Modeling And Analysis Of Assembly Deviation Transmission For Aerospace Power Pipeline

Power piping system is the main structure of gas,liquid,and other power medium transportation in major equipment such as rockets,airplanes,and ships,it has an important impact on the operational performance,service life,and reliability of the entire equipment.The power piping system of aerospace equipment has a complex structure and many types.Its manufacturing mode is mainly based on single or small batch manufacturing.There are various deviations in the processing and assembly processes of piping parts,which leads to the extreme deviation of the end position of the piping.As a result,the accuracy of the closing end of the pipeline is low,and the success rate of a single assembly is low.It needs to be reworked for multiple times,or even remanufactured and assembled,which affects the production cycle of the entire pipeline system.Therefore,how to determine the characteristics of the deviation of each component of the piping system and reveal the influence of each deviation on the final deviation of the pipeline is the main challenge to improve the manufacturing accuracy of the power pipeline system.Aiming at the problem of difficult to control assembly deviation in the manufacture of aerospace power pipelines,this dissertation studies the measurement extraction and deviation characterization of different deviations in the processing and assembly of pipeline parts,constructs a pipeline assembly deviation transfer model,and the transmission characteristics and influence rules of each deviation are analyzed,and conducts experiments and simulation analysis of aerospace power pipeline assembly.Finally,the paper has verified the pipeline assembly deviation transmission model proposed in this dissertation,revealed the influence mechanism of different deviations on the pipeline end-position attitude,and provides method support for the design and optimization of aerospace power pipeline system assembly process.The main research contents of this dissertation are as follows:(1)A method for measuring,extracting and characterizing the deviations of pipe forming and welding deformation during pipe assembly is established.The specific characteristics of forming deviations and welding deformation deviations in pipeline assembly are analyzed through experiments and simulations.Based on this,a form of torsor characterization for forming deviations and welding deformation deviations of pipe parts is proposed.(2)The deviations propagation model of pipelines is established based on the exponential product formula.Based on the analysis of the pipeline assembly deviation transfer process,the end position pose deviation of the pipeline and the variation of the torsor are introduced,the assembly deviation propagation model is improved.Three indexes—absolute pose deviation,the characteristic control point translation deviation,and the characteristic control vector rotation deviation—are defined to evaluate effectiveness of the assembly deviation transfer model.(3)A method of pipeline deviation simulation analysis based on Monte Carlo simulation method is proposed.The analysis process of pipeline deviation analysis are determined,the random sampling method of dimensional deviation based on the low deviation sequence is improved and the random generation method of deviations in pipeline assembly is further proposed;The analysis indexes such as the absolute spatial pose deviation,the average of the characteristic control point translation deviation,and the average of characteristic control vector rotation deviation are defined.By clearly defining the conditions of the pipeline closing with little stress,calculation method of pipeline assembly success rate is given.(4)An assembly experiment and simulation analysis of aerospace power pipeline prototypes are conducted.Combining the point cloud data of the experimental prototype with the ideal model of the product,the torsor form representation of the assembly deviation of the prototype was obtained,and the assembly deviation transfer model of this case was established.The deviation transfer model of pipeline sample assembly is established.The analysis and calculation and experimental results verified the validity of the deviation transfer model.A simulation analysis of pipeline assembly deviation based on Monte Carlo simulation is carried out,and the mechanism of the influence of different deviation on the end position and posture of the pipeline is revealed,which provided support for the design and optimization of pipeline assembly process.