Research On Heat Transfer Characteristics And Thermo-Mechanical Coupling Performance Of Lattice Structural Plate

Lattice structural plate is a new type of light-weight and high-strength structural plate.When the structure has heat insulation/heat dissipation requirements,it can be designed to achieve the purpose of heat insulation or heat dissipation of the structure.The key is whether the heat transfer capability of the structure can meet the needs of the existing heat load,and then whether the structure needs to be insulated/heat dissipation design.Therefore,it is necessary to evaluate the heat transfer capability of the structure.The existence of thermal load will affect the bearing capacity of the structure,that is to say,the thermo-mechanical coupling performance of the structure needs to be analyzed.The direct way to adjust the thermo-mechanical coupling performance of the structure is to change the structural parameters,which will inevitably lead to changes in the weight of the structure.In this paper,the following work is done for the heat transfer performance,thermo-mechanical coupling performance of lattice plate and how to design parameters to ensure that the structure achieves the purpose of light weight,bearing thermal and mechanical loads.(1)The heat transfer capability of the structure was evaluated.The heat transfer form of structure is analogous to one-dimensional heat conduction of three-layer flat wall,and the equivalent thermal conductivity coefficient is used as a parameter to measure the heat transfer capacity of structure.For the middle layer,there are metal rod heat conduction,internal space radiation heat transfer,natural convection heat transfer between air and internal surface.Because the value of internal natural convection heat transfer is very low,the influence of internal natural convection heat transfer is neglected.Therefore,the heat conduction and radiation heat transfer of rods can be assumed to be "parallel" relationship.Based on this,the equivalent thermal conductivity of lattice plate was deduced.Then,the equivalent thermal conductivity of the structure with representative design parameters was calculated by numerical simulation,and the results were compared with those of the formula.(2)The thermo-mechanical coupling performance of the structure was studied.In order to comprehensively analyze the influence of design parameters on thermo-mechanical coupling performance and reduce the amount of calculation,the orthogonal design method was used to select the calculation model.In ABAQUS,sequential thermo-mechanical coupling was used to calculate the thermo-mechanical coupling performance of the structure under different design parameters,heat flux density and pressure loads,and the equivalent stress field was analyzed.(3)Structural performance prediction and optimization design were carried out.The thermo-mechanical coupling calculation data were sorted out,and the relationship between input variables(design parameters,boundary conditions)and output variables(maximum equivalent stress value)was established by using BP neural network.Based on the relationship established,the constraints were determined.With the relative density of the structure and the temperature difference between the upper and lower surfaces as the objective,the design parameters under the given load were determined by genetic algorithm,so that the structure achieved the purpose of light weight and heat-carrying capacity.Finally,the optimization results were verified by simulation.