资源类型

期刊论文 328

会议视频 5

年份

2024 1

2023 22

2022 29

2021 30

2020 15

2019 23

2018 8

2017 10

2016 22

2015 11

2014 11

2013 10

2012 24

2011 7

2010 21

2009 14

2008 16

2007 15

2006 12

2005 3

展开 ︾

关键词

DX桩 11

承载力 9

沉降 5

大气污染 4

发展 3

“一带一路” 2

仿真 2

动力气垫 2

地效翼船 2

应用 2

影响因素 2

悬索桥 2

抗拔 2

振动 2

数值分析 2

数值模拟 2

极限承载力 2

温度控制 2

育龄妇女 2

展开 ︾

检索范围：

排序： 展示方式：

Air-bearing position optimization based on dynamic characteristics of ultra-precision linear stages

CHEN Xuedong, LI Zhixin

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 400-407 doi: 10.1007/s11465-008-0060-z

摘要： Air-bearings are installed between the stator and the mover of ultra-precision linear stages to suppress vibration and mechanical contact. Spring-damping elements are used to emulate the complex interaction of the finite element model (FEM) developed in this paper and the system dynamic behaviors are analyzed. Through the experimental modal test, the validity and reliability of the model are proven. However, the dynamic characteristics including mode frequency, mode shape, and response amplitude are obviously changed with the position of air-bearings. The combined optimization method is used to optimize the air-bearings position. The best and worst positions are obtained using the dynamic characteristic analysis. The method can be generalized to the connection position of different components in manufacture elements and to implement the system dynamic characteristics optimization when the connection position can be changed.

关键词： manufacture     different     interaction     air-bearings     response amplitude    

HTML PDF 收藏

Model reduction techniques for dynamics analysis of ultra-precision linear stage

Xuedong CHEN, Zhixin LI

《机械工程前沿（英文）》 2009年 第4卷 第1期   页码 64-70 doi: 10.1007/s11465-009-0009-x

摘要： Spring-damping elements are used to simplify the internal interaction in the proposed finite element (FE) model of an ultra-precision linear stage. The dynamics behavior is studied. The comparison between mode shapes from the eigenvalue analysis shows that the components, except the translator, can represent system dynamics characteristics. A reduction approach is used to simplify the system in a dynamic studied. There is little difference between the vibration mode and the response analysis. The experimental modal analysis proves the validity of the reduction approach, which can be generalized to the development and dynamics characteristic study of a complex system model to obviously save computational resource.

关键词： dynamics analysis     air-bearing     linear stage     reduction    

HTML PDF 收藏

API-based assessment on urban air environment bearing capability in China

Jinnan WANG,Jing ZHANG,Hongqiang JIANG,Yaling LU

《环境科学与工程前沿（英文）》 2015年 第9卷 第6期   页码 1049-1055 doi: 10.1007/s11783-014-0662-0

摘要： Given the complexity and time-consuming of the conventional environmental capacity based assessment on air environment carrying capacity; a new method for assessing urban air environment carrying capacity based on air pollution index (API) is presented. By using this new method, the air environmental bearing capability of 333 cities at the prefecture level and above is assessed. The results show that of the 333 cities 9.6% is of high bearing capability, 34.5% relatively high bearing capability, 52.6% medium bearing capability, 2.7% low capability, and 0.6% is of weak bearing capability; in terms of regional distribution, the western region is of relatively high air environment bearing capability, followed by north-eastern and eastern regions, and the ambient air quality in the middle region is quite poor; among the 12 urban agglomerations in key regions, Pearl River delta, west side of Taiwan Strait and Chengdu-Chongqing agglomerations are of relatively high carrying capacity while other agglomerations are of medium bearing capability. The assessment results imply that the existing air quality standard (GB3095-1996) is quite unsound.

关键词： air pollution index (API)     air environment bearing capability     key city     assessment method    

HTML PDF 收藏

Electrorheological damper for the ultra-precision air bearing stage

ZHU Yu, JIA Songtao, CHEN Yaying, LI Guang

《机械工程前沿（英文）》 2008年 第3卷 第2期   页码 158-163 doi: 10.1007/s11465-008-0031-4

摘要： This paper illustrates how the electrorheological damper substantially improves the performance of the ultra-precision air bearing stage. Smart materials such as electrorheological fluids have attracted many researchers’ attention because of their resistance changeable performance in different electric fields. Meanwhile, the ultra-precision air bearing stage driven by the linear-motor is characterized by zero mechanical damping and poor anti-disturbance. To solve this problem and consider the characteristics of electrorheological fluids, an electrorheological damper is proposed in this paper. The electrorheological damper’s characteristics in high electric fields are obtained based on the Eyring constitutive model, which smoothly transits from the pre-yield to post-yield region. To enhance the performance of the electrorheological damper, which takes effect only when the stage is going to decelerate or position, the on-off and sliding mode control methods design and optimize the controller. The results prove that by using the advanced sliding mode control method, the characteristics of the ultra-precision air bearing stage can be effectively improved through the introduction of the electrorheological damper.

关键词： post-yield     linear-motor     advanced sliding     pre-yield     position    

HTML PDF 收藏

Air bearing center cross gap of neutron stress spectrometer sample table support system

Yang LI,Yunxin WU,Hai GONG,Xiaolei FENG

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 403-411 doi: 10.1007/s11465-016-0405-y

摘要：

A support system is the main load-bearing component of sample table for neutron stress spectrometer, and air bearing is an important element of a support system. The neutron stress spectrometer sample table was introduced, and the scheme for air bearing combination was selected. To study the performance of air bearing center cross gap, finite element models (FEMs) were established based on air motion and Reynolds equations, effects of air supply pressure, and gap parameters on the overturning moment and bearing capacity of air bearing center cross gap were analyzed. Results indicate that the width, depth, and height differences of the marble floor gap played important roles in the performance of the air bearing. When gap width is lesser than 1 mm and gap depth is lower than 0.4 mm, bearing capacity and overturning moment would vary rapidly with the variation of the width and depth. A gap height difference results in the bearing capacity dropping rapidly. The FEM results agree well with experimental results. Further, findings of the study could guide the design of the support system and marble floor.

关键词： neutron stress spectrometer     sample table     support system     air bearing     center cross gap     simulation     experiment    

HTML PDF 收藏

Iterative HOEO fusion strategy: a promising tool for enhancing bearing fault feature

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0725-z

摘要： As parameter independent yet simple techniques, the energy operator (EO) and its variants have received considerable attention in the field of bearing fault feature detection. However, the performances of these improved EO techniques are subjected to the limited number of EOs, and they cannot reflect the non-linearity of the machinery dynamic systems and affect the noise reduction. As a result, the fault-related transients strengthened by these improved EO techniques are still subject to contamination of strong noises. To address these issues, this paper presents a novel EO fusion strategy for enhancing the bearing fault feature nonlinearly and effectively. Specifically, the proposed strategy is conducted through the following three steps. First, a multi-dimensional information matrix (MDIM) is constructed by performing the higher order energy operator (HOEO) on the analysis signal iteratively. MDIM is regarded as the fusion source of the proposed strategy with the properties of improving the signal-to-interference ratio and suppressing the noise in the low-frequency region. Second, an enhanced manifold learning algorithm is performed on the normalized MDIM to extract the intrinsic manifolds correlated with the fault-related impulses. Third, the intrinsic manifolds are weighted to recover the fault-related transients. Simulation studies and experimental verifications confirm that the proposed strategy is more effective for enhancing the bearing fault feature than the existing methods, including HOEOs, the weighting HOEO fusion, the fast Kurtogram, and the empirical mode decomposition.

关键词： higher order energy operator     fault diagnosis     manifold learning     rolling element bearing     information fusion    

HTML PDF 收藏

New analysis model for rotor-bearing systems based on plate theory

Zhinan ZHANG, Mingdong ZHOU, Weimin DING, Huifang MA

《机械工程前沿（英文）》 2019年 第14卷 第4期   页码 461-473 doi: 10.1007/s11465-019-0525-2

摘要： The purpose of this work is to develop a new analysis model for angular-contact, ball-bearing systems on the basis of plate theory instead of commonly known approaches that utilize spring elements. Axial and radial stiffness on an annular plate are developed based on plate, Timoshenko beam, and plasticity theories. The model is developed using theoretical and inductive methods and validated through a numerical simulation with the finite element method. The new analysis model is suitable for static and modal analyses of rotor-bearing systems. Numerical examples are presented to reveal the effectiveness and applicability of the proposed approach.

关键词： rotor-bearing system     rolling element bearing     plate theory     finite element analysis    

HTML PDF 收藏

The convexity about ultimate bearing hypersurfaces of structures

Chengxi GUO,Tingting GUO

《结构与土木工程前沿（英文）》 2016年 第10卷 第4期   页码 456-461 doi: 10.1007/s11709-016-0334-1

摘要： The relationship between the convexity on the ultimate bearing surface of a structure and the second-order effects of loads is discussed. All of generalized non-overload forces acted on a structure forms a convex set when ignoring the second-order effects (coupling effects between the generalized forces). It is true also when the Hessian matrix composed of the second-order partial derivatives on the hypersurface about the ultimate bearing of the structure is negative definite. The outward convexity is kept when the surface is expressed by certain dimensionless parameters. A series of properties based on the convexity are pointed out. Some applications in the analysis of bearing capacity of structures were illustrated with examples. The study shows that an evaluation about the bearing capacity state of a complex structure can be made on the basis of several points on the surface of the ultimate bearing of the structure.

关键词： service     limit load     ultimate bearing surface     convexity     generalized force     generalized displacement     frame structure    

HTML PDF 收藏

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 446-455 doi: 10.1007/s11709-013-0227-5

摘要： An estimate of the ultimate load on foundations on soil layers subject to groundwater flow has been presented. The kinematic approach of the limit analysis was employed to find the upper-bound limit of the bearing capacity. Both smooth and rough base strip foundations were considered associated with different collapse patterns. Presence of the groundwater flow leads to a non-symmetric collapse pattern, i.e., a weak side and a strong side in two-sided collapse patterns, depending on the direction of the flow. It was found that the bearing capacity has a decreasing trend with increase in the groundwater flow gradient and hence, a reduction factor has been introduced to the third term in the bearing capacity equation as a function of the flow gradient.

关键词： foundation     bearing capacity     limit analysis     numerical computation     plasticity     seepage    

HTML PDF 收藏

Undrained seismic bearing capacity of strip footing adjacent to a heterogeneous excavation

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 566-583 doi: 10.1007/s11709-023-0905-x

摘要： The analysis of the bearing capacity of strip footings sited near an excavation is critical in geotechnics. In this study, the effects of the geometrical features of the excavation and the soil strength properties on the seismic bearing capacity of a strip footing resting on an excavation were evaluated using the lower and upper bounds of the finite element limit analysis method. The effects of the setback distance ratio (L/B), excavation height ratio (H/B), soil strength heterogeneity (kB/cu), and horizontal earthquake coefficient (kh) were analyzed. Design charts and tables were produced to clarify the relationship between the undrained seismic bearing capacity and the selected parameters.

关键词： excavation     finite element limit analysis     heterogeneous soil     strip footing     undrained bearing capacity    

HTML PDF 收藏

Influence of the Mechanical Seals on the Dynamic Performance of Rotor–Bearing Systems

XU Hua, ZHU Jun

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 96-100 doi: 10.1007/s11465-005-0008-5

摘要：

In this paper, to consider the effects of mechanical seals, a lumped-mass model and the transfer matrix method are used to establish the equations for the dynamics performance of rotor bearing system. The general inverted iteration method is also used to solve the eigenvalue problem of these equations. To check the response of the rotor bearing system under unbalance motivation, the Gauss method is used to calculate the dynamic response of the constrained vibration. The results, based on the dynamic properties calculation of a typical mechanical spiral seal, such as stiffness coefficients and damping coefficients, exert the influence of the mechanical seal on the rotor bearing system of the high-speed machinery. Meanwhile, some structure parameters that may affect the dynamic performance and forced vibration under unbalance motivation of the rotor bearing system considering mechanical seals are analyzed in the paper. The analysis results show that the mechanical seal more or less has effects on the rotor bearing system. The mechanical seal has much more effects on the flexible rotor bearing system than on the rigid one. For instance, in a certain case, if the effects of the mechanical seal were taken into account, the system s critical speed may increase by 70 80%.

HTML PDF 收藏

Ultimate bearing capacity of strip footing resting on clay soil mixed with tire-derived aggregates

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 1016-1024 doi: 10.1007/s11709-021-0751-7

摘要： This study investigated the use of recycled tire-derived aggregate (TDA) mixed with kaolin as a method of increasing the ultimate bearing capacity ( UBC) of a strip footing. Thirteen 1g physical modeling tests were prepared in a rigid box of 0.6 m × 0.9 m in plan and 0.6 m in height. During sample preparation, 0%, 20%, 40%, or 60% (by weight) of powdery, shredded, small-sized granular (G 1–4 mm) or large-sized granular (G 5–8 mm) TDA was mixed with the kaolin. A strip footing was then placed on the stabilized kaolin and was caused to fail under stress-controlled conditions to determine the UBC. A rigorous 3D finite element analysis was developed in Optum G-3 to determine the UBC values based on the experimental test results. The experimental results showed that, except for the 20% powdery TDA, the TDA showed an increase in the UBC of the strip footing. When kaolin mixed with 20% G (5–8 mm), the UBC showed a threefold increase over that for the unreinforced case. The test with 20% G (1–4 mm) recorded the highest subgrade modulus. It was observed that the UBC calculated using finite element modeling overestimated the experimental UBC by an average of 9%.

关键词： kaolin     physical modeling tests     stabilization     numerical modeling    

HTML PDF 收藏

Temperature control of transfer roller’s bearing based on finite element analysis

Peng ZHANG, Yourong LI, Han XIAO

《机械工程前沿（英文）》 2009年 第4卷 第2期   页码 215-218 doi: 10.1007/s11465-009-0026-9

摘要： After a heat preservation cover is installed on the main rolling line, the heat dissipation environment of the transfer roller working on the heat preservation cover is changed. To ensure the normal production, a reasonable working jet capacity of the roller neck is derived. First, a globe model of the transfer roller is built for finite element analysis. Second, the sub-model of the fixed end bearing is built and the boundary condition of the sub-model is supplied by the results of the globe model. The analysis result of the sub-model shows that the temperature of the transfer roller bearing exceeds 85°C a rolling periodicity later. With finite element analysis, the heat flux is obtained and the minimum working jet capacity is derived.

关键词： transfer roller bearing     finite element analysis     sub-model     temperature control    

HTML PDF 收藏

Liquefaction and impurity separation of oxygen-bearing coal-bed methane

Qiuying LI, Yonglin JU, Li WANG,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 319-325 doi: 10.1007/s11708-010-0115-9

摘要： Coal-bed methane (CBM) is a type of clean energy. However, most oxygen-bearing CBM have not yet to be utilized due to limited techniques, and when utilized, the discharged gas leads to resource wastage and environment pollution. In this paper, a liquefaction process is proposed and designed for the specified oxygen-bearing CBM obtained from the Daqing Qingshen gas field. The distillation column is employed to separate the oxygen and nitrogen components present in the CBM. HYSYS software is adopted to simulate the process, and the results reveal that the energy consumption of the whole liquefaction process is low. Moreover, oxygen and nitrogen are nearly removed completely, achieving a high-purity liquefied natural gas product with a high methane recovery rate. The applicability and safety of the liquefaction process are also analyzed. The simulation results can offer references for the separation of the oxygen component from CBM.

关键词： coal bed methane     oxygen-bearing     liquefaction     distillation    

HTML PDF 收藏

Effect of interface adhesion factor on the bearing capacity of strip footing placed on cohesive soil

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1494-1503 doi: 10.1007/s11709-021-0768-y

摘要： The problem related to bearing capacity of footing either on pure soil or on pure rock mass has been investigated over the years. Currently, no study deals with the bearing capacity of strip footing on a cohesive soil layer overlying rock mass. Therefore, by implementing the lower bound finite element limit analysis in conjunction with the second-order cone programming and the power cone programming, the ultimate bearing capacity of a strip footing located on a cohesive soil overlying rock mass is determined in this study. By considering the different values of interface adhesion factor (αcr) between the cohesive soil and rock mass, the ultimate bearing capacity of strip footing is expressed in terms of influence factor (If) for different values of cohesive soil layer cover ratio (Tcs/B). The failure of cohesive soil is modeled by using Mohr−Coulomb yield criterion, whereas Generalized Hoek−Brown yield criterion is utilized to model the rock mass at failure. The variations ofIf with different magnitudes of αcr are studied by considering the influence of the rock mass strength parameters of beneath rock mass layer. To examine stress distribution at different depths, failure patterns are also plotted.

关键词： bearing capacity     soil-rock interface     Hoek−Brown yield criterion     plasticity     limit analysis    

HTML PDF 收藏

标题 作者 时间 类型 操作

Air-bearing position optimization based on dynamic characteristics of ultra-precision linear stages

CHEN Xuedong, LI Zhixin

期刊论文

Model reduction techniques for dynamics analysis of ultra-precision linear stage

Xuedong CHEN, Zhixin LI

期刊论文

API-based assessment on urban air environment bearing capability in China

Jinnan WANG,Jing ZHANG,Hongqiang JIANG,Yaling LU

期刊论文

Electrorheological damper for the ultra-precision air bearing stage

ZHU Yu, JIA Songtao, CHEN Yaying, LI Guang

期刊论文

Air bearing center cross gap of neutron stress spectrometer sample table support system

Yang LI,Yunxin WU,Hai GONG,Xiaolei FENG

期刊论文

Iterative HOEO fusion strategy: a promising tool for enhancing bearing fault feature

期刊论文

New analysis model for rotor-bearing systems based on plate theory

Zhinan ZHANG, Mingdong ZHOU, Weimin DING, Huifang MA

期刊论文

The convexity about ultimate bearing hypersurfaces of structures

Chengxi GUO,Tingting GUO

期刊论文

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

期刊论文

Undrained seismic bearing capacity of strip footing adjacent to a heterogeneous excavation

期刊论文

Influence of the Mechanical Seals on the Dynamic Performance of Rotor–Bearing Systems

XU Hua, ZHU Jun

期刊论文

Ultimate bearing capacity of strip footing resting on clay soil mixed with tire-derived aggregates

期刊论文

Temperature control of transfer roller’s bearing based on finite element analysis

Peng ZHANG, Yourong LI, Han XIAO

期刊论文

Liquefaction and impurity separation of oxygen-bearing coal-bed methane

Qiuying LI, Yonglin JU, Li WANG,

期刊论文

Effect of interface adhesion factor on the bearing capacity of strip footing placed on cohesive soil

期刊论文