The Effect of Stiffness and Loading Deviations in a Nonlinear Isolator Having Quasi Zero Stiffness and Geometrically Nonlinear Damping

2017-11-09
Static deflections due to static loadings limit the isolation performance of linear vibration isolation systems. Therefore, quasi-zero stiffness (QZS) mechanisms, i.e. nonlinear isolators with high static and low dynamic stiffness characteristic, are used to decrease the natural frequency of the isolation structure and improve the isolation performance of the system while having the same loading capacity. However, the resulting system is highly nonlinear and unstable solutions may as well occur. Although increasing the amount of linear viscous damping in the system reduces the nonlinearity, it has adverse effect on the isolation region. Geometrically nonlinear damping is effective when the response of the isolation system increases; hence, isolation region is unaffected. Combination of position depended nonlinear damping and QZS mechanism eliminates highly input depended response of QZS mechanism. In this study, a single degree of freedom system with a nonlinear isolator having QZS mechanism and geometrically nonlinear damping is considered. The nonlinear differential equations of motion of the isolation system are converted into a set of nonlinear algebraic equations by using harmonic balance method, which are solved by using Newton's method with arc-length continuation. Several case studies are performed and the effect of stiffness and loading deviations on the isolation performance is studied.

Suggestions

An improved quasi-zero stiffness vibration isolation system utilizing dry friction damping
Donmez, Ata; Ciğeroğlu, Ender; Özgen, Gökhan Osman (Springer Science and Business Media LLC, 2020-07-01)
Quasi-zero stiffness (QZS) isolators, a nonlinear vibration isolation technique, enhance the isolation performance, by lowering the natural frequencies of an isolation system while providing higher static load bearing capacity compared to similarly performing linear isolators. Despite its performance improvement, the challenge of implementing QZS isolation systems is due to their highly nonlinear stiffness characteristics as a result of cubic like behavior of stiffness elements used. Although increasing lin...
The effect of antisymmetric tensor unparticle mediation on the charged lepton electric dipole moment
Iltan, E. O. (IOP Publishing, 2011-10-01)
We study the contribution of antisymmetric tensor unparticle mediation to the charged lepton electric dipole moments and restrict the free parameters of the model by using the experimental upper bounds. We observe that the charged lepton electric dipole moments are strongly sensitive to the scaling dimension d(U) and the fundamental scales M(U) and Delta(U). The experimental current limits of electric dipole moments are reached for the small values of the scaling dimension d(U).
The Effect of Antenna Correlation in Single-Carrier Massive MIMO Transmission
Beigiparast, Nader; Güvensen, Gökhan Muzaffer; Ayanoglu, Ender (2018-07-20)
This work presents a single-carrier massive MIMO transmission system for the frequency selective Gaussian multi-user channel. It considers both cases of spatially uncorrelated and correlated channel and compares them in terms of the user sum-rate as well as the general performance. We consider a channel with M antennas at the base station which provides services for K single-antenna users. We develop a general expression for the achievable rate among users in the channel with a correlation among antennas at...
The Design of a high frequency pulse width modulation integrated circuit with external synchronization capability
Şahin, Osman Ulaş; Koçer, Fatih; Department of Electrical and Electronics Engineering (2017)
The Pulse Width Modulation (PWM) has been playing an active role in circuits and systems for many years. The PWM is an irreplaceable part of the switch-mode power supplies (SMPS) and the class D power amplifiers (PA). The high frequency PWM operation is the key for having more compact SMPSs and class D PAs since it provides size reduction of the passive components, which dominates the size and the cost of these circuits. The digital implementation of the high frequency PWM inherently suffers from the lack o...
The Effects of static aeroelasticity on the performance of two-dimensional converging diverging nozzles
Düzel, Ümran; Eyi, Sinan; Department of Aerospace Engineering (2014)
This thesis analyzes the effects of static aeroelasticity on the performance of two dimensional converging diverging nozzles. A Flow analysis is conducted on five different configurations of two dimensional converging-diverging nozzles. Computational study is validated with experimental data. Two of the configurations, which have the same throat area, throat radius, and convergence angle and total nozzle length, are selected as the baseline geometries. By modifying throat radius and keeping all other geomet...
Citation Formats
A. DÖNMEZ, E. Ciğeroğlu, and G. O. Özgen, “The Effect of Stiffness and Loading Deviations in a Nonlinear Isolator Having Quasi Zero Stiffness and Geometrically Nonlinear Damping,” 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37460.