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Chinese Journal of Engineering Design  2019, Vol. 26 Issue (2): 223-229    DOI: 10.3785/j.issn.1006?754X.2019.02.014
General Parts Design     
Research on fracture behavior of metal pipe based on high and low frequency composite vibration
HUA Chun-jian1,2, WANG Chao-fan1,2, LU Yun-jian1,2
1.School of Mechanical Engineering, Jiangnan University, Wuxi 214122, China
2.Jiangsu Key Laboratory of Advarced Food Manufacturing Equipment & Technology, Jiangnan University, Wuxi 214122, China
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Abstract  A loading method based on high and low frequency composite vibration was proposed,which is pointing to the fatigue fracture problem of metal pipe structures with stress concentration effect subjected to complex alternating loads. The fracture behavior of metal pipe with V-shaped notch was explored by developing a high and low frequency composite vibration experimental device. Based on the composite vibration characteristics of metal pipes, a composite vibration frequency control curve which could improve the crack initiation rate and expansion stability of metal pipes was proposed. The mechanical system and the computer measurement and control system of the composite vibration experimental device were designed. The vibration fracture experiments were carried out on three different metal pipes of 6061 aluminum alloy, 45 steel and 304 stainless steel with prefabricated V-shaped notches. Meanwhile, in order to compare and analyze the special sections of different metal pipes, a method for measuring and evaluating the quality of pipe sections was put forward, and the geometric accuracy and fracture time of three kinds of metal pipe sections were measured and evaluated. The experimental results showed that the crack of metal pipe would initiate rapidly and expand smoothly under the given linearly decreasing low-frequency vibration load. At the same time, it was found that the fracture time of metal pipe was reduced greatly and the crack initiation rate was accelerated significantly due to the superimposed high-frequency vibration load which led to smaller instantaneous fracture area and smoother section of the pipes. The research results provide important reference significance for the life analysis of metal pipes under complex alternating loads and the anti-fatigue design of metal pipes in engineering applications.

Received: 30 July 2018      Published: 28 April 2019
CLC:  TG 111.91  
Cite this article:

HUA Chun-jian, WANG Chao-fan, LU Yun-jian. Research on fracture behavior of metal pipe based on high and low frequency composite vibration. Chinese Journal of Engineering Design, 2019, 26(2): 223-229.

URL:

https://www.zjujournals.com/gcsjxb/10.3785/j.issn.1006?754X.2019.02.014     OR     https://www.zjujournals.com/gcsjxb/Y2019/V26/I2/223


基于高低频复合振动的金属管材断裂行为研究

针对具有应力集中效应的金属管结构在承受复杂交变载荷时的疲劳断裂问题,提出一种基于高低频复合振动的加载方法,并通过自行研制的高低频复合振动实验装置,探究带V形切口金属管材的断裂行为。基于金属管材的复合振动特性,提出了一种可以提高金属管材裂纹萌生速率与扩展稳定性的复合振动频率控制曲线。设计了高低频复合振动实验装置的机械系统和计算机测控系统,并对预制V形切口的6061铝合金、45钢和304不锈钢三种不同金属管材进行了振动断裂实验研究。同时,为了对不同金属管材的特殊断面进行比较与分析,提出一种管材断面质量检测与评价方法,并对3种金属管材断面几何精度及断裂时间进行测量与评价。实验结果表明:在给定的线性递减的低频振动载荷作用下,金属管材裂纹会快速萌生并平稳扩展;在叠加高频振动载荷后,金属管材的断裂时间大幅缩短,其裂纹扩展速率显著加快,且管材的瞬断区较小、断面平整。研究结果对金属管材在复杂交变载荷下的寿命分析及在工程应用中的抗疲劳设计有重要的参考意义。
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