基于蒙特卡罗法的高速钢丝锥可靠性分析

高速钢丝锥主要失效原因之一是由断裂、崩刃所引起的破损失效,确定丝锥的可靠度对于自动化、高精密加工具有十分重要的意义。通过顺序统计量理论考虑丝锥受到冲击载荷的次数,并利用应力—强度干涉模型,以多次加工后切削刃上的最大扭转应力超过丝锥材料临界疲劳应力为失效判据建立高速钢丝锥的可靠度模型,并通过少量试验,结合蒙特卡洛法随机生成加工时分布在丝锥切削刃上的应力和丝锥材料临界疲劳应力,将得到的样本值进行比较,得出高速钢丝锥的可靠度。最终,通过恒应力加速试验对蒙特卡洛模拟法的计算结果进行了验证。

Research on Reliability of High Speed Steel Tap by Monte Carlo Simulation

Tool reliability is very important for automatic machining system.The primary failure mode for high speed steel tap is fatigue wear.A reliability model is developed for failure-dependence systems under repeated loads.In this mod-el,tools are treated failures when the torsion stress in tools exceeds the critical fatiguestress.A load-strength interference model is also included.The correlation of cutting edges is also taken into account using a cascade system,based on the cu-mulative distribution function and the probability density function which achieved on the equivalent loads.The sample val-ues of the critical fatigue stress and the stress distribution in the cutting head can be acquired by Monte Carlo simulation. The cutting parameters are determined by the cutting tests.Thus the service life and reliability of the cutting tools can be calculated by combining the sample mechanical values with the cutting parameters.Finally,the correctness of the model is verified by the constant stress accelerated life tests.