New Test Method to Obtain Strain Fatigue Properties of Materials Based on Millimeter-scaled Slice Specimens

doi:10.3901/JME.2018.10.068

Abstract

Abstract: It is difficult to obtain the strain fatigue properties of small-sized materials such as slice, thin-walled pipes, weld zone by the current test standards. A new strain-fatigue test method for millimeter-scaled notched slice specimens is proposed. For the method, a novel cyclic constitutive model for predicting cyclic constitutive relationships of materials due to strain energy separation function assumption is derived, and then two conversion equations by finite element method are obtained to transform the testing strain amplitude and average stress amplitude into real-axial strain amplitude and stress amplitude at the root of the notched specimens. According to the two equations, strain fatigue life curves of material Representative-Volume-Element (RVE) and parameters of Manson-Coffin model via the notched specimens are set up. A series of finite element simulations for different materials show that the cyclic constitutive model is universal effective for different dimensions of the self-similar notched slice specimens and different materials. Variable-amplitude strain fatigue tests and constant-amplitude strain fatigue tests were carried out for the millimeter-scaled notched slice specimens and traditional round bar specimens with symmetric strain-control for 316L stainless steel. The results show that the cyclic constitutive relationships predicted by the cyclic constitutive model and the fatigue life curves of the notched specimens are in good agreement with the experimental results from the traditional round bar specimens.

Key words: fatigue life, millimeter-scaled slice specimen, model for predicting material cyclic constitutive relationship, strain energy separation function, strain-fatigue test, transforming equations of strain amplitude and stress amplitude

CLC Number:

TG156

YIN Tao, CAI Lixun, CHEN Hui, YAO Di. New Test Method to Obtain Strain Fatigue Properties of Materials Based on Millimeter-scaled Slice Specimens[J]. Journal of Mechanical Engineering, 2018, 54(10): 68-77.

References

[1] 中国国家标准化管理委员会. GB/T 15248-2008, 金属材料轴向等幅低循环疲劳试验方法[S]. 北京:中国标准出版社,2008. Standardization Administration of the People's Republic of China. GB/T 15248-2008 The test method for axial loading constant-amplitude low-cycle fatigue of metallic materials[S]. Beijing:Standards Press of China,2008.
[2] British Standards Institution. ISO12106-2003,Metallic materials-fatigue testing-axial-train-controlled method[S]. Geneva:International Organization for Standardization,2003.
[3] HE C,HUANG C,LIU Y,et al. Effects of mechanical heterogeneity on the tensile and fatigue behaviours in a laser-arc hybrid welded aluminium alloy joint[J]. Materials & Design,2015,65:289-296.
[4] YE S,ZHANG X C,TU S T. Interaction between local plastic strain and multi-scale fatigue crack propagation behavior in titanium alloy TC4[J]. Applied Mechanics and Materials,2017,853(1):51-56.
[5] WISNER S B,REYNOLDS M B,ADAMSON R B. Fatigue behavior of irradiated and unirradiated zircaloy and zirconium[J]. American Society for Testing and Materials,1994,1:499-520.
[6] 李丹柯,蔡力勋. 锆合金薄片材料高温低周疲劳试验技术[J]. 试验技术与试验机,2007(4):16-20. LI Danke,CAI Lixun. On low cycle fatigue testing technique at elevated temperature based on slice specimen[J]. Test Technology and Testing Machine,2007(4):16-20.
[7] 蔡力勋,叶裕明,高庆,等. Zr-4合金薄片材料的应变疲劳与寿命估算[J]. 西安交通大学学报,2004,38(1):97-104. CAI Lixun,YE Yuming,GAO Qing. Strain fatigue and life estimate of Zr-4 alloy slice[J]. Journal of Xi'an Jiaotong University,2004,38(1):97-104.
[8] 叶裕明,蔡力勋,李聪. Zr-4合金小试样高温疲劳行为研究[J]. 核动力工程,2006,27(3):37-42. YE Yuming,CAI Lixun,LI Cong. LCF behavior of Zr-4 alloy at elevated temperature[J]. Nuclear Power Engineering,2006,27(3):37-42.
[9] 蔡力勋,范宣华,李聪. 高温对Zr-4合金低循环行为的影响[J]. 航空材料学报,2004,24(5):1-6. CAI Lixun,FAN Xuanhua,LI Cong. Effects of elevated temperatures on the low cycle behavior of Zr-4 alloy[J]. Journal of Aeronautical Materials,2004,24(5):1-6.
[10] CAI Lixun,YE Yuming,LI Cong. Low-cycle fatigue behavior of small slice specimens of Zr-4 alloy at elevated temperature[J]. Key Engineering Materials,2006,324-325:1241-1244.
[11] 黄学伟. 新结构材料力学行为的获取方法[D]. 成都:西南交通大学,2010. HUANG Xuewei. Experiment and simulation methods for investigate mechanicals behavior of new structural materials[D]. Chengdu:Southwest Jiaotong University,2010.
[12] 黄学伟,蔡力勋,包陈,等. Zr-Sn-Nb薄片合金高温低周疲劳行为[J]. 原子能科学技术,2010,44(1):60-64. HUANG Xuewei,CAI Lixun,BAO Chen,et al. Low cycle fatigue behavior of Zr-Sn-Nb slice alloy at elevated temperature[J]. Atomic Energy Science and Technology. 2010,44(1):60-64.
[13] 黄学伟,蔡力勋,梁波. 基于单轴漏斗试样的一种低周疲劳测试方法与应用[J]. 中国测试,2009,35(5):7-10. HUANG Xuewei,CAI Lixun,LIANG Bo. Low cycle fatigue test method based on uniaxial test strain of notch specimens and its application[J]. China Measurement & Test,2009,35(5):7-10.
[14] 贾琦. 异型试样疲劳与断裂性能测试方法研究与应用[D]. 成都:西南交通大学,2011. JIA Qi. Research and application of fatigue and fracture properties test method of non-conventional samples[D]. Chengdu:Southwest Jiaotong University. Master,2011.
[15] 贾琦,蔡力勋,包陈. 考虑循环塑性修正的薄片材料低周疲劳试验方法[J]. 工程力学,2014,31(1):218-223. JIA Qi,CAI Lixun,BAO Chen. A testing method to investigate low cycle fatigue behavior of slice materials based on cycling plasticity correction[J]. Engineering Mechanics,2014,31(1):218-223.
[16] HUTCHINSON J W. Singular behaviour at the end of a tensile crack in a hardening material[J]. Journal of the Mechanics and Physics of Solids,1968,16(1):13-31.
[17] 赵少汴. 局部应力应变法及其设计数据[J]. 机械设计,2000,17(2):1-3. ZHAO Shaobian. Local stress-strain method and design data[J]. Journal of Machine Design,2000,17(2):1-3.