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LSSVM-based approach for refining soil failure criteria and calculating safety factor of slopes

Shiguo XIAO; Shaohong LI

《结构与土木工程前沿(英文)》 2022年 第16卷 第7期   页码 871-881 doi: 10.1007/s11709-022-0863-8

摘要: The failure criteria of practical soil mass are very complex, and have significant influence on the safety factor of slope stability. The Coulomb strength criterion and the power-law failure criterion are classically simplified. Each one has limited applicability owing to the noticeable difference between calculated predictions and actual results in some cases. In the work reported here, an analysis method based on the least square support vector machine (LSSVM), a machine learning model, is purposefully provided to establish a complex nonlinear failure criterion via iteration computation based on strength test data of the soil, which is of more extensive applicability to many problems of slope stability. In particular, three evaluation indexes including coefficient of determination, mean absolute percentage error, and mean square error indicate that fitting precision of the machine learning-based failure criterion is better than those of the linear Coulomb criterion and nonlinear power-law criterion. Based on the proposed LSSVM approach to determine the failure criterion, the limit equilibrium method can be used to calculate the safety factor of three-dimensional slope stability. Analysis of results of the safety factor of two three-dimensional homogeneous slopes shows that the maximum relative errors between the proposed approach and the linear failure criterion-based method and the power-law failure criterion-based method are about 12% and 7%, respectively.

关键词: slope stability     safety factor     failure criterion     least square support vector machine    

Finite element analysis of stress concentrations and failure criteria in composite plates with circular

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 281-294 doi: 10.1007/s11465-014-0307-9

摘要:

In this study, the stress concentration factors (SCF) in cross-and-angle-ply laminated composite plates as well as in isotropic plates with single circular holes subjected to uniaxial loading is studied. A quadrilateral finite element of four-node with 32 degrees of freedom at each node, previously developed for the bending and mechanical buckling of laminated composite plates, is used to evaluate the stress distribution in laminated composite plates with central circular holes. Based up on the classical plate theory, the present finite element is a combination of a linear isoparametric membrane element and a high precision rectangular Hermitian element. The numerical results obtained by the present element compare favorably with those obtained by the analytic approaches published in literature. It is observed that the obtained results are very close to the reference results, which demonstrates the accuracy of the present element. Additionally, to determine the first ply failure (FPF) of laminated plate, several failure criterions are employed. Finally, to show the effect of ratio on the failure of plates, a number of figures are given for different fiber orientation angles.

关键词: laminated composite plates     stress concentration     geometric singularity     anisotropic effect    

海堤设防标准探讨

卢永金,,何友声,刘桦

《中国工程科学》 2005年 第7卷 第12期   页码 17-23

摘要:

调查分析了国内外海堤设防标准,把海堤破坏归结为6种模式,并分析风浪与潮位(流)对各种模式的影响,提出风浪与高潮遭遇概率粗略算法;根据海堤结构特点及其破坏模式,提出一种基于风浪与高潮遭遇概率,综合反映结构功能、使用要求与潜在风险,三层次设防的海堤设计标准,在此基础上提供了一种基于风险理论的海堤优化设计方法。

关键词: 海堤     设计标准     风浪     高潮     遭遇概率     破坏模式     风险     优化设计    

Numerical simulation and analysis for collapse responses of RC frame structures under earthquake

Fuwen ZHANG, Xilin LU, Chao YIN,

《结构与土木工程前沿(英文)》 2009年 第3卷 第4期   页码 364-369 doi: 10.1007/s11709-009-0061-y

摘要: In this paper, a discrete element model for collapse simulation of RC frame structure is constructed by discretizing the structure into a few elements and spring groups. This model introduces special hysteretic models of connected springs for arbitrary loading path and also takes into account reasonable failure criteria for springs considering coupling effect of shear and axial force. Based on the discrete element model, a computer program is developed to simulate the whole process of RC frame structures from initial state to collapse under earthquakes. Particularly, the contact-impact problem between discrete elements has been treated with effective measures. Then, the program is employed to study the collapse mechanism of a real building in Wenchuan earthquake-hit area; the result of which shows that the simulation program developed based on the new model can realistically simulate the seismic collapse process of RC frame structures.

关键词: discrete element method     failure criteria     contact-impact     simulation program    

Trapezoidal Intuitionistic Fuzzy Aggregation Operator Based on Choquet Integral and Its Application to Multi-Criteria

Xi-hua Li,Xiao-hong Chen

《工程管理前沿(英文)》 2015年 第2卷 第3期   页码 266-276 doi: 10.15302/J-FEM-2015048

摘要: The Choquet integral can serve as a useful tool to aggregate interacting criteria in an uncertain environment. In this paper, a trapezoidal intuitionistic fuzzy aggregation operator based on the Choquet integral is proposed for multi-criteria decision-making problems. The decision information takes the form of trapezoidal intuitionistic fuzzy numbers and both the importance and the interaction information among decision-making criteria are considered. On the basis of the introduction of trapezoidal intuitionistic fuzzy numbers, its operational laws and expected value are defined. A trapezoidal intuitionistic fuzzy aggregation operator based on the Choquet integral is then defined and some of its properties are investigated. A new multi-criteria decision-making method based on a trapezoidal intuitionistic fuzzy Choquet integral operator is proposed. Finally, an illustrative example is used to show the feasibility and availability of the proposed method.

关键词: multi-criteria decision making     trapezoidal intuitionistic fuzzy numbers     Choquet integral     fuzzy measure     aggregation operator    

Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 210-216 doi: 10.1007/s11709-012-0165-7

摘要: A uniaxial tension test is commonly used to determine the mechanical properties of steel, but it has no meaning for the response of the material in a structure. The test was developed as a consensus solution by producers, fabricators, designers and code writers, to have a standard by which similar materials could be compared to a common base. It does not represent the actual behavior of the steel in a structure, and was never intended to do so. To study the true behavior of the structure and how the material responds it would be better to determine the strains and deformations that will take place during actual service condition. Such characteristics reflect the real behavior, whether in the elastic or inelastic range. If stresses or forces are needed, these are easily determined by the value of the strain and the relevant material modulus, along with the type of cross section, whether elastic or inelastic. The paper addresses the properties of a range of structural steels, how these are incorporated into design standards and how the standards define deformation characteristics and demands for bolted and welded connections.

关键词: steel     stress-strain characteristics     tension test     strain design     actual behavior     improved design codes    

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

摘要:

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    

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

摘要: In this study, gradual and sudden reduction methods were combined to simulate a progressive failure in notched composite plates using a macro mechanics approach. Using the presented method, a progressive failure is simulated based on a linear softening law prior to a catastrophic failure, and thereafter, sudden reduction methods are employed for modeling a progressive failure. This combination method significantly reduces the computational cost and is also capable of simultaneously predicting the first and last ply failures (LPFs) in composite plates. The proposed method is intended to predict the first ply failure (FPF), LPF, and dominant failure modes of carbon/epoxy and glass/epoxy notched composite plates. In addition, the effects of mechanical properties and different stacking sequences on the propagation of damage in notched composite plates were studied. The results of the presented method were compared with experimental data previously reported in the literature. By comparing the numerical and experimental data, it is revealed that the proposed method can accurately simulate the failure propagation in notched composite plates at a low computational cost.

关键词: progressive failure     notched composite plate     Hashin failure criterion     macro mechanics approach     finite element method    

Obesity in China: its characteristics, diagnostic criteria, and implications

null

《医学前沿(英文)》 2015年 第9卷 第2期   页码 129-133 doi: 10.1007/s11684-015-0387-x

Diagnostic criteria of latent autoimmune diabetes in adults (LADA): a review and reflection

Yu Liao, Yufei Xiang, Zhiguang Zhou

《医学前沿(英文)》 2012年 第6卷 第3期   页码 243-247 doi: 10.1007/s11684-012-0201-y

摘要: Diabetes has become a major public health problem in China nowadays. There are almost 97 million diabetic patients nationwide. Latent autoimmune diabetes in adults (LADA) is a subtype of autoimmune diabetes. Although it has been reported for about 20 years, the diagnostic criteria of this disease remain controversial. The discussion mainly focused on serum autoantibodies, period of insulin need and age of diagnosis. Besides, β cell function, metabolic parameters, genetic factors and cell immunity may also contribute to the formulation of the criteria. Here, we aim to review and discuss the diagnostic criteria of latent autoimmune diabetes in adults.

关键词: LADA     diagnostic criteria     autoantibodies     insulin independence     age of diagnosis    

Bending failure performance of a shield tunnel segment based on full-scale test and numerical analysis

《结构与土木工程前沿(英文)》   页码 1033-1046 doi: 10.1007/s11709-023-0973-y

摘要: This study focuses on the bending failure performance of a shield tunnel segment. A full-scale test was conducted to investigate deformation and failure characteristics. During the loading, the bending failure process can be divided into four stages: the elastic stage, working stage with cracks, failure stage, and ultimate stage. The characteristic loads between contiguous stages are the cracking, failure, and ultimate loads. A numerical model corresponding to the test was established using the elastoplastic damage constitutive model of concrete. After a comparative analysis of the simulation and test results, parametric studies were performed to discuss the influence of the reinforcement ratio and proportion of tensile longitudinal reinforcement on the bearing capacity. The results indicated that the change in the reinforcement ratio and the proportion of tensile longitudinal reinforcement had little effect on the cracking load but significantly influenced the failure and ultimate loads of the segment. It is suggested that in the reinforcement design of the subway segment, the reinforcement ratio and the proportion of tensile longitudinal reinforcement can be chosen in the range of 0.7%–1.2% and 49%–55%, respectively, allowing the segment to effectively use the reinforcement and exert the design strength, thereby improving the bearing capacity of the segment.

关键词: shield tunnel     bearing capacity     failure mechanism     segment reinforcement    

Human health ambient water quality criteria for 13 heavy metals and health risk assessment in Taihu Lake

《环境科学与工程前沿(英文)》 2022年 第16卷 第4期 doi: 10.1007/s11783-021-1475-6

摘要:

• The concentrations of 13 heavy metals in Taihu Lake were analyzed.

关键词: Heavy metals     Human health ambient water quality criteria     Taihu Lake     Health risk assessment     Contribution rate    

Overview on acute-on-chronic liver failure

null

《医学前沿(英文)》 2016年 第10卷 第1期   页码 1-17 doi: 10.1007/s11684-016-0439-x

摘要:

Liver failure (LF) is defined as severe dysfunction in hepatic synthesis, detoxification, and metabolism induced by various etiologies. Clinical presentation of LF typically includes severe jaundice, coagulation disorder, hepatic encephalopathy, and ascites. LF can be classified into acute LF, acute-on-chronic LF (ACLF), and chronic LF. ACLF has been demonstrated as a distinct syndrome with unique clinical presentation and outcomes. The severity, curability, and reversibility of ACLF have attracted considerable attention. Remarkable developments in ACLF-related conception, diagnostic criteria, pathogenesis, and therapy have been achieved. However, this disease, especially its diagnostic criteria, remains controversial. In this paper, we systemically reviewed the current understanding of ACLF from its definition, etiology, pathophysiology, pathology, and clinical presentation to management by thoroughly comparing important findings between east and west countries, as well as those from other regions. We also discussed the controversies, challenges, and needs for future studies to promote the standardization and optimization of the diagnosis and treatment for ACLF.

关键词: liver failure     chronic liver failure     acute-on-chronic liver failure     diagnosis     prognosis     treatment    

Surficial stability analysis of soil slope under seepage based on a novel failure mode

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 712-726 doi: 10.1007/s11709-021-0729-5

摘要: Normally, the edge effects of surficial landslides are not considered in the infinite slope method for surficial stability analysis of soil slopes. In this study, the limit stress state and discrimination equation of an infinite slope under saturated seepage flow were analyzed based on the Mohr-Coulomb strength criterion. Therefore, a novel failure mode involving three sliding zones (upper tension zone, middle shear sliding zone, and lower compression zone) was proposed. Accordingly, based on the limit equilibrium analysis, a semi-analytical framework considering the edge effect for the surficial stability of a soil slope under downslope seepage was established. Subsequently, the new failure mode was verified via a numerical finite element analysis based on the reduced strength theory with ABAQUS and some simplified methods using SLIDE software. The results obtained by the new failure mode agree well with those obtained by the numerical analysis and traditional simplified methods, and can be efficiently used to assess the surficial stability of soil slopes under rainwater seepage. Finally, an evaluation of the infinite slope method was performed using the semi-analytical method proposed in this study. The results show that the infinite slope tends to be conservative because the edge effect is neglected, particularly when the ratio of surficial slope length to depth is relatively small.

关键词: soil slope     seepage     surficial failure mode     stress state     edge effects    

Study of high-strength CFRP bolted joints with failure- monitoring cone washers

Tsukasa KATSUMATA, Yoshihiro MIZUTANI, Akira TODOROKI, Ryosuke MATSUZAKI

《机械工程前沿(英文)》 2011年 第6卷 第3期   页码 272-276 doi: 10.1007/s11465-011-0231-1

摘要:

To increase the strength of carbon-fiber-reinforced plastic (CFRP) bolted joints, a method to increase the friction force between carbon-fiber-reinforced plastic members was proposed. The increase in failure load for the proposed joint was confirmed in finite-element method analyses and joint tests. Additionally, the feasibility of damage monitoring using surface strains of the cone washer was demonstrated.

关键词: composite     bolted joint     failure monitoring     finite-element method    

标题 作者 时间 类型 操作

LSSVM-based approach for refining soil failure criteria and calculating safety factor of slopes

Shiguo XIAO; Shaohong LI

期刊论文

Finite element analysis of stress concentrations and failure criteria in composite plates with circular

null

期刊论文

海堤设防标准探讨

卢永金,,何友声,刘桦

期刊论文

Numerical simulation and analysis for collapse responses of RC frame structures under earthquake

Fuwen ZHANG, Xilin LU, Chao YIN,

期刊论文

Trapezoidal Intuitionistic Fuzzy Aggregation Operator Based on Choquet Integral and Its Application to Multi-Criteria

Xi-hua Li,Xiao-hong Chen

期刊论文

Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

期刊论文

Integrated management of cardiac failure: the cardiac failure clinic

null

期刊论文

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

期刊论文

Obesity in China: its characteristics, diagnostic criteria, and implications

null

期刊论文

Diagnostic criteria of latent autoimmune diabetes in adults (LADA): a review and reflection

Yu Liao, Yufei Xiang, Zhiguang Zhou

期刊论文

Bending failure performance of a shield tunnel segment based on full-scale test and numerical analysis

期刊论文

Human health ambient water quality criteria for 13 heavy metals and health risk assessment in Taihu Lake

期刊论文

Overview on acute-on-chronic liver failure

null

期刊论文

Surficial stability analysis of soil slope under seepage based on a novel failure mode

期刊论文

Study of high-strength CFRP bolted joints with failure- monitoring cone washers

Tsukasa KATSUMATA, Yoshihiro MIZUTANI, Akira TODOROKI, Ryosuke MATSUZAKI

期刊论文