检索结果-南通市图书馆

Enabling the transfer matrix method to model serial-parallel compliant mechanisms including curved flexure beams

在线全文

学校读者我要写书评

暂无评论

International Journal of Mechanical System Dynamics 2024年第1期4卷 48-62页

作者： Mingxiang Ling Lei Yuan Tingjun Zeng xianmin zhang Robotics and Microsystems Center Soochow UniversitySoochowChina Guangdong Key Laboratory of Precision Equipment and Manufacturing Technology School of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhouChina

Compliant mechanisms with curved flexure hinges/beams have potential advantages of small spaces,low stress levels,and flexible design parameters,which have attracted considerable attention in precision engineering,metamaterials,robotics,and so ***,serial-parallel configurations with curved flexure hinges/beams often lead to a complicated parametric ***,the transfer matrix method is enabled for analysis of both the kinetostatics and dynamics of general serial-parallel compliant mechanisms without deriving laborious formulas or combining other modeling ***,serial-parallel compliant mechanisms with curved flexure hinges/beams can be modeled in a straightforward manner based on a single transfer matrix of Timoshenko straight beams using a step-by-step *** and numerical validations on two customized XY nanopositioners comprised of straight and corrugated flexure units confirm the concise modeling process and high prediction accuracy of the presented *** conclusion,the present study provides an enhanced transfer matrix modeling approach to streamline the kinetostatic and dynamic analyses of general serial-parallel compliant mechanisms and beam structures,including curved flexure hinges and irregular-shaped rigid bodies.

关键词： compliant mechanisms curved flexure beams transfer matrix method nanopositioner rigid-body dynamics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

山区机场高填方边坡稳定性分析

力学与实践 2024年第1期46卷 89-98页

作者：冯兴姚仰平张健张献民黄信中国民航大学交通科学与工程学院天津300300 北京航空航天大学交通科学与工程学院北京100191

针对山区机场建设中的高填方边坡稳定性问题,本文解决了考虑含石量的统一硬化(unified hardening,UH)模型有限元强度折减法的关键问题:强度折减参数确定、安全稳定系数判断和初始地应力平衡方法确定。应用Mohr-Coulomb模型和考虑含石量... 详细信息

针对山区机场建设中的高填方边坡稳定性问题,本文解决了考虑含石量的统一硬化(unified hardening,UH)模型有限元强度折减法的关键问题:强度折减参数确定、安全稳定系数判断和初始地应力平衡方法确定。应用Mohr-Coulomb模型和考虑含石量的UH模型对山区机场高填方边坡稳定性进行了有限元分析,比较分析了应用两种模型计算的边坡安全稳定系数、位移和应变,得出了机场高填方边坡的稳定性规律,说明了应用考虑含石量的UH模型进行机场高填方边坡稳定性分析的有效性。

关键词：统一硬化模型土石混合料边坡稳定性强度折减法

自适应材料插值在柔顺常力机构非线性拓扑优化中的应用

在线全文

学校读者我要写书评

暂无评论

机电工程 2024年第5期41卷 913-923页

作者：梁俊文朱本亮张宪民华南理工大学机械与汽车工程学院广东广州510641

为解决柔顺常力机构的非线性拓扑优化中存在的数值不稳定问题,对非线性拓扑优化的材料插值方法进行了研究。首先,根据常力机构的工作特点以及输出特性,分别构建了其非线性拓扑优化的设计域以及优化模型;然后,对数值不稳定问题产生的原... 详细信息

为解决柔顺常力机构的非线性拓扑优化中存在的数值不稳定问题,对非线性拓扑优化的材料插值方法进行了研究。首先,根据常力机构的工作特点以及输出特性,分别构建了其非线性拓扑优化的设计域以及优化模型;然后,对数值不稳定问题产生的原因展开了讨论,从控制应变以避免数值不稳定问题的角度出发,提出了一种新的材料插值模型,模型中引入了参数α,对低密度单元抗变形能力进行了统一调节,并根据最大等效应变给出了一种参数α的自适应调整策略;最后,基于提出的材料插值模型,推导了常力机构优化模型的目标函数敏度表达式,对不同常力区间的常力机构进行了优化,分别对优化结果以及优化效率进行了讨论;并搭建了实验平台,对优化得到的常力机构的实际输出性能进行了验证。实验结果显示:该方法优化得到的常力机构在特定的常力区间内,最大输出力误差为2.3%。研究结果表明:自适应材料插值方法有效地避免了数值不稳定问题,稳定性得到了提升,且优化效率相比于附加超弹材料方法得到了提升。

关键词：柔顺常力机构自适应材料插值非线性拓扑优化数值不稳定目标函数敏度优化效率

Topology Optimization of Compliant Mechanisms with Geometrical Nonlinearities Using the Ground Structure Approach

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2011年第2期24卷 257-263页

作者： ZHAN Jinqing zhang xianmin School of Mechanical and Automotive Engineering South China University of Technology Guangzhou 510640 China

The majority of topology optimization of compliant mechanisms uses linear finite element models to find the structure *** the displacements of compliant mechanisms are intrinsically large,the topological design can not provide quantitatively accurate ***,topological design of these mechanisms considering geometrical nonlinearities is essential.A new methodology for geometrical nonlinear topology optimization of compliant mechanisms under displacement loading is *** elements are chosen to represent the design domain because they are capable of capturing the bending *** nonlinear structural response is obtained by using the co-rotational total Lagrange finite element formulation,and the equilibrium is solved by using the incremental scheme combined with Newton-Raphson *** multi-objective function is developed by the minimum strain energy and maximum geometric advantage to design the mechanism which meets both stiffness and flexibility requirements, *** adjoint method and the direct differentiation method are applied to obtain the sensitivities of the objective functions. The method of moving asymptotes（MMA） is employed as *** numerical example is simulated to show that the optimal mechanism based on geometrically nonlinear formulation not only has more flexibility and stiffness than that based on linear formulation,but also has better stress distribution than the *** is necessary to design compliant mechanisms using geometrically nonlinear topology *** with linear formulation,the formulation for geometrically nonlinear topology optimization of compliant mechanisms can give the compliant mechanism that has better mechanical performance.A new method is provided for topological design of large displacement compliant mechanisms.

关键词： compliant mechanisms topology optimization geometrical nonlinearities the ground structure approach displacement loading

基于投影寻踪模型的特高含水油藏剩余油可采潜力评价方法

在线全文

学校读者我要写书评

暂无评论

油气地质与采收率 2024年第1期31卷 137-144页

作者：刘晨冯其红何逸凡张先敏周文胜中国石油大学(华东)石油工程学院山东青岛266580 海洋石油高效开发国家重点实验室北京100028 中海油研究总院有限责任公司北京100028 中海石油(中国)有限公司天津分公司天津300459

影响特高含水油藏剩余油可采潜力的因素极其复杂,且各因素的影响程度差异明显,常规方法多以剩余油饱和度或剩余油储量丰度等单一指标评价剩余油潜力,难以有效指导特高含水油藏剩余油挖潜。在充分考虑特高含水油藏剩余油可采潜力影响因... 详细信息

影响特高含水油藏剩余油可采潜力的因素极其复杂,且各因素的影响程度差异明显,常规方法多以剩余油饱和度或剩余油储量丰度等单一指标评价剩余油潜力,难以有效指导特高含水油藏剩余油挖潜。在充分考虑特高含水油藏剩余油可采潜力影响因素的基础上,综合表征储层非均质性、剩余油可采储量规模、水淹状况以及油水分流能力的差异,构建了特高含水油藏剩余油可采潜力量化评价指标体系,并考虑不同指标对剩余油可采潜力控制程度的差异,将加速遗传算法与投影寻踪模型相结合来确定各评价指标的客观权重,从而构建了剩余油可采潜力指数,形成特高含水油藏剩余油可采潜力量化评价新方法。以渤海Q油田南区主力产层NmIL砂体为例,开展特高含水油藏剩余油可采潜力量化评价,结果表明,新方法可综合表征不同区域位置的储层物性、可采储量丰度和油水分流能力对剩余油可采潜力的影响,实现了主力产层NmIL砂体剩余油可采潜力分布的差异化定量评价,优势可采潜力区域刻画明显,将其作为NmIL砂体下一步井网加密调整潜力区域,以精准指导加密水平井的部署,为特高含水油藏剩余油挖潜提供了一种全新的分析方法与思路。

关键词：特高含水期剩余油可采潜力指数投影寻踪优势潜力丰度

维普期刊数据库博看期刊

The coalbed methane transport model and its application in the presence of matrix shrinkage

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第7期51卷 968-974页

作者： zhang xianmin TONG DengKe China University of Petroleum Dongying 257061China

Based on the theories of surface physical chemistry, theoretical formulations for permeability and porosity are presented which include both stress effect and matrix shrinkage in a single equation. Then, a three-dimensional, dual porosity, nonequilibrium adsorption, pseudosteady state mathematical model for gas and water is established and solved by the fully implicit method and the block precondition- ing orthomin algorithm. A history matching for the Qinshui Well TL003 is done. From the results, it is shown that the obvious enhancement of permeability occurs along with the passing time but the reservoir pressure of 15# coal seam cannot fulfill the critical adsorption pressure as a result of the water recharge of the aquifer. Hence, it is suggested to plug the 15# coal seam.

关键词： coalbed methane surface energy matrix shrinkage permeability numerical simulation

A level set method for reliability-based topology optimization of compliant mechanisms

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第4期51卷 443-455页

作者： zhang xianmin OUYANG GaoFei School of Mechanical Engineering South China University of TechnologyGuangzhou 510640China

Based on the level set model and the reliability theory, a numerical approach of reliability-based topology optimization for compliant mechanisms with multiple inputs and outputs is presented. A multi-objective topology optimal model of compliant mechanisms considering uncertainties of the loads, material properties, and member geometries is developed. The reliability analysis and topology optimization are integrated in the optimal iterative process. The reliabilities of the compliant mechanisms are evaluated by using the first order reliability method. Meanwhile, the problem of structural topology optimization is solved by the level set method which is flexible in handling complex topological changes and concise in describing the boundary shape of the mechanism. Numerical examples show the importance of considering the stochastic nature of the compliant mechanisms in the topology optimization process.

关键词： compliant mechanism reliability analysis topology optimization level set method

Design and Myoelectric Control of an Anthropomorphic Prosthetic Hand

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2017年第1期14卷 47-59页

作者： Nianfeng Wang Kunyi Lao xianmin zhang Guangdong Province Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology Guangzhou 510640 China

This paper presents an anthropomorphic prosthetic hand using flexure hinges, which is controlled by the surface electromyography （sEMG） signals from 2 electrodes only. The prosthetic hand has compact structure with 5 fingers and 4 Degree of Freedoms （DoFs） driven by 4 independent actuators. Helical springs are used as elastic joints and the joints of each finger are coupled by tendons. The myoelectric control system which can classify 8 prehensile hand gestures is built. Pattern recognition is employed where Mean Absolute Value （MAV）, Variance （VAR）, the fourth-order Autoregressive （AR） coefficient and Sample Entropy （SE） are chosen as the optimal feature set and Linear Discriminant Analysis （LDA） is utilized to reduce the dimension. A decision of hand gestures is generated by LDA classifier after the current projected feature set and the previous one are ＂pre-smoothed＂, and then the final decision is obtained when the current decision and previous decisions are ＂post-smoothed＂ from the decisions flow. The prosthetic hand can perform prehensile postures for activities of daily living and carry objects under the control of EMG signals.

关键词： electromyography anthropomorphic prosthetic hand myoelectric control pattern recognition prehensile gestures

Pseudo-rigid-body Model for Corrugated Cantilever Beam Used in Compliant Mechanisms

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第1期27卷 122-129页

作者： WANG Nianfeng LIANG Xiaohe zhang xianmin Guangdong Province Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University

Common compliant joints generally have limited range of motion, reduced fatigue life and high stress concentration. To overcome these shortcomings, periodically corrugated cantilever beam is applied to design compliant joints. Basic corrugated beam unit is modeled by using pseudo-rigid-body method. The trajectory and deformation behavior of periodically corrugated cantilever beam are estimated by the transformation of coordinate and superposition of the deformation of corrugated beam units. Finite element analysis（FEA） is carried out on corrugated cantilever beam to estimate the accuracy of the pseudo-rigid-body model. Results show that the kinetostatic behaviors obtained by this method, which has a relative error less than 6%, has good applicability and corrugated cantilever beam has the characteristics of a large range of motion and high mechanical strength. The corrugated cantilever beam is then applied to design a flexible rotational joint to obtain a larger angle output. The paper proposes a pseudo-rigid-body model for corrugated cantilever beam and designed a flexible rotational joint with large angle output.

关键词： corrugated beam pseudo rigid body method compliant mechanisms