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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    

Vibratory behaviors of Jeffcott system on cylindrical roller bearings

Hao WU, Jianwen WANG, Qi AN

《机械工程前沿(英文)》 2009年 第4卷 第3期   页码 305-309 doi: 10.1007/s11465-009-0036-7

摘要: A Jeffcott rotor system of cylindrical roller bearings is studied in detail. Its critical speed is calculated by a new calculation method with roller bearing stiffness and damping. The influences of bearing parameters, such as the roller length, rotor mass, distance between the bearings and the kinematics viscosity of oil on the system critical speed are numerically studied, and the influences of an oil film and damping on the critical speed are also studied. Regular curves of the relationship between the geometric parameters and the system critical speed are obtained. The results show that with increasing roller length and radial load, the critical speed increases; and with increasing rotor mass and the distance between the bearings and the kinematics viscosity, the critical speed decreases. This means that an oil film will decrease the critical rotational speed of the rotor system.

关键词: roller bearing     bearing-rotor system     design value     critical rotational speed    

圆锥滚子轴承振动的灰色模糊聚类分析

刘劲军,夏新涛,张立红

《中国工程科学》 2008年 第10卷 第7期   页码 112-117

摘要:

以30204型圆锥滚子轴承试验数据为基础,利用灰色模糊聚类分析方法对影响圆锥滚子轴承振动的 因素进行了综合分析,将圆锥滚子轴承各项参数按其对振动的影响分为三类:第一类对振动的影响最大,其 中包括滚子凸度、滚子直径偏差Dw 等参数;第二类对振动的影响较大,其中包括内滚道圆度,内滚道直线性 Li 等参数;第三类对振动的影响最小,其中包括内滚道波纹度,内滚道的角度偏差Δ2β 等参数。根据分类可 知,试验中圆锥滚子轴承的大部分参数都会对振动产生较大的影响。

关键词: 圆锥滚子轴承     振动     灰色模糊聚类分析    

Finite element modeling of counter-roller spinning for large-sized aluminum alloy cylindrical parts

Dawei ZHANG, Fan LI, Shuaipeng LI, Shengdun ZHAO

《机械工程前沿(英文)》 2019年 第14卷 第3期   页码 351-357 doi: 10.1007/s11465-019-0528-z

摘要: Counter-roller spinning (CRS), where the mandrel is replaced by rollers, is an effective means of manufacturing large-sized, thin-walled, cylindrical parts with more than 2500 mm diameter. CRS is very complex because of multi-axis rotation, multi-local loading along the circumference, and radial-axial compound deformation. Analytical or experimental methods cannot fully understand CRS. Meanwhile, numerical simulation is an adequate approach to investigate CRS with comprehensive understanding and a low cost. Thus, a finite element (FE) model of CRS was developed with the FORGE code via meshing technology, material modeling, determining the friction condition, and so on. The local fine mesh moving with the roller is one of highlights of the model. The developed 3D-FE model was validated through a CRS experiment by using a tubular blank with a 720 mm outer diameter. The developed 3D-FE model of CRS can provide a basis for parameter optimization, process control, die design, and so on. The data on force and energy predicted by the 3D-FE model can offer reasonable suggestions for determining the main mechanical parameters of CRS machines and selecting the motors. With the predicted data, an all-electric servo-drive system/machine with distributed power was designed in this work for CRS with four pairs of rollers to manufacture a large-sized, thin-walled, cylindrical part with 6000 mm diameter.

关键词: large-sized cylindrical part     counter-roller spinning     aluminum alloy     finite element method     distributed power    

On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate

Hui Ching FAN, Hong Sen YAN

《机械工程前沿(英文)》 2012年 第7卷 第1期   页码 5-15 doi: 10.1007/s11465-012-0310-y

摘要:

Without modifying the cam contour, a cam mechanism with a variable input speed trajectory offers an alternative solution to flexibly achieve kinematic and dynamic characteristics, and then decrease the follower’s residual vibration. Firstly, the speed trajectory of cam is derived by employing Bezier curve, and motion continuity conditions are investigated. Then the motion characteristics between the plate cam and its roller follower are derived. To analyze the residual vibration, a single degree of freedom dynamic model of the elastic cam-follower system is introduced. Based on the motion equation derived from the dynamic model, the residual vibration of the follower is yielded. The design procedure to improve the kinematic and dynamic motion characteristics is presented and two design examples with discussions are provided. Finally, the simulations of the kinematic and dynamic models by ADAMS are carried out and verified that the design models as well as the performances of the mechanism are feasible.

关键词: cam mechanism     variable input speed     kinematic design     dynamic design     optimal design    

Nonlinear dynamic behaviour of a cam mechanism with oscillating roller follower in presence of profile

Walha LASSAAD, Tounsi MOHAMED, Driss YASSINE, Chaari FAKHER, Fakhfakh TAHER, Haddar MOHAMED

《机械工程前沿(英文)》 2013年 第8卷 第2期   页码 127-136 doi: 10.1007/s11465-013-0254-x

摘要:

In this paper we investigate the nonlinear dynamic behaviour of a cam mechanism with oscillating roller follower in presence of defects. The nonlinear developed lumped-mass model includes eight degrees of freedom with two nonlinear hertzian contacts. The first one is located between cam and first roller while the second is between second roller and the sliding rod. The nonlinear dynamic behaviour is described by second order differential equations which are resolved by using the implicit Newmark algorithm combined with the Newton-Raphson iterative scheme. The influence of the cam profile error on the dynamic behaviour is also investigated.

关键词: cam     nonlinear behaviour     oscillating roller follower     profile error    

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    

基于混沌振动力学的压路机工程

龙运佳,杨勇,王聪玲

《中国工程科学》 2000年 第2卷 第9期   页码 76-79

摘要:

为将混沌振动力学的理论研究转化为压路机工程的新技术成果,研制了三种混沌振动压路机(0.75t,10t,14t),并进行了振动测试、数值仿真与压实试验,证明混沌振动压路机比普通振动压路机提高工效12.2%。其中,14t重型混沌振动压路机已用于我国西部高速公路开发。

关键词: 混沌     振动     压路机工程    

高碾压混凝土坝智能碾压理论研究

刘东海,李丙扬,崔博

《中国工程科学》 2011年 第13卷 第12期   页码 74-79

摘要:

给出了高碾压混凝土坝智能碾压的概念及实现过程,提出了大坝实时监控和智能反馈控制的原理;在实时分析压实指标的基础上,建立了大坝压实质量多元回归模型,进而提出了碾压混凝土坝压实度全仓面实时评价方法;实现了施工过程中碾压机工作性态的自适应调整,确保碾压机速度、激振力、碾压遍数和压实厚度等全过程达标,可有效保证碾压质量,提高施工效率,为碾压混凝土坝建设质量控制提供了一条新的途径。

关键词: 碾压混凝土坝     质量控制     智能碾压     实时监控     质量实时评估    

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    

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    

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    

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    

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    

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%.

标题 作者 时间 类型 操作

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

Peng ZHANG, Yourong LI, Han XIAO

期刊论文

Vibratory behaviors of Jeffcott system on cylindrical roller bearings

Hao WU, Jianwen WANG, Qi AN

期刊论文

圆锥滚子轴承振动的灰色模糊聚类分析

刘劲军,夏新涛,张立红

期刊论文

Finite element modeling of counter-roller spinning for large-sized aluminum alloy cylindrical parts

Dawei ZHANG, Fan LI, Shuaipeng LI, Shengdun ZHAO

期刊论文

On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate

Hui Ching FAN, Hong Sen YAN

期刊论文

Nonlinear dynamic behaviour of a cam mechanism with oscillating roller follower in presence of profile

Walha LASSAAD, Tounsi MOHAMED, Driss YASSINE, Chaari FAKHER, Fakhfakh TAHER, Haddar MOHAMED

期刊论文

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

期刊论文

基于混沌振动力学的压路机工程

龙运佳,杨勇,王聪玲

期刊论文

高碾压混凝土坝智能碾压理论研究

刘东海,李丙扬,崔博

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

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

Jinnan WANG,Jing ZHANG,Hongqiang JIANG,Yaling LU

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