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磁致伸缩主被动隔振装置中的磁机耦合效应研究 总被引:2,自引:1,他引:1
磁致伸缩材料和柔顺位移放大机构组成的主动驱动装置具有精度高、驱动力大等特点.将其与被动隔振装置并联,形成主被动隔振装置,可以弥补纯被动隔振在低频和微幅扰动工况下的不足.本文针对这类磁致伸缩主被动隔振装置进行磁机耦合效应研究.基于Jiles-Atherton模型,分析了磁致伸缩材料所受应力对有效磁场、磁化强度、磁致伸缩系数和材料杨氏模量的影响,表征了材料磁机耦合效应.在此基础上,建立了主被动隔振装置的动力学模型,分析了主动驱动装置与被动隔振装置间的耦合作用.在耦合作用影响下,若被动隔振装置刚度不同,即使输入磁场相同,驱动器产生的驱动位移和驱动力也不相同.磁致伸缩材料的变刚度效应使隔振装置整体等效刚度不再为定值,从而影响被动隔振效果.本文提出了通过柔顺机构参数设计减小前述两种耦合影响的方法.数值仿真结果表明,磁致伸缩主被动隔振装置在低于、接近和高于谐振频率三类扰动下,都能达到比被动隔振更好的振动抑制效果.此外,仿真结果验证了考虑磁机耦合效应的数值模型具有更高精度. 相似文献
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汽车发动机悬置是典型的6DOF动力隔振系统,传统的动力隔振模型将动力机械整体视为刚体,而本文考虑运动零部件的影响,为汽车发动机悬置的结构设计带来了一种全新的视角。通过对发动机上运动零部件进行受力分析,找到引起发动机振动的最主要内在激励源;建立6DOF动力隔振空间拓扑模型,利用Simscape/Multibody仿真研究,验证了传统的动力隔振模型与空间拓扑模型之间存在理论误差;动力隔振拓扑模型更能准确描述6DOF动力隔振系统特性,所建立的汽车6DOF发动机Simscape/Multibody仿真模型可为后续的主动悬置设计提供重要基础。 相似文献
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磁致伸缩材料和柔顺位移放大机构组成的主动驱动装置具有精度高、驱动力大等特点.将其与被动隔振装置并联,形成主被动隔振装置,可以弥补纯被动隔振在低频和微幅扰动工况下的不足.本文针对这类磁致伸缩主被动隔振装置进行磁机耦合效应研究.基于Jiles-Atherton模型,分析了磁致伸缩材料所受应力对有效磁场、磁化强度、磁致伸缩系数和材料杨氏模量的影响,表征了材料磁机耦合效应.在此基础上,建立了主被动隔振装置的动力学模型,分析了主动驱动装置与被动隔振装置间的耦合作用.在耦合作用影响下,若被动隔振装置刚度不同,即使输入磁场相同,驱动器产生的驱动位移和驱动力也不相同.磁致伸缩材料的变刚度效应使隔振装置整体等效刚度不再为定值,从而影响被动隔振效果.本文提出了通过柔顺机构参数设计减小前述两种耦合影响的方法.数值仿真结果表明,磁致伸缩主被动隔振装置在低于、接近和高于谐振频率三类扰动下,都能达到比被动隔振更好的振动抑制效果.此外,仿真结果验证了考虑磁机耦合效应的数值模型具有更高精度. 相似文献
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爆炸试验室基础隔振系统设计与应用 总被引:1,自引:0,他引:1
针对某爆炸试验室的基础隔振系统的改造,首先提出了一种由钢丝绳和碟形弹簧组合而成的新型隔振器,给出了相应的基础隔振方案,并对组合隔振器进行了试验研究。然后,采用两自由度、有阻尼计算模型对隔振系统的动力反应进行非线性分析,研究了隔振层刚度和阻尼对隔振系统动力反应的影响,优化选择了隔振系统的有关参数。研究结果表明,当隔振层刚度约为110 kN/mm,阻尼比为0.20~0.35时,隔振层动荷载接近最小,且其他动力反应满足设计要求。改造后的爆炸实验室的抗冲击能力比改造前提高了50%。 相似文献
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An improved constant volume cycle(CVC) model is developed to analyze the nozzle effects on the thrust and specific impulse of pulse detonation rocket engine(PDRE).Theoretically, this model shows that the thrust coefficient/specific impulse of PDRE is a function of the nozzle contraction/expansion ratio and the operating frequency. The relationship between the nozzle contraction ratio and the operation frequency is obtained by introducing the duty ratio, by which the key problem in the theoretical design can be solved. Therefore, the performance of PDRE can be accessed to guide the preliminary shape design of nozzle conveniently and quickly. The higher the operating frequency of PDRE is, the smaller the nozzle contraction ratio should be. Besides, the lower the ambient pressure is, the larger the expansion ratio of the nozzle should be. When the ambient pressure is 1.013 × 105 Pa, the optimal expansion ratio will be less than 2.26.When the ambient pressure is reduced to vacuum, the extremum of the optimal thrust coefficient is 2.236 9, and the extremum of the specific impulse is 321.01 s. The results of the improved model are verified by numerical simulation. 相似文献
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Aidin Delnavaz S. Nima Mahmoodi Nader Jalili Hassan Zohoor 《International Journal of Non》2010,45(2):176-185
Despite their simple structure and design, microcantilevers are receiving increased attention due to their unique sensing and actuation features in many MEMS and NEMS. Along this line, a non-linear distributed-parameters modeling of a microcantilever beam under the influence of a nanoparticle sample is studied in this paper. A long-range Van der Waals force model is utilized to describe the microcantilever-particle interaction along with an inextensibility condition for the microcantilever in order to derive the equations of motion in terms of only one generalized coordinate. Both of these considerations impose strong nonlinearities on the resultant integro-partial equations of motion. In order to provide an understanding of non-linear characteristics of combined microcantilever-particle system, a geometrical function is wisely chosen in such a way that natural frequency of the linear model exactly equates with that of non-linear model. It is shown that both approaches are reasonably comparable for the system considered here. Linear and non-linear equations of motion are then investigated extensively in both frequency and time domains. The simulation results demonstrate that the particle attraction region can be obtained through studying natural frequency of the system consisting of microcantilever and particle. The frequency analysis also proves that the influence of nonlinearities is amplified inside the particle attraction region through bending or shifting the frequency response curves. This is accompanied by sudden changes in the vibration amplitude estimated very closely by the non-linear model, while it cannot be predicted by the best linear model at all. 相似文献
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冲击波超压测试系统二次仪表频域特性 总被引:1,自引:0,他引:1
从二次仪表对冲击波的峰值、持续时间和比冲量3个主要参数的影响出发,首先构建了冲击波信号用以分析冲击波信号特性;搭建了适配器等效电路,对适配器的低频特性进行了实验研究;在MATLAB平台上构建了5种常用滤波器模型,模拟了不同类型滤波器和不同截止频率下测试系统的输出。模拟和实验结果表明:适配器的低频特性影响冲击波信号的持续时间和比冲量;在5种滤波器中贝塞尔滤波器最适合冲击波测试系统;滤波器截止频率对冲击波超压峰值影响明显;小型试验对测试系统的带宽要求高。 相似文献
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Dynamic flight stability of hovering model insects: theory versus simulation using equations of motion coupled with Navier–Stokes equations
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In the present paper, the longitudinal dynamic flight stability properties of two model insects are predicted by an approximate theory and computed by numerical sim- ulation. The theory is based on the averaged model (which assumes that the frequency of wingbeat is sufficiently higher than that of the body motion, so that the flapping wings' degrees of freedom relative to the body can be dropped and the wings can be replaced by wingbeat-cycle-average forces and moments); the simulation solves the complete equations of motion coupled with the Navier-Stokes equations. Comparison between the theory and the simulation provides a test to the validity of the assumptions in the theory. One of the insects is a model dronefly which has relatively high wingbeat frequency (164 Hz) and the other is a model hawkmoth which has relatively low wingbeat frequency (26 Hz). The results show that the averaged model is valid for the hawkmoth as well as for the dronefly. Since the wingbeat frequency of the hawkmoth is relatively low (the characteristic times of the natural modes of motion of the body divided by wingbeat period are relatively large) compared with many other insects, that the theory based on the averaged model is valid for the hawkmoth means that it could be valid for many insects. 相似文献
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对于具有区间参数的桁架结构的动力特性分析问题,提出了一种新的分析方法即区间因子法。利用区间因子法,结构材料物理参数、几何尺寸均可表达为其区间因子和确定性量的乘积,进而结构的固有频率和振型也可显式表达成区间因子们的函数。利用区间算法,推导出了结构固有频率和振型的上、下限与均值的计算表达式。通过算例,分析了结构参数的不确定性对结构动力特性的影响,并验证了本文模型和方法的合理性与可行性。本文方法的优点是能够反映结构某一参数的不确定性对结构动力特性的影响。 相似文献
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针对抛投式机器人弹射过程中存在的高过载问题,使用缓冲材料对机器人进行减过载处理。讨论了缓冲材料在高过载情况下的吸能特性,根据抛投式机器人缓冲保护壳的结构和缓冲材料的性质,建立了单自由度支座激励系统数学模型,并对其系统固有频率和放大系数进行了分析。利用弹射器内弹道加速度测量系统测量了弹射器的激励曲线和机器人在缓冲材料作用下的响应。实验结果表明,当缓冲系统的固有频率与弹射器的激励频率接近时,系统产生共振,机器人所受过载增加。通过调整缓冲系统的参数,改变其固有频率,使系统放大系数小于1,避免产生共振。
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