| In this thesis,the key components of a large caliber artillery ammunition automatic loading system,the coordinated shell conveyor with double trunnion arrangement and the coordinated charge conveyor with single trunnion arrangement,were taken as the research object.Combined with the theories and methods of multi-body dynamics and modern structural optimization design,the structural optimization design of the main load-bearing component coordination arm is carried out.The main research contents are as follows:(1)Firstly,the structural form and working principle of the single/double layout trunnion coordinators were introduced respectively.Based on the experimental data and PID control co-simulation,the rigid-flexible coupling dynamics models of the coordinated charge conveyor and the coordinated shell conveyor were established respectively,and the coordination process under different firing angles was simulated and verified.The dynamic stress response and the ultimate load of the arm in the coordination process are obtained as the boundary conditions of the subsequent optimization analysis.(2)The finite element model of the shell/charge coordination arm was established to analyze its static and dynamic characteristics,and the stress results were compared with the rigid-flexible coupling model to ensure the correctness of the boundary conditions of the finite element model and the credibility of the analysis results.Based on the results of finite element analysis,the corresponding optimization schemes were developed for the different structural forms and performance of the two coordination arms.(3)The material substitution based on the equal stiffness of double trunnion layout shell coordination arm based on parametric optimization was carried out.The parametric finite element model of the elastic coordination arm and the optimization script under limit conditions were established.The material thickness range was selected through the approximate formula of equal stiffness substitution.Taking the key shape scale parameters and material thickness parameters of the structure as the design variables,the approximate model about the mass response of the arm was constructed through the sample points collected in the optimal Latin hypercube design.The optimal parameter combination was obtained by using MIGA.Finally,under the condition of meeting the working requirements such as structural stiffness and strength,the weight of the arm was reduced by 25.1%.(4)To improve the material utilization and realize the optimization of the charge coordination arm,taking the compliance and low-order eigen frequencies as the static and dynamic optimization objectives respectively,the compromise programming method was adopted to define the sub objectives of multi-objective and multi-stiffness optimizations,and the mean frequency formula was employed to define the sub objective of dynamic optimization.The static and dynamic multi-objective topology optimization model of the coordination arm structure was established.According to the optimization results,the structure was improved,designed and verified.Finally,on the basis of reducing the mass by 10.2%,the coordination arm structure with improved overall stiffness,strength and low-order natural frequency was obtained.Under the condition of meeting the structural working requirements,the material utilization is improved and the effect of lightweight is achieved.Through the structural optimization design of the two types of coordination arm,the weight of the coordination system and the moment of inertia in coordination work can be reduced under the condition of meeting the structural stiffness,strength and working requirements.It provides ideas for the structural optimization design of other components in the loading system,so as to realize the optimal matching between weight and performance of the loading system. |
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