检索范围:
排序: 展示方式:
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
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
Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism
Jialun YANG, Feng GAO,
《机械工程前沿(英文)》 2009年 第4卷 第4期 页码 379-385 doi: 10.1007/s11465-009-0075-0
关键词: 2-DOF orthogonal spherical parallel mechanism singularity loci self-motions
Deformable image registration with geometric changes
Yu LIU,Bo ZHU
《信息与电子工程前沿(英文)》 2015年 第16卷 第10期 页码 829-837 doi: 10.1631/FITEE.1500045
关键词: Geometric changes Image registration Sparsity Traumatic brain injury (TBI)
Influence of kinematic redundancy on the singularity-free workspace of parallel kinematic machines
Jens KOTLARSKI, Bodo HEIMANN, Tobias ORTMAIER
《机械工程前沿(英文)》 2012年 第7卷 第2期 页码 120-134 doi: 10.1007/s11465-012-0321-8
In this paper the effect of kinematic redundancy in order to reduce the singularity loci of the direct kinematics and to increase the operational, i.e., singularity-free, workspace is demonstrated. The proposed approach consists of additional prismatic actuators allowing one or more base joints to move linearly. As a result, a selective reconfiguration can be performed in order to avoid singular configurations. Exemplarily, kinematically redundant schemes of four structures, the 3RRR, the 3RPR, the 6UPS, and the 6RUS, are considered. The relationship between the redundancy and the operational workspace is studied and several analysis examples demonstrate the effectiveness of the proposed concept. Furthermore, the additional benefit of an increasing number of redundant actuators is discussed.
关键词: parallel robots kinematic redundancy singularity avoidance operational workspace
Probabilistic analysis of secant piles with random geometric imperfections
《结构与土木工程前沿(英文)》 2021年 第15卷 第3期 页码 682-695 doi: 10.1007/s11709-021-0703-2
关键词: secant piles ultrasonic cross-hole testing probabilistic analysis reliability-based design random imperfections
《化学科学与工程前沿(英文)》 2022年 第16卷 第4期 页码 461-474 doi: 10.1007/s11705-021-2072-8
关键词: bimetal strategy oxygen vacancy non-noble metal catalyst hydrogenation aromatic nitro compounds
熊文成,申文明,王桥,史园莉,肖如林,付卓
《中国工程科学》 2014年 第16卷 第3期 页码 37-42
环境一号卫星A/B星是我国自主研制的小卫星星座,其在轨稳定运行近5年,并稳定获取了大量高质量的观测数据,实现对这些观测数据的几何精校正处理,对发挥环境星宏观、动态的生态环境监测有着重要意义。本文首先分析了环境一号卫星参数特点以及环境一号卫星2级数据(系统几何校正后的数据)的几何特点。基于此,设计了环境一号卫星各载荷总体几何精校正方法流程以及charge-coupleddevice(CCD)相机自动几何精校正方法。实际运行数据表明,该方法可以较好地实现环境一号卫星各载荷数据的自动几何精校正,环境一号卫星CCD相机自动几何精校正图像精度可达到2个像素以内,同星不同载荷图像之间自动匹配方法可以获取小于1个像素的图像匹配精度。
Isogeometric analysis based on geometric reconstruction models
《机械工程前沿(英文)》 2021年 第16卷 第4期 页码 782-797 doi: 10.1007/s11465-021-0648-0
关键词: isogeometric analysis reconstruction model level set function trimmed element point cloud
Guizhong XIE,Dehai ZHANG,Jianming ZHANG,Fannian MENG,Wenliao DU,Xiaoyu WEN
《机械工程前沿(英文)》 2016年 第11卷 第4期 页码 412-422 doi: 10.1007/s11465-016-0396-8
As a widely used numerical method, boundary element method (BEM) is efficient for computer aided engineering (CAE). However, boundary integrals with near singularity need to be calculated accurately and efficiently to implement BEM for CAE analysis on thin bodies successfully. In this paper, the distance in the denominator of the fundamental solution is first designed as an equivalent form using approximate expansion and the original sinh method can be revised into a new form considering the minimum distance and the approximate expansion. Second, the acquisition of the projection point by Newton-Raphson method is introduced. We acquire the nearest point between the source point and element edge by solving a cubic equation if the location of the projection point is outside the element, where boundary integrals with near singularity appear. Finally, the subtriangles of the local coordinate space are mapped into the integration space and the sinh method is applied in the integration space. The revised sinh method can be directly performed in the integration element. A verification test of our method is proposed. Results demonstrate that our method is effective for regularizing the boundary integrals with near singularity.
关键词: computer aided engineering (CAE) boundary element method (BEM) near singularity sinh method coordinate transformation integration space
Effects of critical geometric parameters on the optical performance of a conical cavity receiver
Hu XIAO, Yanping ZHANG, Cong YOU, Chongzhe ZOU, Quentin FALCOZ
《能源前沿(英文)》 2019年 第13卷 第4期 页码 673-683 doi: 10.1007/s11708-019-0630-2
关键词: parabolic collector conical cavity receiver critical geometric parameters optical performance
马景兰,王伟,万京生,张永丽
《中国工程科学》 2009年 第11卷 第8期 页码 93-96
低频振荡是影响电力系统稳定运行的一个重要方面。阐述了低频振荡产生的机理和分析方法,利用Hopf分歧理论,针对一个四阶模型的单机无穷大系统,分析了在临界点附近时可能出现的非线性奇异现象。研究表明:由于分歧的存在,导致系统稳定性在临界点附近出现奇异,从而影响了电力系统的稳定域。
Mechanical and geometric advantages in compliant mechanism optimization
Michael Yu WANG
《机械工程前沿(英文)》 2009年 第4卷 第3期 页码 229-241 doi: 10.1007/s11465-009-0066-1
关键词: compliant mechanisms topology optimization mechanical advantage pseudo rigid-body mechanisms
Alin STOICA, Doina PISLA, Szilaghyi ANDRAS, Bogdan GHERMAN, Bela-Zoltan GYURKA, Nicolae PLITEA
《机械工程前沿(英文)》 2013年 第8卷 第1期 页码 70-79 doi: 10.1007/s11465-013-0365-4
In the last ten years, due to development in robotic assisted surgery, the minimally invasive surgery has greatly changed. Until now, the vast majority of robots used in surgery, have serial structures. Due to the orientation parallel module, the structure is able to reduce the pressure exerted on the entrance point in the patient’s abdominal wall. The parallel robot can also handle both a laparoscope as well an active instrument for different surgical procedures. The advantage of this parallel structure is that the geometric model has been obtained through an analytical approach. The kinematic modelling of a new parallel architecture, the inverse and direct geometric model and the inverse and direct kinematic models for velocities and accelerations are being determined. The paper will demonstrate that with this parallel structure, one can obtain the necessary workspace required for a minimally invasive operation. The robot workspace was generated using the inverse geometric model. An in-depth study of different types of singularity is performed, allowing the development of safe control algorithms of the experimental model. Some kinematic simulation results and the experimental model of the robot are presented in the paper.
关键词: parallel robot minimally invasive surgery kinematics simulation
曹炳元
《中国工程科学》 2001年 第3卷 第3期 页码 52-55
变电所供电半径的选择是一个复杂的问题。为了确定最佳供电半径,减少投资,降低损耗,建立了Fuzzy环境下的变电所供电半径选择的几何规划模型。它包括软约束问题和含Fuzzy系数的问题。通过数值实例的计算,验证所建立的模型,与静态和动态的优化数学模型如控制模型和经典几何规划模型相比较,包含更多的信息,且获得了更满意的结果。
Chongzhe ZOU, Huayi FENG, Yanping ZHANG, Quentin FALCOZ, Cheng ZHANG, Wei GAO
《能源前沿(英文)》 2019年 第13卷 第2期 页码 284-295 doi: 10.1007/s11708-019-0613-3
关键词: cylindrical cavity receiver 3-D numerical simulation geometric optimization direct normal irradiation
标题 作者 时间 类型 操作
Finite element analysis of stress concentrations and failure criteria in composite plates with circular holes
null
期刊论文
Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism
Jialun YANG, Feng GAO,
期刊论文
Influence of kinematic redundancy on the singularity-free workspace of parallel kinematic machines
Jens KOTLARSKI, Bodo HEIMANN, Tobias ORTMAIER
期刊论文
Zinc modification of Ni-Ti as efficient NiZnTi catalysts with both geometric and electronic improvements
期刊论文
Implementation of sinh method in integration space for boundary integrals with near singularity in potential
Guizhong XIE,Dehai ZHANG,Jianming ZHANG,Fannian MENG,Wenliao DU,Xiaoyu WEN
期刊论文
Effects of critical geometric parameters on the optical performance of a conical cavity receiver
Hu XIAO, Yanping ZHANG, Cong YOU, Chongzhe ZOU, Quentin FALCOZ
期刊论文
Kinematic, workspace and singularity analysis of a new parallel robot used in minimally invasive surgery
Alin STOICA, Doina PISLA, Szilaghyi ANDRAS, Bogdan GHERMAN, Bela-Zoltan GYURKA, Nicolae PLITEA
期刊论文