Fuzzy Comprehensive Evaluation Of The Launch Pad's Reliability Based On AHP

In recent years,with the gradual maturity and steady development of China's space industry,there are more and more space launch tasks.With the success of manned space flight and the development of space flight program,in particular,it is more necessary to implement each launch mission on the premise of low risk and high reliability.In order to ensure stable and continuous operations of launch pads,ensure availability of launch pads under high-density space launch tasks,ensure that mission schedules do not delayed due to failure of launch pads,and that security issues do not occurred due to failure of launch pads,this paper proposes a launch platform reliability evaluation program based on the engineering application underground that uses a combination of analytic hierarchy process and fuzzy comprehensive evaluation method.This program can improve the accuracy of reliability evaluation of launch pads and ensure the smooth process of space launch test.Meanwhile,it can obtain greater economic and social benefits.First,the paper uses fiber Bragg grating inspection technology to test the stress and temperature changes of a launch pad under two operating conditions during the launch mission.By comparing and analyzing the measured data,it is known that the measuring points' stress values of the fiber Bragg grating sensors under both operating conditions are lower than the allowable stress of the materials,and the ambient temperature values are lower than the environmental requirements of the sensors.It can provides an important support for the indices analysis of the structural strength reliability of the launch pad.Secondly,based on the selection principle and method of reliability indices,this paper selects the launch pad reliability indices,and has deep discussion and analysis on the specific meanings and evaluation methods of each indices,including structural reliability assessment index: stress,vibration,deformation,cracks,coating ablation and material parameters;and mechanism reliability assessment index: transmission resistance and braking reliability.Also,due to the specialty and comprehensiveness of the core index-structural stress in engineering practice,the paper uses the system reliability calculation formula and the stress-strength interference theory to process the measured stress at each location comprehensively.Thus,the core index-structural stress is converted to the structural strength reliability of the launch pad.Thirdly,combining the expert's technical experience and the hierarchical structure model of the launch pad,this paper obtains the reliability evaluation system of the launch pad that makes the numerous and cumbersome evaluation indices organized,layered and quantized.Meanwhile,in order to provide more reasonable evaluation for the launch pad's overall reliability,the paper proposes a reliability fuzzy comprehensive evaluation method for the launch pad based on the analytic hierarchy process,and establish a mathematical model of multistage fuzzy evaluation of reliability evaluation.The model handles the uncertainties and ambiguities in reliability evaluation and thus makes the launch pad reliability evaluation results more accurate and reliable.Finally,the paper uses C# programming software design and develop an evaluation software for the launch pad reliability based on the established reliability evaluation mathematical model.This software uses status indicators of the launch pad as input conditions and outputs the launch pad's inherent reliability and evaluation results of launch mission.The aerospace experts can make decisions on whether to launch or not after reviewing the results.At the same time,this software develops the indices set's intelligent matching function and the user-defined of judgment matrix,and also can view the historical data curves under different conditions,which makes it more convenient for the aerospace technicians to perform the reliability analysis of the launch pad and is more targeted,memorable,and flexible than the general analytic software.