Numerical Simulating Workability Of Fresh SCC Flow Based On DEM

Self-compacting Concrete(Self-Compact Concrete,referred to as SCC)due to its high fluidity and good casting capability,is widely used in practical engineering.Usually on the performance of self-compacting concrete work is detected by methods of field experiment,indoor test,not only waste the time,manpower and material resources,but also to the properties of self-compacting flow in the template is not good to control,so the method of numerical simulation is necessary for performance of self-compacting concrete.Because the self-compacting concrete is component size(from the nano scale to centimeter scale)there were significant differences of anisotropic materials.So this paper use the Discrete Element Method,of various characteristics of self-compacting concrete is simulated from the microscopic.Firstly,the fresh selfcompacting concrete discretization,then design the user-defined contact model,through the indoor test,the neural network,genetic algorithm,the micro parameters of numerical simulation method combining the contact of the discrete element model of inversion,The main contents of this paper are as follows:(1)On the basis of summarizing the basic principle of particle flow,with the introduction of "excess mortar theory",the SCC is discretized into the coarse aggregate unit of the space mortar unit and the excess mortar,which are expressed by the sphere particles,furthermore,the simplified particle element size and physical properties are modified.(2)To simplify the analysis of "liquid bridge model" theory,and combining the nonlinear deformation of the spring Hertz theory,using PFC3 D software platform for the custom model to generate discrete element contact model file,and use examples to prove the correctness of the user to compile a custom model.This model can be used to characterize the effect of mortar on coarse aggregate,and discrete element numerical simulation model was established according to indoor experiment.(3)The configuration of self-compacting concrete,to detect the SCC performance by using indoor test,through neural network,genetic algorithm to establish experimental and simulated values of the mathematical model of nonlinear mapping,getting the inversion parameters,then using the forward way for numerical calculation,the numerical solution obtained by the inversion error analysis,the results show that the inversion result is suitful.