摘要
采用裂纹圆棒(CRB)试验法对PE100管材热熔对接接头进行了不同载荷比的疲劳裂纹扩展(FCG)试验,研究了此对接接头的疲劳裂纹扩展机制,并通过外推法得到静载荷下的抗慢速裂纹扩展(SCG)性能。结果表明:当载荷比R相同时,随着最大初始应力强度因子K_(max)的增大,PE100管材热熔对接接头的疲劳裂纹扩展速率增大,疲劳寿命缩短;当K_(max)相同时,随着R的增大,疲劳裂纹扩展速率减小,疲劳寿命增大;裂纹逐步扩展区银纹纤维拉伸长度的减小与裂纹稳定扩展区次生裂纹与主裂纹叠加均加快了热熔接头的裂纹扩展速率;利用外推法得到静载下使用寿命为50a时所允许的最大初始应力强度因子为0.555 MPa·m^(1/2)。
The cracked round bar（CRB）method was used to test the fatigue crack growth（FCG）behavior of PE100 pipe butt-fusion joint under different load ratio.The fatigue crack propagation mechanism of PE100 pipe butt-fusion joint was discussed.The slow crack growth（SCG）resistance in static loading condition was obtained by extrapolation.The results show that when load ratio R was the same,the fatigue crack propagation rate of PE100 pipe butt-fusion joint increased and the fatigue life shortened with the increase of maximum initial stress intensity factor K_（max）.When K_（max） was the same,the fatigue crack propagation rate decreased and the fatigue life extended with the increase of R.The stretched length of crazing fibrils in the crack discontinuous growth region reduced and the secondary cracks overlaid the main crack in the crack stable growth region which accelerated the crack propagation rate of butt-fusion joint.The allowable maximum initial stress intensity factor was 0.555 MPa·m^（1/2） for the service life of 50 years under static loading condition calculated by extrapolation.
出处
《机械工程材料》
CSCD
北大核心
2017年第9期36-41,共6页
Materials For Mechanical Engineering
基金
国家质检总局科技计划基金资助项目(2013QK267)
