Study On Impact Performance Of PE-ECC Beam Based On Numerical Analysis

In recent years,with the development of economy and society,people’s demand for buildings has gradually changed to enhance their appearance,environmental protection and comfort requirements.Therefore,new building materials and their material properties have attracted the attention of scholars.New building materials can be prepared by adding a certain amount of fiber to cement-based materials.Polyethylene fiber(PE for short),as one of the fibers,can improve the performance of concrete to a certain extent,especially its tensile toughness.Engineered cementitious composite(ECC)is Engineered with desert sand to enable strain hardening and multiple crack as well as localization of the formulated material.Secondly,during the use of building materials,in addition to the static load,but also bear dynamic load,such as vehicle load,impact load.When the structure is subjected to a large impact,it will cause a certain degree of destruction and damage to the building.Therefore,it is very necessary to study the constitutive relationship and dynamic properties of PE-ECC materials.In this paper,on the basis of a certain amount of desert sand,using the water-binder ratio and the volume content of PE fiber as the main variables,the tensile and compressive tests of PE-ECC were carried out.According to the experimental results,the tensile and compressive constitutive model of PE-ECC is given,and the finite element analysis model of PE-ECC beam is established on this basis.The impact resistance of PE-ECC is discussed and analyzed by numerical simulation.The main research contents and conclusions are as follows:(1)Uniaxial compression and tensile tests were carried out on PE-ECC prisms and dumbbell specimens with desert sand substitution rate of 20%.Through the analysis of the variation rule of various compression and tensile indexes under different factors(fiber volume content,water-binder ratio),it is concluded that when the fiber volume content is 1.5%and the water-binder ratio is 0.25,the performance of PE-ECC is better.A uniaxial compression and tension constitutive model of PE-ECC was proposed based on the analysis of the stress and strain relationship of PE-ECC according to the curves obtained from the tests.(2)The finite element model of PE-ECC beam bending test was established by using the finite element software ABAQUS and using the above PE-ECC constitutive model.By comparing and analyzing the results of numerical simulation and test,including failure mode and load-displacement curve,the two are in good agreement,which verifies the accuracy of the constitutive model.(3)Based on the above analysis,the finite element model of reinforced concrete beam under impact load is established,and the analysis step length,boundary conditions and loading mode required under dynamic load are determined by comparing with the experimental results in the literature.Through the analysis of parameters such as different fiber volume content,different impact velocity,impact mass and so on,the change rule of impact property of PE-ECC beam under the action of various factors is obtained,and the orthogonal analysis shows that the impact velocity has the greatest influence on the peak value of impact force,and the impact mass has the greatest influence on the mid-span displacement.