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LCF behavior and life prediction method of a single crystal nickel-based superalloy at high temperature

Zhihua ZHANG,Huichen YU,Chengli DONG

《机械工程前沿(英文)》 2015年 第10卷 第4期   页码 418-423 doi: 10.1007/s11465-015-0362-x

摘要:

Low cycle fatigue tests were conducted on the single crystal nickel-based superalloy, DD6, with different crystallographic orientations (i.e., [001], [011], and [111]) and strain dwell types (i.e., tensile, compressive, and balanced types) at a certain high temperature. Given the material anisotropy and mean stress, both orientation factor and stress range were introduced to the Smith, Watson, and Topper (SWT) stress model to predict the fatigue life. Experimental results indicated that the fatigue properties of DD6 depend on both crystallographic orientation and loading types. The fatigue life of the tensile, compressive, and balanced strain dwell tests are shorter than those of continuous cycling tests without strain dwell because of the important creep effect. The predicted results of the proposed modified SWT stress method agree well with the experimental data.

关键词: life prediction     single crystal superalloy     low cycle fatigue (LCF)     crystallographic orientation     strain dwell    

Evaluation method of multiaxial low cycle fatigue life for cubic single crystal material

CHEN Jiping, DING Zhiping

《机械工程前沿(英文)》 2007年 第2卷 第3期   页码 278-282 doi: 10.1007/s11465-007-0048-0

摘要: The coupling effect of normal stress and shear stress on orthotropic materials happens when applied loading deflects from the directions of the principal axes of the material coordinate system. By taking account of the coupling effects, formulas of equivalent stress and strain for cubic single crystal materials are cited. Using the equivalent strain and equivalent stress for such material and a variable k, which is introduced to express the effect of asymmetrical cyclic loading on fatigue life, a low cycle fatigue (LCF) life prediction model for such material in multiaxial stress starts is proposed. On the basis of the yield criterion and constitutive model of cubic single crystal materials, a subroutine to calculate the thermo elastic-plastic stress-strain of the material on an ANSYS platform was developed. The cyclic stress-strain of DD3 notched specimens under asymmetrical loading at 680vH was analyzed. Low cycle fatigue test data of the single crystal nickel-based superalloy are used to fit the different parameters of the power law with multiple linear regression analysis. The equivalent stress and strain for a cubic single crystal material as failure parameters have the largest correlation coefficient. A power law exists between k and the failure cycle. The model was validated with LCF test data of CMSX-2 and DD3 single crystal nickel-based superalloys. All the test data fall into the factor of 2.5 for CMSX-2 hollow cylinder specimens and 2.0 scatter band for DD3 notched specimens, respectively.

关键词: orthotropic     regression analysis     crystal material     multiaxial     prediction    

Life cycle cost savings analysis on traditional drainage systems from low impact development strategies

Pengfei ZHANG, Samuel T. ARIARATNAM

《工程管理前沿(英文)》 2021年 第8卷 第1期   页码 88-97 doi: 10.1007/s42524-020-0063-y

摘要: Areas that are covered with natural vegetation have been converted into asphalt, concrete, or roofed structures and have increased surface impermeability and decreased natural drainage capability. Conventional drainage systems were built to mimic natural drainage patterns to prevent the occurrence of waterlogging in developed sites. These drainage systems consist of two major components: 1) a stormwater conduit system, and 2) a runoff storage system. Runoff storage systems contain retention basins and drywells that are used to store and percolate runoff, whereas conduit systems are combination of catch basins and conduit pipes used to collect and transport runoff. The construction of these drainage systems is costly and may cause significant environmental disturbance. In this study, low impact development (LID) methods that consist of extensive green roofs (GRs) and permeable interlocking concrete pavements (PICPs) are applied in real-world construction projects. Construction project documents were reviewed, and related cost information was gathered through the accepted bidding proposals and interviews of specialty contractors in the metropolitan area of Phoenix, Arizona. Results indicate that the application of both LID methods to existing projects can save an average of 27.2% in life cycle costs (LCC) for a 50-year service life and 18.7% in LCC for a 25-year service life on the proposed drainage system, respectively.

关键词: low impact development     traditional drainage system     hydraulic benefits     life-cycle cost    

Fatigue of asphalt binder, mastic and mixture at low temperature

Dong WANG, Linbing WANG, Guoqing ZHOU

《结构与土木工程前沿(英文)》 2012年 第6卷 第2期   页码 166-175 doi: 10.1007/s11709-012-0157-7

摘要: The fatigue damage is one of the most common distresses observed on the asphalt concrete pavement. To thoroughly understand the fatigue of asphalt concrete, the behaviors of the major components of asphalt concrete under cyclic loading are investigated respectively in this study. A new experiment method is developed to evaluate the performances of asphalt binder, mastic and fine aggregates mixture under cyclic tensile loading. The fatigue test results of asphalt binder show that the fatigue performance of asphalt binder is closely related with loading magnitude, temperature and loading rate. Mastic specimens with different filler content are tested and the results indicate that mastic specimens with 30% filler content show better fatigue resistance and higher permanent strain. The micro-structure analysis of mastic and mixture indicates that the fatigue resistance is closely related with the air void content of specimen. 3D digital specimens are developed to model the fatigue of the asphalt binder, mastic and mixture specimens based on the finite element method (FEM). Fatigue damage of asphalt concrete is simplified by a damage model. With proper selection of damage parameters, the simulation results agree well with laboratory test results and can be used as a basis for future fatigue research.

关键词: fatigue     asphalt mixture     asphalt binder     mastic     finite element method (FEM)     X-ray tomography    

Life cycle assessment of low impact development technologies combined with conventional centralized water

Hyunju Jeong, Osvaldo A. Broesicke, Bob Drew, Duo Li, John C. Crittenden

《环境科学与工程前沿(英文)》 2016年 第10卷 第6期 doi: 10.1007/s11783-016-0851-0

摘要: Hybrid system of LID technologies and conventional system was examined. Bioretention areas, rainwater harvesting, and xeriscaping were considered. Technology feasibility was simulated for land use and population density. Synergistic effects of technologies were quantified in defined zones. Uncertainty test was conducted with pedigree matrix and Monte Carlo analysis. Low-impact development (LID) technologies, such as bioretention areas, rooftop rainwater harvesting, and xeriscaping can control stormwater runoff, supply non-potable water, and landscape open space. This study examines a hybrid system (HS) that combines LID technologies with a centralized water system to lessen the burden on a conventional system (CS). CS is defined as the stormwater collection and water supply infrastructure, and the conventional landscaping choices in the City of Atlanta. The study scope is limited to five single-family residential zones (SFZs), classified R-1 through R-5, and four multi-family residential zones (MFZs), classified RG-2 through RG-5. Population density increases from 0.4 (R-1) to 62.2 (RG-5) persons per 1,000 m . We performed a life cycle assessment (LCA) comparison of CS and HS using TRACI 2.1 to simulate impacts on the ecosystem, human health, and natural resources. We quantified the impact of freshwater consumption using the freshwater ecosystem impact (FEI) indicator. Test results indicate that HS has a higher LCA single score than CS in zones with a low population density; however, the difference becomes negligible as population density increases. Incorporating LID in SFZs and MFZs can reduce potable water use by an average of 50% and 25%, respectively; however, water savings are negligible in zones with high population density (i.e., RG-5) due to the diminished surface area per capita available for LID technologies. The results demonstrate that LID technologies effectively reduce outdoor water demand and therefore would be a good choice to decrease the water consumption impact in the City of Atlanta.

关键词: Life cycle assessment (LCA)     Low impact development (LID)     Bioretention area     Rainwater harvesting     Xeriscaping    

新型热轧低碳TRIP 钢的轧制工艺与疲劳性能

刘自权,谭小东,杨小龙,许云波,吴迪,王国栋

《中国工程科学》 2014年 第16卷 第1期   页码 54-58

摘要:

对比研究了现场不同工艺所得碳锰系车轮用钢及低碳低硅含磷铬系相变诱发塑性(TRIP)钢的力学性能、微观组织、疲劳性能和疲劳断口。结果显示,较传统碳锰系车轮用钢,新型TRIP 钢具有相当的屈服强度,抗拉强度明显提高了100~150 MPa,疲劳极限提高了50~140 MPa。疲劳极限随抗拉强度的提高有增大趋势。铁素体、贝氏体、残余奥氏体组织较铁素体、贝氏体、珠光体组织和铁素体、珠光体、马奥岛组织具有更好的疲劳性能。

关键词: 热轧     低碳TRIP钢     轧制工艺     疲劳性能     疲劳断口    

STRATEGIES FOR A LOW-CARBON FOOD SYSTEM IN CHINA

《农业科学与工程前沿(英文)》 2023年 第10卷 第2期   页码 167-182 doi: 10.15302/J-FASE-2023494

摘要:

● A provincial stage-specific greenhouse gas (GHG) accounting model for the Chinese food system was developed.

关键词: greenhouse gas emissions     food system     life cycle assessment     environmental input-output analysis     mitigation strategies    

A two-stage deep freezing chemisorption cycle driven by low-temperature heat source

Yuanyang HU, Liwei WANG, Lu XU, Ruzhu WANG, Jeremiah KIPLAGAT, Jian WANG

《能源前沿(英文)》 2011年 第5卷 第3期   页码 263-269 doi: 10.1007/s11708-011-0152-z

摘要: A two-stage chemisorption cycle suitable for deep-freezing application driven by low- temperature heat source was proposed. Through two-stage desorption processes, the two-stage cycle can break through the limitations of the heating temperature and ambient cooling temperature. The two-stage cycle based on CaCl /BaCl -NH working pair can utilize the heat source with a temperature of above 75°C, and simultaneously realize deep-freezing all the year round. Experimental results and performance prediction show that the adsorption quantity of calcium, theoretical coefficient of performance (COP) and optimized specific cooling power (SCP) of the CaCl /BaCl -NH chemisorption system are 0.489 kg/kg (salt), 0.24 and 120.7 W/kg, when the heating temperature, ambient cooling temperature, pseudo-evaporating temperature and mass ratio of reacting salt and expanded graphite are 85, 30, -20, and 4∶1, respectively.

关键词: adsorption     freezing     desorption     heat source    

中国汽车低碳化系统工程研究

张晓艳,王永军,李骏,付磊

《中国工程科学》 2018年 第20卷 第1期   页码 23-29 doi: 10.15302/J-SSCAE-2018.01.004

摘要:

中国已经签署《巴黎协定》并做出CO2减排承诺,中国汽车工业应该为实现中国低碳化作贡献。本文从中国汽车低碳化系统构架、生命周期碳排放现状和2030年中国汽车销量预测三个角度出发,构建了汽车CO2排放预测模型,分析了中国汽车碳排放构成,进行了至2030年汽车碳排放总量预测,预测结果显示,中国汽车碳排放总量在2025—2030年达到峰值。本研究建立了汽车低碳化评价体系,并提出了中国汽车低碳化技术路线的建议。

关键词: 低碳化     油耗法规     汽车技术     生命周期     技术路线    

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

摘要: Fracture and fatigue cracking in asphalt binder are two of most serious problems for pavement engineers. In this paper, we present a new comprehensive approach, which consists both of dimensional analysis using Buckingham Theorem and -integral analysis based on classic fracture mechanics, to evaluate the fracture and fatigue on asphalt binder. It is discovered that the dimensional analysis could provide a new perspective to analyze the asphalt fracture and fatigue cracking mechanism.

关键词: Dimensional analysis     asphalt     fracture     fatigue cracking    

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

摘要: In this paper, a hierarchical approach is proposed for the evaluation of fatigue cracking in asphalt concrete pavements considering three different levels of complexities in the representation of the material behaviour, design parameters characterization and the determination of the pavement response as well as damage computation. Based on the developed hierarchical approach, three damage computation levels are identified and proposed. The levels of fatigue damage analysis provides pavement engineers a variety of tools that can be used for pavement analysis depending on the availability of data, required level of prediction accuracy and computational power at their disposal. The hierarchical approach also provides a systematic approach for the understanding of the fundamental mechanisms of pavement deterioration, the elimination of the empiricism associated with pavement design today and the transition towards the use of sound principles of mechanics in pavement analysis and design.

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

摘要:

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)    

南京长江第四大桥钢桥面铺装疲劳性能试验研究

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

摘要:

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。

关键词: 道路工程     钢桥面铺装     疲劳性能     劈裂疲劳     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

摘要: Rolling contact fatigue (RCF) issues, such as pitting, might occur on bevel gears because load fluctuation induces considerable subsurface stress amplitudes. Such issues can dramatically affect the service life of associated machines. An accurate geometry model of a hypoid gear utilized in the main reducer of a heavy-duty vehicle is developed in this study with the commercial gear design software MASTA. Multiaxial stress–strain states are simulated with the finite element method, and the RCF life is predicted using the Brown–Miller–Morrow fatigue criterion. The patterns of fatigue life on the tooth surface are simulated under various loading levels, and the RCF curve is numerically generated. Moreover, a typical torque–time history on the driven axle is described, followed by the construction of program load spectrum with the rain flow method and the Goodman mean stress equation. The effects of various fatigue damage accumulation rules on fatigue life are compared and discussed in detail. Predicted results reveal that the Miner linear rule provides the most optimistic result among the three selected rules, and the Manson bilinear rule produces the most conservative result.

关键词: bevel gear     rolling contact fatigue (RCF)     multiaxial fatigue criterion     load spectrum     damage accumulation rule    

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

摘要:

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    

标题 作者 时间 类型 操作

LCF behavior and life prediction method of a single crystal nickel-based superalloy at high temperature

Zhihua ZHANG,Huichen YU,Chengli DONG

期刊论文

Evaluation method of multiaxial low cycle fatigue life for cubic single crystal material

CHEN Jiping, DING Zhiping

期刊论文

Life cycle cost savings analysis on traditional drainage systems from low impact development strategies

Pengfei ZHANG, Samuel T. ARIARATNAM

期刊论文

Fatigue of asphalt binder, mastic and mixture at low temperature

Dong WANG, Linbing WANG, Guoqing ZHOU

期刊论文

Life cycle assessment of low impact development technologies combined with conventional centralized water

Hyunju Jeong, Osvaldo A. Broesicke, Bob Drew, Duo Li, John C. Crittenden

期刊论文

新型热轧低碳TRIP 钢的轧制工艺与疲劳性能

刘自权,谭小东,杨小龙,许云波,吴迪,王国栋

期刊论文

STRATEGIES FOR A LOW-CARBON FOOD SYSTEM IN CHINA

期刊论文

A two-stage deep freezing chemisorption cycle driven by low-temperature heat source

Yuanyang HU, Liwei WANG, Lu XU, Ruzhu WANG, Jeremiah KIPLAGAT, Jian WANG

期刊论文

中国汽车低碳化系统工程研究

张晓艳,王永军,李骏,付磊

期刊论文

A dimensional analysis on asphalt binder fracture and fatigue cracking

Qian ZHAO, Zhoujing YE

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

南京长江第四大桥钢桥面铺装疲劳性能试验研究

詹俞,李国芬,王宏畅

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