Experiment And Numerical Simulation On The Mechanical Properties Of Concrete Plates Under Sodium Fire

Study the damage characteristics,heated and forced conditions of concrete structures under the effect of sodium fire,it is of great significance to the sodium fire prevention design of the fast reactor nuclear island plant.This paper is based on the actual engineering background,we have made four concrete plates of different thicknesses,and fully consider the effect of heat conduction of steel plate on the edge of specimens,the spray sodium fire experiment and numerical simulation analysis were carried out for the concrete specimens.The main contents of this paper as follows:(1)Using the experimental platform of spray sodium fire,we performed sodium fire experiments on concrete specimens of four thicknesses,and measured the temperature and strain data of each specimen.Experimental results show that the surface of specimens can reach 300~800?,and the surface concrete has been severely spalling;except for the serious areas of surface collapse,the temperature of specimens' upper test points were cut off at about 100?,and the temperature rise of the lower test points were below 10?.Therefore,in spray sodium fire conditions of short time,100 mm thick concrete plate can effectively cut off the heat of fire,and the back surface of 300 mm thick specimen is hardly affected by sodium fire.This provides reference for the design of sodium fire protection in the actual nuclear island plant.(2)Using ABAQUS software to model the sodium fire experiment,we apply the measured temperature on the surface of models,and analyze the change law of concrete specimens' temperature and stress.The results of numerical simulation show that the maximum temperature of the lower measuring points of each specimen model is less than 70?,and the maximum Mises stress on the back surface is below 11MPa;the lower measuring points' temperature rise of 300 mm thick specimen is less than 4?,and the largest Mises stress on the back surface is only 2.67 MPa.From the numerical simulation results,we know that 300 mm thick concrete specimen can provide good insulation for temperature and thermal stress.(3)We compared the spray sodium fire experiment with the numerical simulation results,and analyze the temperature and stress deviations of two methods.The contrast results show that the temperature results of concrete specimens' lower measuring points are in good agreement,ABAQUS software is highly feasibility and accuracy for temperature field analysis of the spray sodium fire;the strain data measured by experiment was strongly disturbed,it led to a large deviation of Mises stress on the back surface of specimens,so the ABAQUS software can be used to correct and predict the stress results of sodium fire experiments.This provides a new method for the analysis of concrete structures' heat and stress under the action of spray sodium fire.