Self-Sensing Electrical And Mechanical Properties Of Cement-Based Composite Materials And Its Application In Bridge Health Monitoring

Graphene has local super strong electrical conductivity,high electron mobility and thermal conductivity,good mechanical properties and good stability.It is an excellent filling material for self-sensing cement-based composite materials.The development of self-sensing cement-based composite materials provides a broad application prospect.In this paper,based on ANSYS software,the electrical and mechanical properties of self-sensing cement-based composites are studied.The main research contents are as follows:(1)Adopt APDL in ANSYS to establish a three-dimensional self-sensing cement-based composite material random distribution model,and simulate the current vector density of graphene-modified cement-based composite material models with different aspect ratios and different volume fraction ratios under voltage And effective resistivity distribution.The results show that: under the same voltage loading,the conductivity of the composite material increases with the increase of the graphene content;under the same graphene volume content,the smaller the aspect ratio of the graphene,the conductivity of the composite material The better;the effective resistivity of the composite material decreases with increasing graphene content;under the same graphene volume content,the smaller the aspect ratio of graphene,the smaller the effective resistivity of the composite material.(2)A composite model of graphene with a volume fraction of 0.04% and 0.05% was established using ANSYS,and the von Mises stress and the first principal stress cloud distribution of these two models under tensile load were simulated.The simulation results show that: under the effect of tensile deformation,the composite material with graphene content of 0.04% has a uniform von Mises stress distribution and small stress,and the two ends of the reinforcement first reach yield failure.The first principal stress distribution is also relatively uniform and the stress is relatively small,and cracks are generated first at both ends of the reinforcement.The composite material with 0.05% graphene content has a larger von Mises stress value,the first principal stress distribution is uniform and the value is smaller,and cracks are generated on both sides of the reinforcement first.(3)A composite material model with graphene content of 0.04% and 0.05% was established,and the von Mises stress and the first principal stress cloud of these two models under the compressive load were simulated.The simulation results show that: under the action of compression deformation,the composite material with graphene content of 0.04%,the von Mises stress distribution is relatively uniform and the stress is large,and the two ends of the reinforcement first reach yield failure.The first principal stress distribution is also relatively uniform and the stress is relatively large,and cracks are generated first at both ends of the reinforcement.The von Mises stress and the first principal stress of the composite material with graphene content of 0.05% are similar to those of the composite material model with graphene content of 0.04%.(4)Through the finite element simulation of the position of the bridge where the stress is large under the self-weight load,to find the placement of the sensor,and design a simple health monitoring system.