检索结果-内蒙古大学图书馆

Study on design method for dynamics of machine tools based on advanced process system

Paper Asia 2018年第4期COMPENDIUM VOL. 1卷 102-105页

作者： Zhu, Peihao Li, Xiang Lu, KaiJie Zheng, QingChun Liu, JingNa Ma, WenPeng Hu, YaHui Yu, YangBin Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China

Machining accuracy depends not only the manufacturing error, thermal deformation, elastic deformation and wear but also the vibration produced by it. Establishing the dynamics model provides the basis of dynamic analysis. The most common dynamic models of machine tool are finite element model, lumped parameter model, distributed mass model and parameters identification. Above methods are applied by using the methods of multi-body dynamics, finite element and the progress of technology. design is finite optimization based on dynamic analysis to get limited improvements for existing empirical design. It is not possible to design the machine tool as required to achieve the expected dynamic performance. In order to comply with precision machine tool’s development demand and the challenge of machine structure design, This paper presents physical and dynamic models considering Machine-Tool-Workpiece Process system to discusses the dynamic cutting process of the dynamic cutting load, driving and executing devices under the excitations of non-equilibrium inertial load. The dynamic of machine tool is mapped to the relative displacement of tool nose. © 2018, SHPMedia Sdn Bhd. All rights reserved.

关键词： Dynamic models

来源：评论

学校读者我要写书评

暂无评论

Comparison on Thermodynamic Performances between Basic and Regenerative Sub-Critical Organic Rankine Cycles Coupled with Low Grade Heat Source

引用

IOP Conference Series: Materials Science and Engineering 2019年第1期473卷

作者： Pengfei Yuan Chao Zhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control 300384 Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) Tianjin 300384 China

The coupling effects of low grade heat source on thermodynamic performances of both the basic and regenerative sub-critical Organic Rankine cycle (ORC) systems are investigated and compared. Turbine inlet pressure and turbine inlet temperature are treated as independent variables. The system exergy efficiency is selected as the thermodynamic performance criterion. The waste hot water with temperature range of 373.15K to 423.15K is selected as the low grade heat source. Optimization studies are carried out by using eight common organic working fluids to recover heat energy, and relevant operating conditions are obtained respectively. The results indicate that both hot fluid inlet temperature and the allowable minimum hot fluid outlet temperature influence the optimal working fluid, relevant turbine inlet condition and system exergy efficiency. Optimal system exergy efficiency increases monotonously with increasing of hot fluid temperature for both ORC systems above. In comparison to the basic cycle configuration, optimal system exergy efficiency for the regenerative system using the same working fluid is not changed if relevant turbine inlet vapor is saturated, but is significantly improved if relevant turbine inlet vapor is overheating. Besides, the optimal working fluid is dependent on the heat source temperature and specific cycle configuration.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Flow Mechanism of Cooling Effectiveness Improvement for the Cylindrical Film Cooling Hole with Contoured Craters

引用

IOP Conference Series: Materials Science and Engineering 2019年第1期473卷

作者： Linchao Bai Chao Zhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control 300384 Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) Tianjin 300384 China

In this paper, a typical cylindrical hole with contoured craters is investigated in terms of the downstream flow field by numerical method at blowing ratios of 0.5, 1 and 1.5. The flow field and the cooling effectiveness are analyzed using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. In comparison to the cylindrical hole, the cratered hole shows a wider coolant coverage in lateral direction and a lower penetration into the mainstream flow due to the larger hole exit area. Moreover, the interaction between the coolant and the curved protrusion induces a new anti-kidney-shaped vortex pair, which can obviously improve the cooling coverage and thus the cooling effectiveness. The area-averaged cooling effectiveness for the cratered hole is always higher than that for the cylindrical hole at all three blowing ratios.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Theoretical prediction and experimental testing of mechanical properties for 3d printed silk fibroin-type II collagen scaffolds for cartilage regeneration

引用

MCB Molecular and Cellular Biomechanics 2018年第2期15卷 85-98页

作者： Gao, Lilan Yuan, Qingxian Li, Ruixin Chen, Lei Zhang, Chunqiu Zhang, Xizheng Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin30000 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300000 China Hospital of Stomatolgy NanKai University Tianjin300000 China

Silk fibroin-type II collagen scaffold was made by 3D printing technique and freeze-drying method, and its mechanical properties were studied by experiments and theoretical prediction. The results show that the three-dimensional silk fibroin-typeII collagen scaffold has good porosity and water absorption, which is (89.3%+3.26%) and (824.09%+93.05%), respectively. With the given strain value, the stress of scaffold decreases rapidly firstly and then tends to be stable during the stress relaxation. Both initial and instantaneous stresses increase with increase of applied strain value. The creep strains of scaffold with different stress levels show the two stages: the rapidly increasing stage and the second stable stage. It is noted that the scaffold with compressive stress of less than 35 kPa can recover when the compressive stress is removed. However when the compressive stress is higher than 50 kPa, the scaffold is damaged and its structure is destroyed. Not only the compressive property but tensile property of scaffold are dependent on the applied displacement rate or strain rate. Its compressive elastic modulus and tensile modulus increase with increase of strain rate or displacement rate. The nonlinear relaxation model and creep model were constructed respectively and applied to predict the stress relaxation behavior and creep behavior of scaffold. It is found that there are good agreements between the experimental data and predictions, which mean that the built theoretical model can predict the mechanical behavior of scaffold. Copyright © 2018 Tech Science Press.

关键词： Strain rate

来源：评论

学校读者我要写书评

暂无评论

Influence of Micro-texture Parameters on Bone Drilling Force and Torque: A Finite Element Model

引用

IOP Conference Series: Materials Science and Engineering 2019年第1期470卷

作者： Yahui Hu Xiangjun Li Chuncheng Chen Lili Su Qingchun Zheng Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin 300384 China Tianjin University of Technology 391 Binshui West Road Xiqing District Tianjin 300384 China.

The micro-texture on the tool surface is an effective way to improve the quality of the drilling. While high-performance micro-texture plays an important role in improving the quality of working surface and prolonging the life of tool. In this study, a three-dimensional finite element model was established to study the relationship between drilling thrust, torque and microstructure parameters (micro-pit depth, micro-pit diameter and micro-pit spacing) during drilling of cortical bone. The model was validated by cortical bone drilling using a micro-structured tool. On basis of this, the thrust and torque prediction models of the micro-texture parameters were obtained. The results indicate that the thrust and torque increased with the increase of micro-pit diameter; while the increase of the micro-pit spacing caused the thrust and torque to decrease. When the depth of the micro-pit increased, the thrust and torque decreased first and then increased, and we found that the effect of micro-pit spacing and micro-pit depth on force and torque is insignificant.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Author Correction: Effects of Precipitates Evolution on Low Stress Creep Properties in P92 Heat-resistant Steel

引用

Scientific reports 2019年第1期9卷 9567页

作者： Hongguang Han Junjie Shen Jiaxing Xie Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin 300384 China. National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin 300384 China. Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin 300384 China. 58920151@***. National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin 300384 China. 58920151@***.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Near-Optimal Online Motion Planning of Connected and Automated Vehicles at a Signal-Free and Lane-Free Intersection

Near-Optimal Online Motion Planning of Connected and Automat...

引用

2018 IEEE intelligent Vehicles Symposium, IV 2018

作者： Li, Bai Zhang, Youmin Zhang, Yue Jia, Ning Ge, Yuming Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing Xi'An University of Technology Xi'an710048 China College of Control Science and Engineering Zhejiang University Hangzhou310027 China Department of Mechanical Industrial and Aerospace Engineering Concordia Institute of Aerospace Design and Innovation Concordia University Montreal Canada Division of Systems Engineering Center for Information and Systems Engineering Boston University BostonMA02215 United States Institute of Systems Engineering Tianjin University Tianjin300072 China China Academy of Information and Communications Technology Beijing100191 China

ISBN: (纸本)9781538644522

In this paper, we propose a cooperative motion planning method for a group of connected and automated vehicles (CAVs) crossing a lane-free intersection without using explicit traffic signaling. This multi-vehicle motion planning task is formulated as a centralized optimal control problem. However, the solution to this optimal control problem is numerically intractable due to the high dimensionality of the collision-avoidance constraints and the nonlinearity of the vehicle kinematics. A two-stage strategy is proposed for generating online solutions: at Stage 1, the CAVs are requested to reach a standard formation before entering the intersection;at Stage 2, the vehicles cross the intersection. As the motion planning sub-problem at Stage 2 begins with a standard configuration, the optimal solution to this standard sub-problem can be computed offline in advance and applied online directly. On the other hand, the formation reconfiguration sub-problem at Stage 1 is easy to solve online. Through dividing the entire dynamic process into two periods, the difficulties in the original optimal control problem are significantly reduced so that the real-time performance is achieved. © 2018 IEEE.

关键词： Motion planning

来源：评论

学校读者我要写书评

暂无评论

Dynamic Analysis of a New Type of Asymmetrical Parallel Mechanism Based on Lagrange Method

引用

IOP Conference Series: Materials Science and Engineering 2018年第1期428卷

作者： Quan Li Bin Li Xinhua Zhao Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin 300191 China

In this article, a novel over constrained 2-RRU&RSR parallel manipulator is proposed and analyzed. This mechanism is composed of a moving platform and a base, which connected by two same configuration RRU legs and one RSR leg. The article uses the 2RRU&RSR parallel mechanism that can achieve 2R1T (two rotations and one translational motion) as the object. Based on the known kinematics forward solutions, the dynamics study was carried out. The dynamic model of the parallel mechanism was established using the Lagrange method and then it can be obtained that the dynamic inverse solution. Then ADAMS software was used to build a virtual prototype of this mechanism and the dynamics simulation was performed by using Lagrange method. Under the trend of a certain trajectory, the law of driving torque changes with time, paving the way for subsequent trajectory planning and control.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Ionic liquid choline chloride-urea dissolving cattle bone extracted hydroxyapatite

引用

Journal of Bionanoscience 2018年第3期12卷 437-441页

作者： Song, Wei Yang, Yan Deng, Yu Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China Department of Osteo-Internal Medicine Tianjin Hospital Tianjin300211 China School of Materials Science and Chemical Engineering Tianjin University of Science and Technology Tianjin300457 China

The dissolving technique of ionic liquid (IL) was applied in extraction process of hydroxyapatite (HAp). Product HAp was extracted by IL choline chloride-urea (ChCl-Urea) dissolving cattle bone. The optimum conditions for regeneration process of cattle bone were determined by single factor, orthogonal and verification experiments. IR spectra of regenerated bone, undissolved bone and raw bone showed that the main groups of regenerated bone did not change. It was indicated that ionic liquid did not damage the bone collagen of raw bone, and the collagen was only dissolved by IL. IR spectrum of the product HAp revealed that its components were similar to those of the natural bone. SEM pattern showed that the crystal shape of the product HAp appeared rod-like shape mostly, and the crystal structure was relatively complete. XRD diffraction explained that there was no difference between product HAp and standard HAp for the crystalline form and compositions. Copyright © 2018 American Scientific Publishers All rights reserved.

关键词： Hydroxyapatite

来源：评论

学校读者我要写书评

暂无评论

Distribution system state estimation considering the uncertainty of DG output

Distribution system state estimation considering the uncerta...

引用

2017 IEEE Conference on Energy Internet and Energy system Integration, EI2 2017

作者： Liu, Qian Ding, Lei Wang, Xiaohui Gao, Yadong Jin, Fei Wu, Jinyu Liu, Xiaoliang Key Laboratory of Power System Intelligent Dispatch and Control Ministry of Education Shandong University Jinan China Zhejiang Huayun Electric Power Engineering Design and Consulting Co. Ltd Hangzhou China Weifang Power Supply Company State Grid Shandong Electrical Power Company Weifang China

ISBN: (纸本)9781538614273

The penetration of DGs in modern distribution system brings more uncertainty. GMM (Gaussian Mixture Model) provides an effective way to represent the output distribution of DGs. The current used state estimator is based on WLS method which assumes the error information is Gaussian distributed. To successfully conduct the WLS based state estimation with GMM output, weights information of all the measurements is required. An effective approach to set reasonable weights for the measurements information is proposed in this paper with the purpose to improve the estimation quality with scarce real-time measurements. A simulation is conducted with ukgds-95 system with matlab software to validate the proposed method. © 2017 IEEE.

关键词： State estimation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：