Study On Mechanical Performance Of Aluminum Alloy Solar Support System Placed On Single-layer Metal Roofing

Distributed photovoltaic power generation systems use buildings as carriers.In order to improve the utilization efficiency of solar energy,they are generally installed on buildings with large body surface area and have a certain installation inclination angle.The installation angle increased the wind receiving area of the photovoltaic panel,so the wind load had an important influence on the load carrying capacity of the photovoltaic system.The magnitude of the wind load was related to the wind direction angle and the installation position of the photovoltaic panel,and the current load code in China did not provide the calculation formula for the wind load of the photovoltaic system.Therefore,it is necessary to carry out the study on mechanical performance of aluminum alloy solar support system placed on single-layer metal roofing.In this paper,the numerical wind tunnel technology was used to calculate the wind pressure of the solar aluminum alloy bracket roof,and the bearing capacity of the bracket under wind load,snow load and self-weight was analyzed.The main research contents of this paper were as follows:1.Through the tensile test of aluminum alloy profiles,the stress-strain data of 6063-T5 profiles were obtained,and the results were compared with the commonly used aluminum alloy material formulas.The results showed that the experimental data of the elastic phase was in good agreement with the formula,the data of the plastic stage was higher than the formula calculation result.The data obtained from the tensile test provided the necessary material parameters for finite element simulation.2.By studying the numerical wind tunnel theory,the boundary conditions at the entrance of the simulated wind field,the turbulence model and the treatment methods for the near wall were determined.3.The three-dimensional models,grid processing and wind field simulation were carried out by SOLIDWORKS,ICEM and FLUENT software.By comparing the numerical wind tunnel simulation results with the wind tunnel test results,in order to determine the correctness of the proposed turbulence model and parameter settings.The SST k-? turbulence model was used to calculate the wind pressure coefficient and wind pressure distribution on the PV panel with the inclination angle of 10°,and the force in the six directions of the X-axis,Y-axis and Z-axis.The simulation used two variables for analysis,including the wind direction angle(0° and 180°)and the installation position of the photovoltaic array on the roof of the building.The photovoltaic panel was mainly subjected to lift.When the wind direction angle was 0° and the photovoltaic system was in the middle of the roof,the Y-axis direction was mainly affected by the pressure.4.The three-dimensional models of photovoltaic modules and brackets,profiled steel plates and joints were established by the finite element software ABAQUS.The stress,strain change and ultimate bearing capacity of each model were analyzed by applying loads,and the influence of the installation position of photovoltaic panels on the bearing capacity of profiled steel sheets was analyzed.The ultimate bearing capacity of the aluminum alloy support on the roof of the profiled steel plate was obtained.The load carrying capacity from weak to strong is followed by profiled steel plates,photovoltaic modules and brackets,and joints.Combined with the numerical simulation results of the wind tunnel and the load combination values calculated by the load code in China,the pressure and lift applied to the photovoltaic panel in the actual environment were obtained by the most unfavorable principle,and the results were compared with the ultimate bearing capacity of the model.The results showed that if the photovoltaic panel was installed on the roof of the profiled steel plate,it was necessary to strengthen the roof or increase the number of aluminum alloy supports;if the photovoltaic panel was installed on the concrete roof or the ground,the optimized design of the weak part of the aluminum alloy support was required.