共查询到20条相似文献，搜索用时 31 毫秒
1.
Willian M. Kuhnert Paulo J. Paupitz Gonçalves Diego F. Ledezma-Ramirez Michael J. Brennan 《Journal of The Franklin Institute》2021,358(1):1070-1086
Recently, a lot of attention has been given to a mechanical device known as the inerter. It is a mechanical component that can be compared to a capacitor with two ungrounded terminals in the mechanical-electrical systems analogy. In this paper, it is shown that although the concept of an inerter as a separate mechanical element is relatively new, there are several well-established vibration isolation systems that exhibit similar behavior to a simple lumped parameter system containing an inerter. Through a review of the literature, a link is established between the old and new ideas. Furthermore, a comparison between the systems is carried out using the quantities of mechanical impedance and displacement transmissibility. The advantages and disadvantages of using the inerter in vibration isolation are discussed, and a simple way of improving the high-frequency performance without severely degrading the low-frequency performance is described. 相似文献
2.
《Journal of The Franklin Institute》2019,356(14):7689-7703
This paper investigates the benefits of the inerter in improving vibration suppression of milling machine tools. The traditional method for repressing the cutting vibration of milling machines includes applying passive mechanical networks that consist of masses, dampers, and springs. However, because the mass element is not a genuine two-terminal network element, the achievable performance of the passive mechanical networks might be restricted. The inerter was invented to substitute the mass element and has been successfully applied to many mechanical systems, such as vehicles and buildings. This paper extends the application of the inerter to a milling machine and discusses the resulting vibration suppression improvements. We first built a model of the milling machine via experiments, followed by applying three basic suspension layouts to the model and illustrating how the inerter can help reduce system vibration. Lastly, we conducted experiments to verify the effectiveness of the inerter in improving the manufacturing performance of the milling machine. 相似文献
3.
Two types of passive devices, namely, negative stiffness damper (NSD) and inerter damper (ID), have been receiving growing interest in vibration isolation and suppression, because both can produce negative-slope force-displacement relationships that are similar to those associated with active control forces. Despite such a similarity, these two passive dampers possess obvious differences in their mechanical behaviors. This study aims to illustrate the similarity and difference between these two dampers in vibration isolation applications with respect to the H2 and H∞ performance. The comparative study indicates that both dampers can reduce the H∞ norm effectively; the negative stiffness devices can reduce the H2 norm as well, whereas the H2 norm cannot converge under the influence of inerter. This finding explains why a tuned-inerter damper, i.e., an inerter connected in series with a spring with proper frequency tuning, is more commonly adopted in vibration isolation. The pros and cons of both devices were further discussed. 相似文献
4.
Yi-Yuan Li Sara Ying Zhang Jason Zheng Jiang Simon Neild 《Journal of The Franklin Institute》2019,356(14):7836-7854
Vibration suppression capabilities of linear passive vibration absorbers, such as traditional tuned mass damper (TMD), and recently proposed inerter-based vibration absorbers, have been studied for multiple mechanical systems. In particular, significant performance advantages have been obtained with a specific device making use of both inerter and mass elements, namely the tuned mass damper inerter (TMDI). However, there are still countless mass-included inerter-based configurations that have not been studied, which can potentially provide more preferred dynamic properties. In this paper, an immittance-function-layout (IFL) is introduced, which can cover a large range of topological connection possibilities with both mass and inerter elements. With the recently proposed structural immittance format, a systematic approach is established to identify the most beneficial IFL type mass-included inerter-based configurations with pre-determined number of each element type. Vibration suppression performance with single-IFL type device and two parallel-connected IFLs (i.e. dual-IFL) type devices are investigated in this paper. Three optimal configurations are identified for mitigating the maximum inter-storey drift of an example 3-storey building model subjected to base excitation. With this 3-storey building model, results show that, for the optimum single-IFL configuration, the performance improvement is 7.3% compared with the optimum TMDI, and with identified beneficial dual-IFL configurations, up to 34.9% performance advantages are obtained. Furthermore, consistent performance gains are shown under real-life earthquake inputs and with a 10-storey building model using identified absorber configurations. 相似文献
5.
In this paper a novel type of frictionless mechanical inerter device is presented, where instead of gears, motion of the flywheel is achieved using living-hinges. The design is a type of pivoted flywheel inerter inspired in part by the Dynamic Anti-resonant Vibration Isolator (DAVI) concept, which was first developed in the 1960s. Unlike the DAVI, it will be shown that the pivoted flywheel inerter has the advantage of producing balanced forces. Furthermore the use of living-hinges eliminates the need for gears or other frictional elements in the inerter mechanism. To demonstrate the utility of the new concept, a bench-top experiment was performed using a small-scale living-hinge inerter manufactured using polypropylene hinges. By estimating the experimental system parameters, the transmissibility results from the experiment could be compared to a mathematical model. These results showed that the living-hinge inerter provided an isolation effect of at least three orders of magnitude in terms of the maximum amplitude reduction from the uncontrolled system compared to that with the inerter added. Although friction was eliminated, the living-hinges did introduce additional damping, and this was found to correspond to an increase in the equivalent damping ratio for the uncontrolled system of 1.2%. It is shown that the living-hinge inerter developed in this paper fits all of the essential conditions required to be a practical inerter device. Furthermore, as it operates without mechanical friction, or fluid flow, it represents a new paradigm in experimental inerter technology. 相似文献
6.
This study introduces a novel particle inerter system (PIS) designed for vibration mitigation of structures. The new system comprises an inerter subsystem, a spring, and a tuned particle element, where the spring is used for tuning the particle element and the inerter subsystem is set for energy absorption and dissipation. The structural performance and the vibration mitigation effect of the PIS are assessed in terms of displacement and acceleration responses. An optimal design method is developed for a PIS under a performance-oriented design framework. Following the criterion of lightweight control, the added mass of the PIS is minimized under the constraints of target displacement and acceleration responses. A parametric analysis is performed and the robustness of the PIS for seismic response mitigation is verified. Design cases are carried out for the illustration of the proposed design method. The results show that the structural displacement and acceleration responses can be reduced significantly with the help of a PIS. Compared with the particle tuned mass damper with the same parameters, both the energy absorption and dissipation effects of the PIS are increased and the relative displacement response of the container in the PIS is reduced by the inerter subsystem. Under the same performance target, the required physical mass of the container and particles in the PIS is minimized and is significantly smaller than that of the conventional particle tuned mass damper. 相似文献
7.
《Journal of The Franklin Institute》2019,356(14):7626-7649
This work studies the advantageous features of the fluid inerter device for optimised structural control of buildings. Experimental data are first presented to characterise the fluid inerter dynamics, and validate the simplified analytical formulations. Building on these observations, the device is modelled as an inerter in parallel with a nonlinear dashpot representing a power law damping term. The latter dissipative effects are mainly induced by the pressure drops occurring in helical channels due to the fluid viscosity and density. Then, novel passive vibration control schemes are implemented for the earthquake protection of base-isolated buildings by combining the fluid inerter with a tuned mass damper system. To account for the uncertain nature of the earthquake input, the base acceleration is modelled as a Kanai–Tajimi filtered stationary random process. The optimal fluid inerter parameters, namely inertance and damping, are identified numerically by minimising stochastic performance indices relevant to displacement, acceleration, and energy-based measures of the structural response. The nonlinear damping behaviour of the fluid inerter is fully incorporated in the optimal design procedure via the statistical linearisation technique. Nonlinear response history analysis under an ensemble of 44 natural earthquake ground motions is carried out to assess the seismic performance of the system. Since inertance and damping are coupled characteristics in a real fluid inerter, design guidelines are finally outlined to determine the actual geometrical and mechanical properties of the device to achieve targeted parameters resulting from the optimisation procedure. 相似文献
8.
[目的/意义]本文对交互记忆系统理论在管理信息系统领域的相关重要研究文献进行梳理与总结,为研究者提供思路和方向。[方法/过程]本文将研究问题归纳为交互记忆系统对团队绩效和知识整合的影响。交互记忆系统对团队绩效的影响可以分为对软件开发团队绩效、虚拟团队工作绩效、团队创新绩效、社交媒体中团队绩效的影响。交互记忆系统对知识整合的影响可以分为对知识共享、知识搜索、知识协作、知识网络、知识转化和知识管理的影响。[结果/结论]针对目前的研究的局限性,未来的研究可以在理论模型、任务类型、时间维度、研究对象、数据获取、研究方法、研究内容等方面取得进展。 相似文献
9.
面对复杂性、综合性和交融性的重大问题，单一学科的理论和方法往往难以进行全方位的深入探讨和系统建构，因而交叉科学研究日益成为解决人类发展重大难题不可或缺的研究范式。近年来，交叉科学研究日益得到各国政府和科技管理部门的高度关注，然而，什么是真正意义上的交叉科学？如何测度交叉科学？如何衡量交叉科学研究的影响力？本文从交叉科学的概念与内涵出发，围绕一系列交叉科学相关问题展开探讨，在明确交叉科学概念与内涵的基础上，进一步从学科多样性与凝聚性两个视角对交叉科学的测度指标进行了归纳，并从引文影响和社会影响两个角度分析了当前交叉科学的影响评价中面临的问题。以期能够深化对交叉科学的认知与理解，为我国交叉科学研究与实践提供一定的参考与启示。 相似文献
10.
在当今大数据的时代背景下, 数据已经成为各个科研领域不可缺少的元素之一, 而科学数据元数据是信息资源的核心。科学数据元数据的开放与共享是各个领域都急需面对的问题, 关乎国家的发展, 社会经济的进步, 关乎科技领域的深度。本文就大数据时代科学数据元数据的开放共享问题进行探究, 为我国科学数据元数据相关的工作提供进一步的参考。 相似文献
11.
运用Cite Space软件绘制2006年以来国内关于开放式创新文献的科学知识图谱,选取创新绩效、创新模式、创新能力、知识管理、自主创新五方面视角,综述与分析国内开放式创新的研究进展。国内开放式创新的研究视角集中于实证层面,以企业为研究对象,运用问卷调查、样本数据及结构方程建模等研究方法探讨开放式创新绩效的影响因素、创新模式的优劣以及创新能力培养等问题。知识图谱显示,商业模式、创新网络、创新风险等将是开放式创新研究的重点领域。 相似文献
12.
中俄能源合作是中俄全面战略协作伙伴关系的重要内容,是意义重大的地缘战略合作。自1996年中俄能源合作拉开序幕以来,虽几经波折,但也取得了较大进展,且随着中蒙俄经济走廊的规划实施,中俄能源合作迎来新机遇。基于此,本文回顾了中俄能源合作取得的进展,从供求关系、能源政策、国际劳动地域分工、比较优势、区域发展政策、国际地缘环境变迁等角度全面分析了中俄能源合作的内在契合因素和外部推动因素,指出中俄利益诉求的内在契合性是中俄开展能源合作的决定性因素,外部推动因素则加速了中俄能源合作的进程。虽目前中俄能源合作态势良好,但仍面临合作体制机制欠缺、国际地缘环境变迁等诸多挑战,在国际地缘环境日益复杂的新时期,中俄应增强互信,深化中俄能源的地缘战略合作;抓住中蒙俄经济走廊的政策契机,拓宽合作模式与合作领域;制定中俄能源战略长期合作规划,完善中俄能源合作机制;兼顾周边地区,创建区域性能源共同体。 相似文献
13.
14.
基于泛长三角4省市26个城市面板数据,通过系数法和超效率SBM模型等方法测算2009—2018年该区域科技进步贡献率、农业碳排放量和绿色全要素生产率,并利用自回归分析滞后模型(ARDL)分析三者之间的关系。研究发现:(1)科技进步在一定程度上对农业碳排放具有抑制效应,其中在长期视角下因受科技研发水平所处阶段、农民综合文化素养等多种因素影响效果并不显著,农业科技进步贡献率每增加1%则农业碳排放减少0.03%,但在短期视角下的抑制作用显著,且新技术在第一阶段的抑制作用更明显,在下年度略有反弹;(2)长期视角下农业绿色全要素生产率(GTFP)对农业绿色低碳转型发展积极作用明显,农业GTFP每增加1%则碳排放减少0.24%,而短期视角下的影响不显著,出于成本考虑等原因,短期视角下农业碳排放当期量会对未来3年碳排放产生影响。基于研究结论,提出大力发展有机农业,构建完善的农业环境监督管理体系,加大对低碳农业的关注和投入力度,加强区域间统筹协调力度,推动技术研发实现突破性进展等对策建议,为促进泛长三角地区科技进步和农业GTFP发挥积极作用,实现农业低碳发展提供参考。 相似文献
15.
Zhenghua Li Xieliu Yang Qi Zhang Wenguang Yang Hemin Zhang Lianqing Liu Wenfeng Liang 《Biomicrofluidics》2021,15(3)
The demand to understand the mechanical properties of cells from biomedical, bioengineering, and clinical diagnostic fields has given rise to a variety of research studies. In this context, how to use lab-on-a-chip devices to achieve accurate, high-throughput, and non-invasive acquisition of the mechanical properties of cells has become the focus of many studies. Accordingly, we present a comprehensive review of the development of the measurement of mechanical properties of cells using passive microfluidic mechanisms, including constriction channel-based, fluid-induced, and micropipette aspiration-based mechanisms. This review discusses how these mechanisms work to determine the mechanical properties of the cell as well as their advantages and disadvantages. A detailed discussion is also presented on a series of typical applications of these three mechanisms to measure the mechanical properties of cells. At the end of this article, the current challenges and future prospects of these mechanisms are demonstrated, which will help guide researchers who are interested to get into this area of research. Our conclusion is that these passive microfluidic mechanisms will offer more preferences for the development of lab-on-a-chip technologies and hold great potential for advancing biomedical and bioengineering research studies. 相似文献
16.
Environmental degradation has become one of the major obstacles to sustainable development and human well-being internationally. Scientific efforts are being made to understand the mechanism of environmental degradation and sustainability. Critical Zone (CZ) science and research on the multi-functional landscape are emerging fields in Earth science that can contribute to such scientific efforts. This paper reviews the progress, similarities and current status of these two scientific research fields, and identifies a number of opportunities for their synergistic integration through functional and multi-functional approaches, process-based monitoring, mechanistic analyses and dynamic modeling, global long-term and networked monitoring and systematic modeling supported by scaling and deep coupling. These approaches proposed in this paper have the potential to support sustainable human well-being by strengthening a functional orientation that consolidates multi-functional landscape research and CZ science. This is a key challenge for sustainable development and human well-being in the twenty-first century. 相似文献
17.
[目的/意义]近年来,量化评价与同行评议相结合的综合评价方法越来越得到认可和重视,"五计学"也为综合评价方法提供理论基础和方法指导。文章通过梳理计量与评价领域的研究进展既可以清晰领域内研究者的情况,还能明确计量与评价领域的研究热点以及计量学方法随着评价活动的细化而衍生的发展脉络。[方法/过程]运用可视化分析法、社会网络分析法和内容分析法从作者、机构、期刊、关键词等角度入手对国内近十年(2010—2020年)计量与评价领域的研究现状、发展趋势进行了梳理和综述。[结果/结论]研究结果发现其发展特点是:领域内作者稳定而长寿,科研合作以师生合作为主,期刊仍处于持续发展阶段,计量与评价领域研究互相渗透与促进,研究热点为网络计量、Altmetrics、文献计量、科学评价、学术影响力和同行评议,并且呈现出以下趋势:(1)研究领域多元化和研究对象细分化;(2)认识全面化和指标精确化;(3)评价体系融合化和方法多样化的发展趋势。 相似文献
18.
19.