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Fatigue features study on the crankshaft material of 42CrMo steel using acoustic emission
Yue SHI,Lihong DONG,Haidou WANG,Guolu LI,Shenshui LIU
《机械工程前沿（英文）》 2016年 第11卷 第3期 页码 233-241 doi: 10.1007/s11465-016-0400-3
Crankshaft is regarded as an important component of engines, and it is an important application of remanufacturing because of its high added value. However, the fatigue failure research of remanufactured crankshaft is still in its primary stage. Thus, monitoring and investigating the fatigue failure of the remanufacturing crankshaft is crucial. In this paper, acoustic emission (AE) technology and machine vision are used to monitor the four-point bending fatigue of 42CrMo, which is the material of crankshaft. The specimens are divided into two categories, namely, pre-existing crack and non-pre-existing crack, which simulate the crankshaft and crankshaft blank, respectively. The analysis methods of parameter-based AE techniques, wavelet transform (WT) and SEM analysis are combined to identify the stage of fatigue failure. The stage of fatigue failure is the basis of using AE technology in the field of remanufacturing crankshafts. The experiment results show that the fatigue crack propagation style is a transgranular fracture and the fracture is a brittle fracture. The difference mainly depends on the form of crack initiation. Various AE signals are detected by parameter analysis method. Wavelet threshold denoising and WT are combined to extract the spectral features of AE signals at different fatigue failure stages.
关键词： acoustic emission fatigue failure remanufacturing crankshaft wavelet analysis
林明,金平,孙明礼
《中国工程科学》 2001年 第3卷 第3期 页码 65-67
飞机使用环境谱中飞行环境谱和停放环境谱的组合就是飞行─停放─飞行环境谱。大多数军用飞机地面停放时间占飞机使用寿命的90％以上。海军飞机所处的高温、高湿、高盐雾腐蚀环境对飞机使用寿命有很大影响。腐蚀疲劳直接影响疲劳裂纹形成寿命。飞机使用寿命必须应用飞机使用环境谱，考虑飞行小时、日历时间和综合使用飞行小时。列举海军某直升机主桨毂轴向铰轴颈裂纹故障，通过波音公司飞机结构疲劳分析方法，在飞行小时、日历时间和综合使用飞行小时方面对其翻修期进行了探讨。
Durability of plasma-sprayed Cr3C2-NiCr coatings under rolling contact conditions
Xiancheng ZHANG, Fuzhen XUAN, Shantung TU, Binshi XU, Yixiong WU
《机械工程前沿（英文）》 2011年 第6卷 第1期 页码 118-135 doi: 10.1007/s11465-011-0127-0
The aim of this paper was to address the rolling contact fatigue (RCF) failure mechanisms of plasma-sprayed Cr3C2-NiCr coatings under different tribological conditions of contact stress. Weibull distribution plots of fatigue lives of the coated specimens at different contact stresses were obtained. The failure modes of coatings were identified on the basis of wore surface observations of the failed coatings. Results showed that the RCF failure modes can be classified into four main categories, i.e., surface abrasion, spalling, cohesive delamination, and interfacial delamination. The probabilities of the surface abrasion and spalling type failures were relatively high at low contact stress. When the coatings were subjected to abrasion and spalling type failures, the failure of the coating was depended on the microstrcture of the coating. The stress concentration near the micro-defects in the coating may be the may reason for the formation of spall. The coatings were prone to fail in delamination under higher contact stresses. However, the delamination of coating may be related to distribution of shear stress amplitude within coating. The location of maximum shear stress amplitude can be used as a key parameter to predict the initiation of subsurface cracks within coating in rolling contact.
关键词： rolling contact fatigue coating Weibull distribution failure mode mechanism
Integrated management of cardiac failure: the cardiac failure clinic
null
《医学前沿（英文）》 2011年 第5卷 第1期 页码 20-25 doi: 10.1007/s11684-011-0106-1
The prevalence of the risk factors and the risk of cardiac failure are both increasing in China. This might be the consequence of the changes of the life conditions (emigration to the urban areas, changes in the diet and life style, lack of physical exercise, etc.). The wide range of clinical presentations of cardiac failure (acute or chronic) and of therapeutic approaches (medical or surgical) makes necessary the integration within the same structure of the various experts involved in the diagnosis and the treatment of cardiac diseases. Technologic and human resources required to offer all the options represent a multifaceted commitment which should be focused optimally in dedicated centers. In these centers, collaboration should replace competition between the medical and the surgical cardiac specialists. Development of team work should permit to optimize the cost efficacy of the treatments. Most of all, such a structure will facilitate the translation of innovative therapies between the research centers and clinical facilities.
关键词： cardiac failure cardiac transplantation mechanical circulatory support
A dimensional analysis on asphalt binder fracture and fatigue cracking
Qian ZHAO, Zhoujing YE
《结构与土木工程前沿（英文）》 2018年 第12卷 第2期 页码 201-206 doi: 10.1007/s11709-017-0402-1
Hierarchical approach for fatigue cracking performance evaluation in asphalt pavements
Ibrahim ONIFADE, Yared DINEGDAE, Björn BIRGISSON
《结构与土木工程前沿（英文）》 2017年 第11卷 第3期 页码 257-269 doi: 10.1007/s11709-017-0410-1
关键词： fatigue cracking energy based crack initiation mechanistic approach pavement analysis
Assessment of fatigue life of remanufactured impeller based on FEA
Lei XU,Huajun CAO,Hailong LIU,Yubo ZHANG
《机械工程前沿（英文）》 2016年 第11卷 第3期 页码 219-226 doi: 10.1007/s11465-016-0394-x
Predicting the fatigue life of remanufactured centrifugal compressor impellers is a critical problem. In this paper, the S-N curve data were obtained by combining experimentation and theory deduction. The load spectrum was compiled by the rain-flow counting method based on the comprehensive consideration of the centrifugal force, residual stress, and aerodynamic loads in the repair region. A fatigue life simulation model was built, and fatigue life was analyzed based on the fatigue cumulative damage rule. Although incapable of providing a high-precision prediction, the simulation results were useful for the analysis of fatigue life impact factors and fatigue fracture areas. Results showed that the load amplitude greatly affected fatigue life, the impeller was protected from running at over-speed, and the predicted fatigue life was satisfied within the next service cycle safely at the rated speed.
关键词： remanufactured impeller fatigue life impeller failures finite element analysis (FEA)
詹俞,李国芬,王宏畅
《中国工程科学》 2013年 第15卷 第8期 页码 75-78
结合南京长江第四大桥钢桥面铺装实体工程，开展铺装层混合料20 ℃疲劳性能试验。为了使试验结果能够更真实地反映主桥铺装的实际情况，直接采用主桥铺装使用的混合料成型试件，其中，带钢板复合梁试件为施工现场摊铺、碾压成型。室内试验对铺装结构单层采用劈裂疲劳试验，选择0.2、0.3、0.4、0.5、0.6这5个等级的应力水平，对组合结构采用带钢板复合梁疲劳试验，荷载水平为6 kN、7 kN、8 kN，并通过回归分析得到疲劳方程。
Contact fatigue life prediction of a bevel gear under spectrum loading
Pan JIA, Huaiju LIU, Caichao ZHU, Wei WU, Guocheng LU
《机械工程前沿（英文）》 2020年 第15卷 第1期 页码 123-132 doi: 10.1007/s11465-019-0556-8
关键词： bevel gear rolling contact fatigue (RCF) multiaxial fatigue criterion load spectrum damage accumulation rule
Progressive failure analysis of notched composite plate by utilizing macro mechanics approach
《结构与土木工程前沿（英文）》 2021年 第15卷 第3期 页码 623-642 doi: 10.1007/s11709-021-0726-8
关键词： progressive failure notched composite plate Hashin failure criterion macro mechanics approach finite element method
Enhancing fatigue life of cylinder-crown integrated structure by optimizing dimension
Weiwei ZHANG,Xiaosong WANG,Zhongren WANG,Shijian YUAN
《机械工程前沿（英文）》 2015年 第10卷 第1期 页码 102-110 doi: 10.1007/s11465-015-0329-y
Cylinder-crown integrated hydraulic press (CCIHP) is a new press structure. The hemispherical hydraulic cylinder also functions as a main portion of crown, which has lower weight and higher section modulus compared with the conventional hydraulic cylinder and press crown. As a result, the material strength capacity is better utilized. During the engineering design of cylinder-crown integrated structure, in order to increase the fatigue life, structural optimization on the basis of the adaptive macro genetic algorithms (AMGA) is first conducted to both reduce weight and decrease peak stress. It is shown that the magnitude of the maximum principal stress is decreased by 28.6%, and simultaneously the total weight is reduced by 4.4%. Subsequently, strain-controlled fatigue test is carried out, and the stress-strain hysteresis loops and cyclic hardening curve are obtained. Based on linear fit, the fatigue properties are calculated and used for the fatigue life prediction. It is shown that the predicted fatigue life is significantly increased from 157000 to 1070000 cycles after structural optimization. Finally, according to the optimization design, a 6300 kN CCIHP has been manufactured, and priority application has been also suggested.
关键词： cylinder-crown integrated hydraulic press (CCIHP) adaptive macro genetic algorithms (AMGA) strain-controlled fatigue test
穆志韬
《中国工程科学》 2002年 第4卷 第3期 页码 68-72
依据海军现役飞机的腐蚀环境特点及结构件腐蚀损伤深度拟合规律，采用应力场强法和局部应力应变法分别对疲劳缺口系数Kf及疲劳寿命计算模型进行了分析，提出了一种腐蚀环境下飞机结构疲劳寿命的评定方法。该方法以室温大气环境下的寿命评定结论为依据，考虑了结构件腐蚀损伤后潮湿空气、盐雾、盐雾＋SO2等环境介质对疲劳寿命的影响，并结合国产某型飞机机翼前梁缘条腐蚀损伤部位的疲劳寿命及剩余寿命估算实例进行了分析。
Hyungjoo CHOI, Husam NAJM
《结构与土木工程前沿（英文）》 2020年 第14卷 第1期 页码 199-214 doi: 10.1007/s11709-019-0592-9
Jorge Alberto Rodriguez DURAN,Ronney Mancebo BOLOY,Rafael Raider LEONI
《机械工程前沿（英文）》 2015年 第10卷 第3期 页码 255-262 doi: 10.1007/s11465-015-0342-1
The well-known fatigue crack growth (FCG) curves are two-parameter dependents. The range of the stress intensity factor ?K and the load ratio R are the parameters normally used for describing these curves. For engineering purposes, the mathematical representation of these curves should be integrated between the initial and final crack sizes in order to obtain the safety factors for stresses and life. First of all, it is necessary to reduce the dependence of the FCG curves to only one parameter. ?K is almost always selected and, in these conditions, considered as the crack driving force. Using experimental data from literature, the present paper shows how to perform multiple regression analyses using the traditional Walker approach and the more recent unified approach. The correlations so obtained are graphically analyzed in three dimensions. Numerical examples of crack growth analysis for cracks growing under nominal stresses of constant amplitude in smooth and notched geometries are performed, assuming an identical material component as that of the available experimental data. The resulting curves of crack size versus number of cycles (a vs. N) are then compared. The two models give approximately the same (a vs. N) curves in both geometries. Differences between the behaviors of the (avs. N) curves in smooth and notched geometries are highlighted, and the reasons for these particular behaviors are discussed.
关键词： fatigue crack propagation modeling life prediction mean stress effects
标题 作者 时间 类型 操作
Fatigue features study on the crankshaft material of 42CrMo steel using acoustic emission
Yue SHI,Lihong DONG,Haidou WANG,Guolu LI,Shenshui LIU
期刊论文
Durability of plasma-sprayed Cr3C2-NiCr coatings under rolling contact conditions
Xiancheng ZHANG, Fuzhen XUAN, Shantung TU, Binshi XU, Yixiong WU
期刊论文
Hierarchical approach for fatigue cracking performance evaluation in asphalt pavements
Ibrahim ONIFADE, Yared DINEGDAE, Björn BIRGISSON
期刊论文
Assessment of fatigue life of remanufactured impeller based on FEA
Lei XU,Huajun CAO,Hailong LIU,Yubo ZHANG
期刊论文
Contact fatigue life prediction of a bevel gear under spectrum loading
Pan JIA, Huaiju LIU, Caichao ZHU, Wei WU, Guocheng LU
期刊论文
Enhancing fatigue life of cylinder-crown integrated structure by optimizing dimension
Weiwei ZHANG,Xiaosong WANG,Zhongren WANG,Shijian YUAN
期刊论文
Investigation of fatigue resistance of fillet-welded tube connection details for sign support structures
Hyungjoo CHOI, Husam NAJM
期刊论文
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