Analysis Of Microscopic Mechanical Properties Of EPS Concrete Based On Random Aggregate Model

EPS concrete is a kind of lightweight concrete material which uses polystyrene foam as light aggregate.Because of its good thermal insulation and seismic performance,it is widely used in engineering practice.At present,most of the research on EPS concrete is based on the experimental method,but considering that it takes a long time to study and the results obtained are closely related to the environment,the mechanical properties of EPS concrete can not be reflected objectively and realistically.However,the numerical simulation method can not only obtain its performance indexes,but also observe the process of damage and fracture.Therefore,numerical simulation has become an important means to study EPS concrete.In this paper,starting from the micro level,in order to focus on the analysis of effect of EPS particles on the mechanical properties of concrete,EPS concrete is considered as a two-phase composite material consisting of EPS particles and matrix of concrete.Adopting the aggregate gradation theory and random distribution theory,a random aggregate model of concrete EPS based on Monte Carlo method is established.Using the MATLAB software to establish the concrete models of four kinds of circular EPS particles with the area share of 10%,20%,30%,40% and four kinds of polygonal EPS particles with the area share of 10%,20%,30%,40%.Using APDL language to lead them in the ANSYS,given its corresponding mechanical parameters to simulate the EPS concrete damage process under static load.In order to make the model real and effective,the damage of concrete matrix is studied firstly,and the stress-strain curve is obtained,which is compared with the real stress-strain curve.It is found that the stress-strain curve is consistent with the real stress-strain curve.It is proved that this method is feasible.And then the effect of EPS particle area occupancy,arrangement distribution and particle shape on the mechanical properties of EPS concrete is studied.The results show that the failure of concrete is mainly brittle failure when the occupation of EPS particle area is small.With the increasing of EPS particle area occupation,the brittle failure gradually changes to ductile failure.And when the EPS particle area occupancy is low,the effect of random distribution and regular distribution on EPS concrete is small.With the increasing of EPS particle area occupation,the regular distribution shows large residual stress relative to randomdistribution.And when the area occupancy of EPS particle is the same,compared with the random distribution,the regular distribution has a smaller brittleness index,and shows good ductility.When the shape of the particle is triangular,the maximum ductility of the stress is the best.When it is a square,the stress is minimum but the ductility is the best.The stress-strain curve of concrete is similar to the brittle index when the shape of EPS particles is circular and pentagonal.