| The thin-wall part has been widely applied in many advanced manufacturing technology fields,involving aeronautics and astronautics,marine equipment and radar antenna,etc.However,in the assembly process,the assembly deformation error and control,namely,the advantage and disadvantage of assembly accuracy are a key problem that it is whether meeting the demands of the design performances for products.In this paper,the antenna as a research object consists of a large amount of metal thin-wall parts through some joining-assembly methods.Due to the physical properties of thin-wall part with lower rigidity,the induced deformation error,even assembly error in the assembly or manufacturing process are easily generated to cause the lower assembly quality and property.Therefore,the joining-assembly characteristics and deformation mechanism under the condition of a certain assembly relationship are theoretically researched and effectively explored is extremely essential for antenna thin-wall part,which will provide a reliable theory analysis foundation for improving assembly quality and assembly efficiency.In view of the requirements of deformation error and control for antenna thin-walled components,the assembly unit of thin-wall part for whole antenna assembly structure is taking as the research object,focusing on the relative problems of joining-assembly for thin-wall parts,combining with several optimization algorithms,finite element method,the constructed methods of processing experiment data and others modeling methods,based on the assembly technique of antenna thin-wall part,the study on experiment and various characteristics analysis is carried out in this thesis.Firstly,in view of the fixturing layout problem in the process of thin-wall part assembly and the deformation error or assembly accuracy problem which is caused by different clamping positions and clamping forces,considering itself gravity of thin-wall part,the clamping positions for thin-wall part are optimized by several optimization algorithms involving adaptive simulated annealing algorithm,multi-island genetic algorithm and particle swarm optimization algorithm,and then the several optimization results are compared and analyzed to exhibit the optimization performance of an algorithm.In addition,considering the contact between the thin-wall part and fixture in the process of its fixturing and clamping,the contact deformation model is built to explore the relationship between the deformation and contact force.According to above analysis,some relative measurements and principles of thin-wall part assembly are also taken and presented to improve the assembly quality and accuracy for antenna thin-wall part.Secondly,in the thin-wall part assembly process,whether it is clamping position layout problem or the contact deformation problem,they are induced by the joining-assembly of thin-wall parts.As for the joining assembly way for thin-wall part,the riveting assembly way is firstly taken to connect thin-wall parts and other components.However,in view of the riveting assembly deformation problems,the riveting assembly deformation model is established,and then the static and transit simulation results for riveting assembly are analyzed by finite element simulation method,and the effect of different number of rivet for riveting assembly parts on riveting deformation is also researched.After that,the measuring points experiment on the thin-wall parts for riveting assembly structure is carried out to prove that the established model is effective,and then the processing method of experiment data is presented to finish experiment studies and explore the riveting assembly rules and mechanisms of thin-wall part.Furthermore,from the perspective of micro deformation,the micro deformation model is proposed to reveal the similarity property that the micro deformation reflects the variation tendency of macro deformation for thin-wall part.And then,the relative problems in the assembly process through welding assembly way are also effectively explored and analyzed.Firstly,in the welding assembly process,in view of thermal characteristic problems for vary kinds of welding assembly structure units,the multi-size finite element model of welding assembly structure for thin-wall parts is established,considering the different conditions on welding assembly characteristics,and adjusting the relative parameters and other variables to control temperature field distribution of welding assembly,the variation relationships between temperature,residual stress and deformation for thin-wall parts of I-shape and parallel T-shape welding assembly are explored,which will provide an analysis foundation for further studying on parameters optimization of welding assembly process.What is more,as for the effect of different variable factors on welding assembly characteristics of thin-wall part,the measuring points experiment of T-shape thin-wall part welding assembly is carried out,and combining with micro deformation model of riveting assembly,the welding assembly deformation results are compared and analyzed.Hereby,the applicability and effectiveness of welding assembly is also further analyzed and explored.Finally,for several relative complex welding assembly structure types involving abovementioned riveting assembly structure,combining with the contact relationships for thin-wall assembly,considering different thicknesses of thin-wall part,different welding assembly directions and welding assembly sequence,and other variable factors,etc.,the measuring points experiments for these relative complex welding assembly structure are carried out to analyze thin-wall part deformation.Hereby,the fractal dimensional values for different thin-wall part are calculated and determined.Moreover,the unified index method equation is constructed to calculate final micro deformation value.Meanwhile,from the perspective of micro and macro,the assembly deformation problems for thin-wall part are analyzed to explore the micro deformation mechanism and reveal the similarity rule between micro deformation and macro deformation.Therefore,according to the thin-wall part assembly for different assembly structure types and different joining-assembly ways,the obtained micro and macro deformation results with micro theory model and thin-wall part assembly experiments are compared and analyzed,and the applicability,effectiveness and generality for the established micro theory model which are fractal theory model and its correction model are also well further verified. |
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