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全寿命周期 4

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Bayes estimation of residual life by fusing multisource information

Qian ZHAO, Xiang JIA, Zhi-jun CHENG, Bo GUO

《工程管理前沿（英文）》 2018年 第5卷 第4期   页码 524-532 doi: 10.15302/J-FEM-2018034

摘要：

Residual life estimation is essential for reliability engineering. Traditional methods may experience difficulties in estimating the residual life of products with high reliability, long life, and small sample. The Bayes model provides a feasible solution and can be a useful tool for fusing multisource information. In this study, a Bayes model is proposed to estimate the residual life of products by fusing expert knowledge, degradation data, and lifetime data. The linear Wiener process is used to model degradation data, whereas lifetime data are described via the inverse Gaussian distribution. Therefore, the joint maximum likelihood (ML) function can be obtained by combining lifetime and degradation data. Expert knowledge is used according to the maximum entropy method to determine the prior distributions of parameters, thereby making this work different from existing studies that use non-informative prior. The discussion and analysis of different types of expert knowledge also distinguish our research from others. Expert knowledge can be classified into three categories according to practical engineering. Methods for determining prior distribution by using the aforementioned three types of data are presented. The Markov chain Monte Carlo is applied to obtain samples of the parameters and to estimate the residual life of products due to the complexity of the joint ML function and the posterior distribution of parameters. Finally, a numerical example is presented. The effectiveness and practicability of the proposed method are validated by comparing it with residual life estimation that uses non-informative prior. Then, its accuracy and correctness are proven via simulation experiments.

关键词： residual life estimation     Bayes model     linear Wiener process    

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Experimental study of surface integrity and fatigue life in the face milling of Inconel 718

Xiangyu WANG, Chuanzhen HUANG, Bin ZOU, Guoliang LIU, Hongtao ZHU, Jun WANG

《机械工程前沿（英文）》 2018年 第13卷 第2期   页码 243-250 doi: 10.1007/s11465-018-0479-9

摘要：

The Inconel 718 alloy is widely used in the aerospace and power industries. The machining-induced surface integrity and fatigue life of this material are important factors for consideration due to high reliability and safety requirements. In this work, the milling of Inconel 718 was conducted at different cutting speeds and feed rates. Surface integrity and fatigue life were measured directly. The effects of cutting speed and feed rate on surface integrity and their further influences on fatigue life were analyzed. Within the chosen parameter range, the cutting speed barely affected the surface roughness, whereas the feed rate increased the surface roughness through the ideal residual height. The surface hardness increased as the cutting speed and feed rate increased. Tensile residual stress was observed on the machined surface, which showed improvement with the increasing feed rate. The cutting speed was not an influencing factor on fatigue life, but the feed rate affected fatigue life through the surface roughness. The high surface roughness resulting from the high feed rate could result in a high stress concentration factor and lead to a low fatigue life.

关键词： roughness     hardness     residual stress     microstructure     fatigue life    

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Secondary transfer length and residual prestress of fractured strand in post-tensioned concrete beams

Lizhao DAI; Wengang XU; Lei WANG; Shanchang YI; Wen CHEN

《结构与土木工程前沿（英文）》 2022年 第16卷 第3期   页码 388-400 doi: 10.1007/s11709-022-0809-1

摘要： An experimental study is performed on five post-tensioned concrete beams to explore the effects of different fracture positions on secondary transfer length and residual prestress of fractured strand. A numerical model is developed and used to predict the secondary transfer length and residual prestress of fractured strand in post-tensioned concrete beams. The model change interaction, which can deactivate and reactivate the elements for simulating the removal and reproduction of parts of the model, is used to reproduce the secondary anchorage of fractured strand. The numerical model is verified by experimental results. Results shows that the fractured strand can be re-anchored in concrete through the secondary anchorage, and the secondary transfer length of fractured strand with the diameter of 15.2 mm is 1133 mm. The residual prestress of fractured strand increases gradually in the secondary transfer length, and tends to be a constant beyond it. When the fractured strand is fully anchored in concrete, a minor prestress loss will appear, and the average prestress loss is 2.28% in the present study.

关键词： post-tensioned concrete beams     strand fracture     secondary transfer length     residual prestress    

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Minimal residual disease in solid tumors: an overview

《医学前沿（英文）》 2023年 第17卷 第4期   页码 649-674 doi: 10.1007/s11684-023-1018-6

摘要： Minimal residual disease (MRD) is termed as the small numbers of remnant tumor cells in a subset of patients with tumors. Liquid biopsy is increasingly used for the detection of MRD, illustrating the potential of MRD detection to provide more accurate management for cancer patients. As new techniques and algorithms have enhanced the performance of MRD detection, the approach is becoming more widely and routinely used to predict the prognosis and monitor the relapse of cancer patients. In fact, MRD detection has been shown to achieve better performance than imaging methods. On this basis, rigorous investigation of MRD detection as an integral method for guiding clinical treatment has made important advances. This review summarizes the development of MRD biomarkers, techniques, and strategies for the detection of cancer, and emphasizes the application of MRD detection in solid tumors, particularly for the guidance of clinical treatment.

关键词： MRD     solid tumor     CTC     ctDNA    

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The formation mechanism and the influence factor of residual stress in machining

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 265-269 doi: 10.1007/s11465-014-0311-0

摘要：

Residual stresses generated in cutting process have important influences on workpiece performance. The paper presents a method of theoretical analysis in order to explicate the formation mechanism of residual stresses in cutting. An important conclusion is drawn that the accumulated plastic strain is the main factor which determines the nature and the magnitude of surface residual stresses in the workpiece. On the basis of the analytical model for residual stress, a series of simulations for residual stress prediction during cutting AISI 1045 steel are implemented in order to obtain the influences of cutting speed, depth of cut and tool edge radius on surface residual stress in the workpiece. And these influences are explained from the perspective of formation mechanism of residual stress in cutting. The conclusions have good applicability and can be used to guide the parameters selection in actual production.

关键词： residual stress     analytical model     strain     plastic     cutting parameter    

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Experiment and optimal design of a collection device for a residual plastic film baler

Qi NIU,Xuegeng CHEN,Chao JI,Jie WU

《农业科学与工程前沿（英文）》 2015年 第2卷 第4期   页码 347-354 doi: 10.15302/J-FASE-2015077

摘要： It is imperative to carry out research on residual plastic film collection technology to solve the serious problem of farmland pollution. The residual plastic film baler was designed as a package for film strip collection, cleaning and baling. The collection device is a core component of the baler. Response surface analysis was used in this study to optimize the structure and working parameters for improving the collection efficiency of residual film and the impurity of film package. The results show that the factors affecting the collection rate of residual film and the impurity of the film package are the speed ratio ( ) between the trash removal roller and eccentric collection mechanism, the number ( ) and the mounting angle ( ) of spring teeth in the same revolution plane. For the collection rate, the importance of the three factors are in the order, . Meanwhile, for the impurity, the importance of three factors are in the order, . When the speed ratio, the mounting angle and the number of spring teeth was set at 1.6°, 45°, and 8°, respectively, the collection rate of residual film was 88.9% and the impurity of residual film package was 14.2% for the baler.

关键词： residual film     collection device     collection rate of residual film     impurity of film package     optimization     baler    

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Improved analytical model for residual stress prediction in orthogonal cutting

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 249-256 doi: 10.1007/s11465-014-0310-1

摘要：

The analytical model of residual stress in orthogonal cutting proposed by Jiann is an important tool for residual stress prediction in orthogonal cutting. In application of the model, a problem of low precision of the surface residual stress prediction is found. By theoretical analysis, several shortages of Jiann’s model are picked out, including: inappropriate boundary conditions, unreasonable calculation method of thermal stress, ignorance of stress constraint and cyclic loading algorithm. These shortages may directly lead to the low precision of the surface residual stress prediction. To eliminate these shortages and make the prediction more accurate, an improved model is proposed. In this model, a new contact boundary condition between tool and workpiece is used to make it in accord with the real cutting process; an improved calculation method of thermal stress is adopted; a stress constraint is added according to the volume-constancy of plastic deformation; and the accumulative effect of the stresses during cyclic loading is considered. At last, an experiment for measuring residual stress in cutting AISI 1045 steel is conducted. Also, Jiann’s model and the improved model are simulated under the same conditions with cutting experiment. The comparisons show that the surface residual stresses predicted by the improved model is closer to the experimental results than the results predicted by Jiann’s model.

关键词： residual stress     analytical model     orthogonal cutting     cutting force     cutting temperature    

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Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked

Xiaobo REN, Odd M. AKSELSEN, B?rd NYHUS, Zhiliang ZHANG

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 217-223 doi: 10.1007/s11709-012-0169-3

摘要： Welding residual stress is one of the main concerns for fabrication and operation of steel structures due to its potential effect on structural integrity. This paper focuses on the effect of welding residual stress on the ductile crack growth resistance of circumferentially cracked steel pipes. Two-dimensional axi-symmetry model has been used to simulate the pipe. Residual stresses were introduced into the model by using so-called eigenstrain method. The complete Gurson model has been employed to calculate the ductile crack growth resistance. Results show that residual stresses reduce the ductile crack growth resistance. However, the effect of residual stresses on ductile crack growth resistance decreases with the increase of crack growth. The effect of residual stress has also been investigated for cases with different initial void volume fraction, material hardening and crack sizes.

关键词： residual stress     ductile crack growth resistance     complete Gurson model     eigenstrain method    

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An improved algorithm for McDowell’s analytical model of residual stress

null

《机械工程前沿（英文）》 2014年 第9卷 第2期   页码 150-155 doi: 10.1007/s11465-014-0295-9

摘要：

The analytical model for two-dimensional elastoplastic rolling/sliding contact proposed by McDowell is an important tool for predicting residual stress in rolling/sliding processes. In application of the model, a problem of low predicting precision near the surface layer of the component is found. According to the volume-constancy of plastic deformation, an improved algorithm for McDowell’s model is proposed in order to improve its predicting accuracy of the surface residual stress. In the algorithm, a relationship between three normal stresses perpendicular to each other at any point within the component is derived, and the relationship is applied to McDowell’s model. Meanwhile, an unnecessary hypothesis proposed by McDowell can be eliminated to make the model more reasonable. The simulation results show that the surface residual stress predicted by modified method is much closer to the FEM results than the results predicted by McDowell’s model under the same simulation conditions.

关键词： residual stress     McDowell’s model     volume-constancy of plastic deformation     FEM     elastoplastic rolling/sliding contact    

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Estimation of photolysis half-lives of dyes in a continuous-flow system with the aid of quantitative

Davoud BEIKNEJAD,Mohammad Javad CHAICHI

《环境科学与工程前沿（英文）》 2014年 第8卷 第5期   页码 683-692 doi: 10.1007/s11783-014-0680-y

摘要： In this paper the photolysis half-lives of the model dyes in water solutions and under ultraviolet (UV) radiation were determined by using a continuous-flow spectrophotometric method. A quantitative structure-property relationship (QSPR) study was carried out using 21 descriptors based on different chemometric tools including stepwise multiple linear regression (MLR) and partial least squares (PLS) for the prediction of the photolysis half-life ( ) of dyes. For the selection of test set compounds, a K-means clustering technique was used to classify the entire data set, so that all clusters were properly represented in both training and test sets. The QSPR results obtained with these models show that in MLR-derived model, photolysis half-lives of dyes depended strongly on energy of the highest occupied molecular orbital ( ), largest electron density of an atom in the molecule ( ) and lipophilicity (log ). While in the model derived from PLS, besides aforementioned and descriptors, the molecular surface area ( ), molecular weight ( ), electronegativity ( ), energy of the second highest occupied molecular orbital ( ) and dipole moment ( ) had dominant effects on logt values of dyes. These were applicable for all classes of studied dyes (including monoazo, disazo, oxazine, sulfonephthaleins and derivatives of fluorescein). The results were also assessed for their consistency with findings from other similar studies.

关键词： dye     photolysis half-life     quantitative structure-property relationship     continuous-flow     stepwise multiple linear regression     partial least squares    

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Multiscale model of micro curing residual stress evolution in carbon fiber-reinforced thermoset polymer

Xinyu HUI, Yingjie XU, Weihong ZHANG

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 475-483 doi: 10.1007/s11465-020-0590-6

摘要： In this study, the micro curing residual stresses of carbon fiber-reinforced thermoset polymer (CFRP) composites are evaluated using a multiscale modeling method. A thermochemical coupling model is developed at the macroscale level to obtain the distributions of temperature and degree of cure. Meanwhile, a representative volume element model of the composites is established at the microscale level. By introducing the information from the macroscale perspective, the curing residual stresses are calculated using the microscale model. The evolution of curing residual stresses reveals the interaction mechanism of fiber, matrix, and interphase period during the curing process. Results show that the curing residual stresses mostly present a tensile state in the matrix and a compressive state in the fiber. Furthermore, the curing residual stresses at different locations in the composites are calculated and discussed. Simulation results provide an important guideline for the analysis and design of CFRP composite structures.

关键词： CFRP     curing residual stress     multiscale modeling     finite element method    

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Effects of humic acid on residual Al control in drinking water treatment plants with orthophosphate addition

Wendong WANG, Hua LI, Zhenzhen DING, Xiaochang WANG, Rui LIU

《环境科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 470-476 doi: 10.1007/s11783-012-0422-y

摘要： This study aimed to investigate the effects of humic acid (HA) on residual Al control in drinking water facilities that used orthophosphate addition. The results showed that adding orthophosphate was an effective method for residual Al control for the raw water without HA. When orthophosphate was added at 1.0 min before the addition of poly aluminum chloride (PACl), the concentrations of soluble aluminum (Sol-Al) and total aluminum (Tot-Al) residue were 0.08 and 0.086 mg·L , respectively; both were reduced by 46% compared with the control experiment. The presence of HA would notably increase the residual Al concentration. For the raw water with 5 mg·L of HA, the concentrations of Sol-Al and Tot-Al increased from 0.136 and 0.174 mg·L to 0.172 and 0.272 mg·L , respectively. For water with a HA concentration above 5 mg·L , orthophosphate was ineffective in the control of residual Al, though there were still parts of orthophosphate were removed in coagulation. The amounts of Al removal were positively correlated with the solids freshly formed in coagulation. Similar to the raw water without HA, the best Al control was obtained with orthophosphate salt added at 1.0 min before PACl. HA concentrations in the raw water, solution pH, and the orthophosphate dosage suitable for residual Al control by orthophosphate precipitation were also investigated.

关键词： coagulation     drinking water     humic acid     orthophosphate     residual Al    

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Residual stresses in coating-based systems, part I: Mechanisms and analytical modeling

ZHANG Xiancheng, WU Yixiong, XU Binshi, WANG Haidou

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 1-12 doi: 10.1007/s11465-007-0001-2

摘要： Thin films and multi-layered coatings comprised of different classes of materials are often used for various functional devices. The thermo-mechanical integrity of these systems is becoming a major concern and is strongly related to the residual stresses because of the fabrication processes. In this paper, the sources of the residual stresses in the coating-based systems and the concept of misfit strain were briefly reviewed. Analytical models were developed to predict the residual stresses in multi-layered film structures or coating-based systems using the force and moment balances. In addition, the residual stress distributions in the func tionally and compositionally graded coatings were also analyzed.

关键词： briefly     different     thermo-mechanical integrity     addition     residual    

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impact analysis and multi-objective optimization design of Mg/Al assembled wheel considering riveting residual

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0701-7

摘要： The multi-material assembled light alloy wheel presents an effective lightweight solution for new energy vehicles, but its riveting connection remains a problem. To address this problem, this paper proposed the explicit riveting-implicit springback-implicit fatigue/explicit impact sequence coupling simulation analysis method, analyzed the fatigue and impact performance of the punching riveting connected magnesium/aluminum alloy (Mg/Al) assembled wheel, and constructed some major evaluation indicators. The accuracy of the proposed simulation method was verified by conducting physical experiments of single and cross lap joints. The punching riveting process parameters of the assembled wheel joints were defined as design variables, and the fatigue and impact performance of the assembled wheel was defined as the optimization objective. The connection-performance integration multi-objective optimization design of the assembled wheel considering riveting residual stress was designed via Taguchi experiment, grey relational analysis, analytic hierarchy process, principal component analysis, and entropy weighting methods. The optimization results of the three weighting methods were compared, and the optimal combination of design variables was determined. The fatigue and impact performance of the Mg/Al assembled wheel were effectively improved after optimization.

关键词： magnesium/aluminum assembled wheel     riveting residual stress     fatigue analysis     impact analysis     multi-objective optimization    

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Whole-life Thinking and Engineering the Future

Roger Flanagan

《工程管理前沿（英文）》 2014年 第1卷 第3期   页码 290-296 doi: 10.15302/J-FEM-2014040

摘要： Whole-life thinking for engineers working on the built environment has become more important in a fast changing world. Whole-life thinking is not new, every project attempts to balance the initial capital cost with the operating and maintenance cost of an asset. Engineers are increasingly concerned with complex systems, in which the parts interact with each other and with the outside world in many ways — the relationships between the parts determine how the system behaves. Systems thinking provides one approach to developing a more robust whole-life approach. Systems thinking is a process of understanding how things influence one another within a wider perspective. Complexity, chaos, and risk are endemic in all major projects. New approaches are needed to produce more reliable whole-life predictions. Best value, rather than lowest cost, can be achieved by using whole-life appraisal as a part of the design and delivery strategy.

关键词： whole-life thinking     systems thinking     complexity     chaos     risk management through life    

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标题 作者 时间 类型 操作

Bayes estimation of residual life by fusing multisource information

Qian ZHAO, Xiang JIA, Zhi-jun CHENG, Bo GUO

期刊论文

Experimental study of surface integrity and fatigue life in the face milling of Inconel 718

Xiangyu WANG, Chuanzhen HUANG, Bin ZOU, Guoliang LIU, Hongtao ZHU, Jun WANG

期刊论文

Secondary transfer length and residual prestress of fractured strand in post-tensioned concrete beams

Lizhao DAI; Wengang XU; Lei WANG; Shanchang YI; Wen CHEN

期刊论文

Minimal residual disease in solid tumors: an overview

期刊论文

The formation mechanism and the influence factor of residual stress in machining

null

期刊论文

Experiment and optimal design of a collection device for a residual plastic film baler

Qi NIU,Xuegeng CHEN,Chao JI,Jie WU

期刊论文

Improved analytical model for residual stress prediction in orthogonal cutting

null

期刊论文

Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked

Xiaobo REN, Odd M. AKSELSEN, B?rd NYHUS, Zhiliang ZHANG

期刊论文

An improved algorithm for McDowell’s analytical model of residual stress

null

期刊论文

Estimation of photolysis half-lives of dyes in a continuous-flow system with the aid of quantitative

Davoud BEIKNEJAD,Mohammad Javad CHAICHI

期刊论文

Multiscale model of micro curing residual stress evolution in carbon fiber-reinforced thermoset polymer

Xinyu HUI, Yingjie XU, Weihong ZHANG

期刊论文

Effects of humic acid on residual Al control in drinking water treatment plants with orthophosphate addition

Wendong WANG, Hua LI, Zhenzhen DING, Xiaochang WANG, Rui LIU

期刊论文

Residual stresses in coating-based systems, part I: Mechanisms and analytical modeling

ZHANG Xiancheng, WU Yixiong, XU Binshi, WANG Haidou

期刊论文

impact analysis and multi-objective optimization design of Mg/Al assembled wheel considering riveting residual

期刊论文

Whole-life Thinking and Engineering the Future

Roger Flanagan

期刊论文