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Vibration Isolation for Noise Control
Published in Randall F. Barron, Industrial Noise Control and Acoustics, 2002
One of the important factors in design for vibration isolation is reduction of the force transmitted to the base or support of the system. Generally, the objective of vibration isolation is to reduce the transmitted force to an acceptable value. The force transmitted to the base is equal to the sum of the spring force and the damper force, as illustrated in Fig. 9-7: FT(t)=FS+Fd=KSy(t)+RMv(t)
Introduction to Vibrations
Published in Ramin S. Esfandiari, Bei Lu, Modeling and Analysis of Dynamic Systems, 2018
Vibrations are undesirable in many systems. The reduction of vibration can be achieved through vibration isolators or vibration absorbers. A vibration isolation system attempts either to protect delicate equipment from vibration transmitted to it from its support system or to prevent the vibratory force generated by a machine from being transmitted to its surroundings. The essence of these two objectives is the same. The concept of displacement transmissibility X/Z0 can be used for displacement isolation design, whereas force transmissibility FT/F0 can be used for force isolation design, where X/Z0 = FT/F0.
Machining Dynamics
Published in David A. Stephenson, John S. Agapiou, Metal Cutting Theory and Practice, 2018
David A. Stephenson, John S. Agapiou
Vibration isolation is the reduction of vibration transmission from one structure to another via some elastic device; it is an important and common component of vibration control. Vibration isolation materials, such as rubber compression pads, metal springs, and inertia blocks, may be used [6,163]. Rubber is useful in both shear and compression; it is generally used to prevent transmission of vibrations in the 5–50 Hz frequency range. Metal springs are used for low frequencies (>1.5 Hz). Inertia blocks add substantial mass to a system, reducing the mounted natural frequency of the system and unwanted rocking motions, and minimizing alignment errors through an increase in inherent stiffness.
Ultra-low frequency vibration control of urban rail transit: the general quasi-zero-stiffness vibration isolator
Published in Vehicle System Dynamics, 2022
Liuchong Wang, Yannan Zhao, Tao Sang, Haiyang Zhou, Ping Wang, Caiyou Zhao
The fourth-order Runge–Kutta method was utilised for time-domain numerical simulation according to the vibration isolator system analytical vibration differential equation. Figure 4 shows the vibration isolator time-domain response. When the mass block stabilised under a single frequency external force, the mass block maximum displacement was taken as the initial system displacement when the next excitation frequency was applied. The non-linear vibration system dynamic response was very sensitive to the initial value. As a result, when the excitation frequency was swept from low to high frequency (forward-sweeping frequency), the system frequency domain response was not consistent with the result when the excitation frequency swept from high to low frequency (reverse-sweeping frequency). The frequency range of the inconsistent responses of these forward and reverse sweeps was generally called the unstable region. To represent the vibration isolation system vibration isolation performance, the vibration force transmissibility rate (FTR) could be defined as: where was the stable maximum displacement and was the maximum velocity.
The vibration and pull-in mechanism of two coupled elastically restrained beams assembly subjected to electrostatic force
Published in Mechanics of Advanced Materials and Structures, 2020
Shueei-Muh Lin, Shu-Jhang Lee, Cheng-Che Lin
For the dynamic application, Oniszczuk [14] investigated the forced vibration of an elastically connected simply supported double-beam system. Gao and Cheng [15] investigated the active vibration isolation of a two beams assembly with a piezoelectric actuator. De Rosa and Lippiello [16] investigated the free vibration of double-beams by using the differential quadrature method. Sadek et al. [17] presented the computational method for solving optimal control of a system of parallel beams. Li and Hua [18] studied the vibration of an elastically damped connected three-beam system. One thing in common is linear behavior in these investigated systems. On the contrary, Lin [1] investigated the mechanism of the double-beams assembly subjected to the AC voltage. Samaali et al. [7] proposed the design of an ohmic contact RF microswitch with low voltage actuation. The proposed design consisted of two cantilevered microbeams; each one is attached to a rigid microplate (electrode) at its free end, and clamped to the substrate at the other end. Moreover, the experimental measurements found that the size-dependent effect on the torsion and bending of microns or sub-microns structures should be considered [19], [20]. Ghalambaz et al. [20] investigated the size effect on the pull-in instability of a nano-actuator. Beni [21] analyzed the size effect on the performance of a piezoelectric nanobeam.
Dynamic performance analysis of vehicle seats with embedded negative stiffness elements
Published in Vehicle System Dynamics, 2020
Georgios Papaioannou, Artemios Voutsinas, Dimitrios Koulocheris, Ioannis Antoniadis
KDamper is an novel concept of passive suspension proposed by Antoniadis et al. [30,31], based essentially on the ideal combination of appropriate stiffness elements, including a negative mechanism. The Kdamper concept is already implemented in a various technological applications, and in this work is going to be tested in a seat suspension. The reason is that the model can provide much better vibration isolation and damping at low frequencies than other tuned mass damper models (TMD). In comparison with them, the KDamper achieves greater isolation, without demanding heavier masses, as in the case of the TMD. Moreover, the KDamper replaces the need for high inertial forces of the added mass with the force of the negative stiffness mechanism. The replacement could offer many advantages in low-frequency spectrum. In addition, regarding the quasi-zero-stiffness mechanisms, KDamper overcomes their main drawback of requiring a reduction in the overall system stiffness, decreasing the load support capacity of the system.