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THEORY AND EXPERIMENT ON THE VISCOUS HEATING OF FLUID DAMPER UNDER SHOCK ENVIRONMENT 总被引:1,自引:0,他引:1
A specially designed fluid damper used as negative shock pulse generator in the shock resistance test system to dissipate the shock input energy in transient time duration is presented. The theoretical modeling based on the three-dimensional equation of heat transfer through a fluid element is created to predict the viscous heating in the fluid damper under shock conditions. A comprehensive experimental program that investigates the problem of viscous heating in the fluid damper under different shock conditions is conducted on the shock test machine to validate the analytical expression. Temperature histories for the fluid within the damper at two locations, the annular-oriflce and the-end-of stroke of the damper, are recorded. The experimental results show that the theoretical model can offer a very dependable prediction for the temperature histories in the damper for increasing input velocity. The theoretical model and experimental data both clearly indicate that the viscous heating in the damper is directly related to the maximum shock velocity input and the pressure between the two sides of the piston head. 相似文献
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具有粘性阻尼作用的粘弹性直杆的纵向振动 总被引:2,自引:0,他引:2
对具有粘性阻尼作用下的 Kelvin模型粘弹性杆的纵向振动问题 ,通过复数理论 ,将复特征方程化为两个联立的非线性特征方程组 ,分析了无量纲粘性阻尼系数、粘性阻尼作用位置及材料的无量纲松弛时间对一端固定一端自由的 Kelvin粘弹性杆复频率的影响。 相似文献
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根据磁性液体的磁粘特性,当磁性液体周围施加垂直于其涡旋矢量方向的磁场时,磁性液体的粘度增加,利用磁性液体作为减振器的阻尼液,通过改变磁场可以调节振动系统的阻尼比,从而达到减振的目的。根据这一特性,提出一种活塞式磁性液体减振器。根据磁性液体的流动方程和连续性方程,建立了减振器中磁性液体的动力学模型,并得到减振器阻尼力与振动速度之间的表达式以及减振系统的阻尼比。设计实验,将磁性液体减振器安装在悬臂梁自由端,利用线圈对减振器施加均匀磁场,研究不同线圈电流时磁性液体减振器对梁振动阻尼比的影响。实验表明,在所假设的条件下,实验结果与理论结果的一致性较好。同时得出,在一定范围内,活塞式磁性液体减振器的阻尼效果随着线圈电流的增大而增大。 相似文献
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在分析了影响电流变阻尼器的粘性阻尼和屈服阻尼的诸多因素后,提出利用多层电极结构来扩大阻尼器的可控范围。研制了一套可测试电流变阻尼器阻尼系数、响应时间和耗散功率的静特性测试系统。为了充分利用阻尼器的可控范围,对阻尼器与减振系统的匹配设计进行了研究。针对电流变阻尼器的阻尼力具有非线性的特点,提出了以平均阻尼匹配减振系统最佳被动阻尼的设计准则。最后利用电流变阻尼器对双层隔振系统,以正弦扫频信号作为激励,通过在线主导频率的识别,进行了自适应阻尼减振控制试验,结果表明共振频率和高频的振幅减振效果均达到30%以上。 相似文献
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Kalman Peleg 《International Journal of Mechanical Sciences》1979,21(2):75-84
Simple linear Kelvin or Maxwell models cannot predict adequately the response of many practical systems to vibration excitation. A more realistic model consisting of a mass between two preloaded non-linear (cubic elasticity springs) and restrained by a Coulomb and viscous damper is proposed. A harmonic motion solution, satisfying “on the average” the non-linear differential equation of motion of the model is developed whereby equations for frequency response curves are obtained. Expressions for relative and absolute transmissibility as well as their values at resonance are developed, these are shown to properly reduce to the respective exact expressions of a Kelvin model and friction damped linear spring. Although the model is intended mainly for quantitative design in packaging engineering problems, it is suitable for studying general vibration isolation problems as well. 相似文献
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挤压式磁流变液阻尼器--转子系统的动力学特性与控制 总被引:8,自引:3,他引:8
用磁流变液代替常规挤压油膜阻尼器的润滑油,可制成阻尼特性受磁场控制的挤压油膜阻尼器,用于转子系统的振动控制。依据Bingham模型推导了磁流变液挤压油膜的雷诺方程及其解的表达式,给出了油膜流速、压力分布、油膜反力和阻尼器内磁拉力等的计算公式;以磁流变液阻尼器—刚性转子系统为例,理论分析了挤压油膜的力学特性和转子系统的不平衡响应特性;设计和制造了一种用于转子振动控制的挤压式磁流变液阻尼器;试验研究了支承在该阻尼器上的单盘偏置柔性转子系统的不平衡响应特性和控制方法。研究表明,磁拉力可降低一阶临界转速和临界振幅;油膜反力可降低转子系统在无阻尼临界转速处的振幅,并使一阶有阻尼临界转速增大;通过开关控制能使阻尼器具有最佳的减振效果,使转子振幅在全转速区达到最小。 相似文献
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Free vibration analysis of a resilient impact damper 总被引:2,自引:0,他引:2
The free vibration of a vibratory system equipped with a resilient impact damper is studied. A simple model of impact damper is constructed using spring, mass and viscous damper. The important feature to be carried out in the analysis of this model is that the deformation of an impact damper during the collision with and the main mass can be formulated; therefore, the contact time is taken into consideration. This feature is important for a resilient rather than a rigid impact damper when the noise issue is concerned. The investigation showed that the effective reduction of the vibration response depends not on the number of impacts but primarily on the type of collision that the impact mass collides with the main mass face-to-face. Results also show that the clearance of an effective impact damper should be smaller than twice of the initial displacement of the main mass of the vibration system if the system is stimulated by an initial displacement only. Finally, an example of application of an impact damper on a cantilever beam is demonstrated. 相似文献
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对航天器或者雷达天线进行隔振是减少其受到振动载荷的有效方法.采用一种基于3-SPR并联机构的稳定平台进行主动隔振.建立上平台坐标系、下平台坐标系、全局坐标系,分析推导3个坐标系的姿态变换矩阵,将3-SPR并联机构作为稳定平台进行运动学和静力学特性分析,建立包含下平台和上平台同时运动的运动学公式及其静力平衡方程和静力传递... 相似文献
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为了提高船舶动力设备单层隔振系统的隔振性能,研究半主动磁流变(magnetorheological,简称MR)阻尼器和基础质量对系统传递特性的影响规律,采用通过试验验证的改进的Bingham模型描述MR阻尼器的力学特性,建立考虑基础质量影响的二自由度无约束隔振系统的动力学模型。通过平均法得到了隔振系统主共振时的解析解,并通过数值方法验证了理论解的正确性。以力传递率为评价指标,研究了半主动隔振系统主要参数对系统主共振的影响。结果表明:基础质量增加可降低系统的固有频率及隔振区域的减振效果;MR阻尼器控制力和零力速度的增加可提升隔振性能;MR阻尼器的阻尼增加可提高共振区域的隔振效果,但降低了隔振区域的隔振效果。 相似文献
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磁流变液阻尼器-柔性转子系统振动特性与控制的再研究 总被引:3,自引:0,他引:3
对先前提出的理论分析模型进行适当改进,用新模型对支承在磁流变液阻尼器上的单盘悬臂柔性转子系统的振动特性和控制技术进行再研究。研究表明,随着磁流变液阻尼器的库仑阻尼力的增大,系统在无阻尼临界转速处振幅明显下降,但在两阶临界转速之间的一定转速区振幅增加;同时,随着库仑阻尼力的增加,阻尼器轴承处的振幅在几乎所有转速时都被减小,甚至在某些转速区间该轴承被“锁住”,而且轴承能够振动的区间越来越窄。这说明转子系统从一个弹性支承系统逐步转化为一个准刚性支承系统,阻尼器支承的有效刚度越来越大,使得一阶有阻尼临界转速逐渐提高,并逐渐接近刚支临界转速。根据这些特性,提出通过开关控制抑止转子通过两阶临界转速过程中的振动,并使转子振幅在全转速区达到最小。仿真结果表明,系统能平稳通过两阶临界转速。 相似文献
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汽车悬架系统的半主动追踪控制 总被引:2,自引:0,他引:2
在介绍了磁流体减振器阻尼力特性的基础上,提出了针对磁流体减振器特性的半主动追踪控制方法。试验验证了磁流体减振器阻尼力可调的减振性能及追踪控制方法的有效性。结果表明提出的半主动追踪控制方法不仅比被动控制方式优越,而且比天棚式反向控制方式有更佳的减振效果。 相似文献
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金属丝网减振器在发动机隔振系统中的应用 总被引:3,自引:0,他引:3
AAW-400型金属丝网减振器是目前较为新型的隔振器,其中的金属网垫阻尼元件因为具有许多显著的优点而在隔振系统中得到了越来越广泛的应用.简要的说明了发动机工作时所引发的振动对车体及乘员的危害,分析了AAW-400金属丝网减振器的特点及其在发动机隔振系统中的应用. 相似文献
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In this paper, a small displacement-type magnetorheological grease (MRG) damper based on disk squeeze mode is proposed. The squeeze flow differential equation is obtained. The Navier slip condition is considered on the surfaces and the boundary compatible condition is established. The radial velocity profiles and the radial pressure distributions are derived respectively, and the mathematical stress expression is calculated. To verify rationality of analytical method, the MRG damper is designed and fabricated according to the technical requirements of an engine vibration isolation system. The experimental damping force from MTS870 Electro-hydraulic Servo with sine wave excitation shows that the proposed analytical method is feasible and provides the reference value for designing MRG damper based on disk squeeze mode. 相似文献
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采用半主动隔振系统可以有效衰减低频振动,降低振动物体的振动幅值.半主动减振器是半主动悬挂系统中的核心部件.根据流体力学理论和多体力学理论,按照半主动减振器的本构关系,建立了半主动减振器的仿真模型.通过数值仿真的方法研究了半主动减振器的出力特性,给出了半主动减振器的耗能曲线,并分析了影响半主动减振器性能的主要影响因素及其... 相似文献