深海热液采样阀PEEK阀芯疲劳寿命研究

Fatigue life of PEEK poppet for deep-sea hydrothermal fluid sampling valve

通过分析深海热液采样阀PEEK阀芯的实际工作情况,综合考虑几何尺寸、应力集中以及加载方式等因素的影响,研究PEEK阀芯在峰值为70MPa脉动工作压力下的疲劳寿命.运用传统名义应力法,由PEEK材料的应力-疲劳寿命曲线求得PEEK阀芯在工作过程中的应力-疲劳寿命曲线,结合疲劳损伤累积理论估算出阀芯的疲劳寿命.在实验中模拟取出样品过程,对同一批次的多个阀芯进行疲劳寿命试验,试验结果的一致性较好且与理论估算结果相吻合.PEEK阀芯在工作条件下的疲劳寿命为7个工作周期,阀芯的疲劳断裂符合疲劳损伤累积理论.

After analyzing the working cycles of the PEEK poppet of deep-sea hydrothermal sampling valves working in extreme temperature and pressure conditions,this work proposed an analytical method to predict the fatigue life of the PEEK poppet under varying working pressure with a maximum value of 70 MPa.The geometrical dimensions,stress concentration and loading styles of the PEEK poppet were comprehensively considered.By applying the traditional nominal stress method,the stress-fatigue life curve of the PEEK poppet during working cycles was obtained using the stress-fatigue life curve of the PEEK material.Then the fatigue life was estimated with the fatigue cumulative damage rule.A test rig was designed to imitate the sampling process,and the fatigue tests were performed on several poppets in the same manufacture series.The test results were consistent and agreed well with the analytical results.The fatigue life of the PEEK poppet is 7 cycles under the working condition,and the fatigue failure of the poppet accords with the fatigue cumulative damage rule.