Dynamic Optimization Method Of Thermal-mechanical Coupling Structures Based On ESLM

Traditional static optimization technology has been difficult to meet the actual requirements of engineering structures for dynamic performance,dynamic optimization technology has a huge potential application value in the field of complex machinery and equipment.However,time-dependent dynamic constraint handling difficult and timeconsuming iterative computation problem has restricted the dynamic response optimization technology in the practical application of engineering machinery,especially in the engine load under coupling field of machinery and equipment,dynamic response optimization design has not yet formed a complete research system,efficient and practical in theory.ESLM(Equivalent Static Load Method)proposed for the dynamic response of the optimization technology provides effective solutions,and under a single mechanical Load of the truss,beam,rod,sheet or discrete nodes such as simple structure,grid,require less lower structure optimization design has been widely applied,yet for heat engine under the coupled action of Load less complicated engineering machinery research,thus carry out the thermal-mechanical coupling structure dynamic optimization Method based on ESLM research has a certain engineering significance and theoretical value.(1)Based on the analysis of the principle of equivalent static load method of displacement,this paper takes the connecting rod of an internal combustion engine as the research object,transforms the problem of dynamic response optimization of the connecting rod into the static optimization design under multiple equivalent static loads based on displacement response,and realizes the dynamic response optimization design of the connecting rod.Furthermore,the dynamic optimization based on ESLM is compared with the traditional static optimization and direct dynamic optimization methods under extreme conditions.The research results show that:Compared to the dynamic optimization design,without considering the influence of the structural mass and inertia,traditional extreme conditions of static optimization design optimization accuracy is lower,compared with the static optimization method,two kinds of dynamic optimization of connecting rod quality than its decreased by 3.1%,and two methods of dynamic optimization under the stress and deformation of connecting rod results are basically identical,but compared with the traditional direct dynamic optimization method,based on the dynamic response of equivalent static load method to optimize the iterative calculation is 185 times more direct dynamic optimization efficiency,optimize efficiency improved significantly.(2)To explore the dynamic optimization method based on equivalent static load method in hot-structure coupling field of application,the paper combines thermal elasticity theory and method of equivalent static theory,first of all from the Angle of the theory of heat load and mechanical load was deduced under the coupled action of dynamic load equivalent static transformation mechanism,and is verified with cantilever beam as an example,by comparing before and after the equivalent node displacement values,equivalent theory is verified in the physical field,hot-structure coupling physical field also apply,for the thermal-mechanical coupling structure dynamic optimization design based on ESLM laid a theoretical foundation.(3)The paper in a typical transient thermal-mechanical coupling structure--piston diesel engine as the research object,through the piston engine coupled transient dynamics analysis,extract the stress and displacement of the 16 key location point as a result,the calculation of the equivalent transformation compared with dynamic loading result analysis shows that the maximum equivalent stress of equivalent inspection area before and after the transformation error is within 3%,the maximal displacement error within 2%,and equivalent transformation result credible;Further analysis comparing the piston engine load under the action of static optimization and dynamic optimization based on ESLM,the results show that the two optimized piston deformation,stress and the temperature of the first ring groove similar results,but the quality based on dynamic optimization than static optimization ESLM piston was reduced by4.7%,the results fully proved the superiority of dynamic optimization method based on ESLM.Through the equivalent static method in the application of optimizing design of connecting rod,piston,confirmed the method of equivalent static load on structure of hot-coupled physics field is equally applicable,this paper studies the application of equivalent static load method has certain extension,as well as the mechanical structure under the effect of heat-structure coupling physical field of the mechanical structure dynamic optimization design provide certain help.