Assessment Method for Early Fatigue Failure of Crankshaft Based on Dispersion of Impact Energy

Considering scattering behaviors of strength and fatigue life characteristics of actual materials, a method for evaluating the early fatigue failure of crankshafts has been proposed. The micro-mechanism of the scatter of strength and life characteristics is the nonuniform distribution of microstruct...

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Main Author: LI Xiangzhe, LIANG Gang, ZHENG Xiaomei, XU Congcong, XU Jinquan
Format: Article
Language:zho
Published: Editorial Office of Journal of Shanghai Jiao Tong University 2025-01-01
Series:Shanghai Jiaotong Daxue xuebao
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Online Access:https://xuebao.sjtu.edu.cn/article/2025/1006-2467/1006-2467-59-1-111.shtml
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author LI Xiangzhe, LIANG Gang, ZHENG Xiaomei, XU Congcong, XU Jinquan
author_facet LI Xiangzhe, LIANG Gang, ZHENG Xiaomei, XU Congcong, XU Jinquan
author_sort LI Xiangzhe, LIANG Gang, ZHENG Xiaomei, XU Congcong, XU Jinquan
collection DOAJ
description Considering scattering behaviors of strength and fatigue life characteristics of actual materials, a method for evaluating the early fatigue failure of crankshafts has been proposed. The micro-mechanism of the scatter of strength and life characteristics is the nonuniform distribution of microstructures (including micro-defects) inside the material, which can be uniformly characterized by the probability distribution of initial damage. For the same grade of alloy, the median values of strength and fatigue life can be basically the same, but the dispersion can be significantly different, which must be determined by sufficient sampling tests. For a diesel engine crankshaft forging made of the 34CrNi3MoA alloy, the dispersion of fatigue limit was estimated based on the scatter of impact sampling test data, while the mean value of probability distribution of fatigue limit was determined by structural fatigue tests. The safety factor recommended in the conventional design manual only implicitly assumes material dispersion. Considering the actual dispersion of the tested material, the quantitative relationship between safety factor and reliability has been established. Early fatigue failure of the crankshaft can easily occur when the actual dispersion of material fails to meet the specified reliability requirement.
format Article
id doaj-art-952e522706dc4c748f34248a4faf09f1
institution Kabale University
issn 1006-2467
language zho
publishDate 2025-01-01
publisher Editorial Office of Journal of Shanghai Jiao Tong University
record_format Article
series Shanghai Jiaotong Daxue xuebao
spelling doaj-art-952e522706dc4c748f34248a4faf09f12025-02-06T09:45:28ZzhoEditorial Office of Journal of Shanghai Jiao Tong UniversityShanghai Jiaotong Daxue xuebao1006-24672025-01-0159111112010.16183/j.cnki.jsjtu.2023.203Assessment Method for Early Fatigue Failure of Crankshaft Based on Dispersion of Impact EnergyLI Xiangzhe, LIANG Gang, ZHENG Xiaomei, XU Congcong, XU Jinquan01. State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;2. Shanghai Marine Diesel Engine Research Institute, CSSC, Shanghai 201108, China;3. Beijing Aeronautical Engineering Technical Research Center, Beijing 100076,ChinaConsidering scattering behaviors of strength and fatigue life characteristics of actual materials, a method for evaluating the early fatigue failure of crankshafts has been proposed. The micro-mechanism of the scatter of strength and life characteristics is the nonuniform distribution of microstructures (including micro-defects) inside the material, which can be uniformly characterized by the probability distribution of initial damage. For the same grade of alloy, the median values of strength and fatigue life can be basically the same, but the dispersion can be significantly different, which must be determined by sufficient sampling tests. For a diesel engine crankshaft forging made of the 34CrNi3MoA alloy, the dispersion of fatigue limit was estimated based on the scatter of impact sampling test data, while the mean value of probability distribution of fatigue limit was determined by structural fatigue tests. The safety factor recommended in the conventional design manual only implicitly assumes material dispersion. Considering the actual dispersion of the tested material, the quantitative relationship between safety factor and reliability has been established. Early fatigue failure of the crankshaft can easily occur when the actual dispersion of material fails to meet the specified reliability requirement.https://xuebao.sjtu.edu.cn/article/2025/1006-2467/1006-2467-59-1-111.shtmlearly fatigue failuredispersionimpact energyfatigue limitreliability
spellingShingle LI Xiangzhe, LIANG Gang, ZHENG Xiaomei, XU Congcong, XU Jinquan
Assessment Method for Early Fatigue Failure of Crankshaft Based on Dispersion of Impact Energy
Shanghai Jiaotong Daxue xuebao
early fatigue failure
dispersion
impact energy
fatigue limit
reliability
title Assessment Method for Early Fatigue Failure of Crankshaft Based on Dispersion of Impact Energy
title_full Assessment Method for Early Fatigue Failure of Crankshaft Based on Dispersion of Impact Energy
title_fullStr Assessment Method for Early Fatigue Failure of Crankshaft Based on Dispersion of Impact Energy
title_full_unstemmed Assessment Method for Early Fatigue Failure of Crankshaft Based on Dispersion of Impact Energy
title_short Assessment Method for Early Fatigue Failure of Crankshaft Based on Dispersion of Impact Energy
title_sort assessment method for early fatigue failure of crankshaft based on dispersion of impact energy
topic early fatigue failure
dispersion
impact energy
fatigue limit
reliability
url https://xuebao.sjtu.edu.cn/article/2025/1006-2467/1006-2467-59-1-111.shtml
work_keys_str_mv AT lixiangzhelianggangzhengxiaomeixucongcongxujinquan assessmentmethodforearlyfatiguefailureofcrankshaftbasedondispersionofimpactenergy