基于FMECA的某自动步枪发射机构可靠性分析

目的 分析某自动步枪发射机构的可靠性。方法 用故障模式、影响及危害性分析(FMECA)的方法对自动武器发射机构进行危害度分析，通过参考GJB 450A和GJB 1391制定危害程度的评判参考标准，列举出故障，并对故障的危害程度进行评分，找出危害影响最严重的故障优先进行可靠性分析。再通过三维建模软件和动力学分析软件对发射机构进行动力学仿真，将动力学仿真得到的结果导入有限元仿真软件，通过力学分析得到零部件的最大应力，运用应力–强度干涉理论求出可靠度。最后给出严重故障的可靠度分析。结果 在FMECA分析综合评分后，得出某自动步枪发射机构最严重的故障模式是超越保险异常击发。通过ADAMS仿真进行受力分析，发射机构中受力最大的零件为单发阻铁和击锤，使用应力–强度干涉理论进行可靠度计算，计算得到单发阻铁的基础可靠性为99.952%，击锤的基础可靠性为99.955%，发射机构的基础可靠度为99.907%。结论 发射机构的基础可靠度非常高，因此影响发射机构可靠度的因素主要是机构运动不可靠。在自动武器非正常操作时，将导致零部件位置异常，从而出现任务不可靠。可以通过改进零部件的方法防止故障发生，提高发射机构的任务可靠度。

Reliability Analysis of an Automatic Rifle Firing-mechanism Based on FMECA

This paper aims to analyze the reliability of an automatic rifle firing-mechanism. The fault mode, impact and hazard analysis (FMECA) was used to analyze the hazard degree of automatic weapon launching mechanism. By referring to GJB-450a and GJB1391, a reference standard for evaluating the degree of damage was formulated and the fault was listed, as well as the degree of damage of the fault was scored, thereby identifing the fault with the most serious impact and conducting reliability analysis with it preferentially. Then, the dynamic simulation of the launching mechanism was carried out by using 3D modeling software and dynamics analysis software, and the results of dynamics simulation were imported into the finite element simulation software. The maximum stress of the parts was obtained by mechanical analysis, and the reliability was calculated by using stress-intensity interference theory. Finally, the reliability analysis of serious faults is given. After FMECA analyzed the comprehensive score, it was concluded that the most serious failure mode of an automatic rifle firing-mechanism was the exceedance insurance abnormal firing. ADAMS simulation was used to conduct stress analysis, and the biggest stress parts in the launching mechanism were semi-automatic sear and hammer. The stress-intensity interference theory was used to calculate the reliability, and the basic reliability of semi-automatic sear was 99.952%, the basic reliability of hammer was 99.955%, and the basic reliability of the launching mechanism was 99.907%. The foundation reliability of launching mechanism is very high, so the main factor affecting the reliability of launching mechanism is the unreliability of mechanism motion. The abnormal operation of automatic weapons will lead to the abnormal position of parts, resulting in unreliable tasks. The failure can be prevented by improving parts and components to enhance the mission reliability of launch mechanism.