformation and internal damage,the stress value of the square array specimen increases with the increase of the number of columns in the stress relaxation test,and the equilibrium stress decreases.2.Burgers’ viscoelastic model is used to characterize the mechanical properties of the tested rubber-bonded particulate material,and the model parameters are determined through curve-fitting with the stress relaxation data,and the stress relaxation curves of each sample calculated by Burger’s model are consistent with the experimental results.3.The rubber binder is represented by the micro-scale Burgers’ viscoelastic bond model at contacts between the disk elements,the parameters of which are calculated from the macro-scale Burgers’ viscoelastic model of the tested specimens.The stress relaxation curves and tensile stress-strain curves are obtained using the discrete element models,and the model predictions are compared with the experimental results.It is shown that the discrete element model predictions are consistent with the experimental results for the specimens with regular particle arrangements,but the Burgers’ model parameters fitted from the stress relaxation data cannot accurately represent the strain-rate dependence of rubber binder under high strain-rate deformation.4.The damage function of Burger’s model parameters in the process of tensile fracture of rubber bonded particles is established.Based on the damage model,the particle flow code in two dimensions(PFC2D)is used to simulate the damage.The results show that the method of discrete element can be used to simulate the mechanical response of fracture.