Effect Of Thermal Transfer Performance On Wall Of Horizontal Warehouse For Grain Load Damage

China is the country with the largest amount of grain in storage and the longest reserve in the world.China’s national conditions dictate that it must build its own food security reserve system.However,due to technical and economic constraints during the Ninth FiveYear Plan and Tenth Five-Year Plan periods,80% of the warehouses built were bulk grain horizontal warehouses.In service,the wall structure of both horizontal warehouses has been damaged under the repeated action of long-term grain loads,and the damage to the wall structure has led to changes in the warehouse structure.In service,the wall structure of both cottage warehouses has been damaged under the repeated action of long-term grain loads,and the damage to the wall structure has led to changes in the heat transfer performance of the walls,which has reduced the thermal insulation performance of the cottage warehouses and caused changes in the temperature and humidity of the grain,with important effects on the storage safety of the grain.For this reason,the study of wall damage on wall heat transfer is important for the later maintenance and reinforcement of walls.In this paper,a brick wall lateral pressure test and a wall heat transfer performance test were designed,based on the test results to obtain the wall damage parameters,and the effect of wall damage on its heat transfer performance under different loading levels and different cycle times,based on which the relationship between the wall damage factor and the heat transfer coefficient was established in combination with the composite material homogenization theory.The specific work and main conclusions of this paper are as follows:(1)The design of the wall lateral pressure test device,static loading test under wall lateral pressure,through the wall deformation monitoring,study the brick wall at different loading levels and different cycle times under the cumulative damage produced by the wall,to reveal the deformation characteristics of the wall plate.The research shows that as the loading level increases and the number of cycles increases the displacement of the wall increases,the deflection of the wall varies at different displacement measurement points and the residual displacement of the wall varies less.Under the same loading level,the hysteresis curve of the wall differs at different displacement measurement points,but the force performance of the wall is basically the same,the trend of the wall hysteresis curve is basically the same,and the overall performance of the vertical displacement of the wall is obtained through the test,the load-displacement curve hysteresis loop is relatively sharp and thin,almost close to a straight line,and the residual deformation is small.(2)Through the loading test of the wall and the thermal performance test of the wall after damage,the thermal performance parameters of the wall after damage were obtained at different loading levels and the same number of cycles,and the results of the study showed that: the parameters of the wall will stabilize at about 1500 min,and the thermal performance parameters of the wall when the wall was not loaded and the wall after damage were compared,and it was obtained that with the increase of the loading level,the heat transfer coefficient of the wall increased.The heat transfer coefficient of the wall increases;different displacement measurement points,the heat transfer coefficient of the wall changes differently,and it is found that the heat transfer coefficient of the wall increases by 32.00%compared to the initial heat transfer coefficient of the wall at the displacement measurement points where the displacement changes more.(3)Based on the damage evaluation index of brick wall,the test data of wall damage coefficient under different loading levels and different cycle times were obtained,and the relationship between loading level and damage coefficient under different displacement measurement points and different cycle times was established by using the Weibull probability density distribution function,and the values of b and m were obtained by fitting regression,and it was found that the correlation coefficient between loading level and damage coefficient was high,indicating that the relationship between loading level and damage coefficient obeyed the Weibull distribution;Then,the wall damage coefficient under different cycles at different loading levels is studied,and the wall damage coefficient has a linear relationship with the number of load cycles.At the same time,a mathematical model between the load factor and the damage coefficient is established,and the accuracy of the calculation model is verified.(4)Through the thermal performance test results,the heat transfer coefficient of the wall without damage and the heat transfer coefficient after loading cycles were obtained by using the thermal performance calculation principle,and the mathematical model of the heat transfer coefficient and damage coefficient of the wall was established based on the series model and parallel model obtained from the homogenization theory of composite materials.The heat transfer coefficients of the span of the wall after six cycles of loading at different loading levels are combined to obtain the calculated values of the damage coefficients associated with the heat transfer coefficients,and the calculated damage coefficients are compared with those influenced by the loading levels and the number of cycles to verify that the heat transfer coefficients are influenced by the number of cycles and the loading levels.