An analytical method is proposed to get the amplitude-frequency and the phase-frequency characteristics of free/forced oscillators with nonlinear restoring force. The nonlinear restoring force is expressed as a spring with varying stiffness that depends on the vibration amplitude. That is, for stationary vibration, the restoring force linearly depends on the displacement, but the stiffness of t...

This work studies the dynamics of a 3D dimer bouncing upon a horizontal plate undergoing a vertical harmonic vibration. Despite complex interactions within the system due to impacts and friction, numerical simulation shows that, under certain conditions prescribed for the dynamics, the center of mass of the dimer, when projected onto a horizontal plane, will follow a circular orbit. The phenome...

Diesel engines have been widely used in various engineering applications. The performance of diesel engines is influenced greatly by the operation condition of the cylinder liner-piston ring. It is therefore crucial to investigate and assess the working condition of the cylinder liner-piston ring. Literature review indicated that there are few studies on this issue. Therefore, this study propos...

In this paper, a simple piezoelectric floating mass transducer (PFMT) for implantable middle ear hearing devices (IMEHDs) is proposed and its modeling and designing are studied. The transducer which can be implanted in the meddle ear consists of a PMN-PT multi-layered piezoelectric actuator, an elastic material, and a metal case. The proposed transducer has a simple structure and the force gene...

During production of glottal stops the glottal vibration has unequal cycles and is caused by laryngealization. While one can perceive the features of laryngealization in the speech, it is difficult to analyse the signal to detect these source features from the standard spectrum-based analysis methods. In this paper we propose methods to extract the voice source vibration characteristics, and sh...

Dynamic characteristics of a typical multistory building in Iran have been studied in two different stages of building construction, using ambient vibration tests. Finite element models have also been used to determine these characteristics and to verify test results. The results indicated the agreements and also differences between conventional theoretical models and the behaviour of real stru...

Vibration-based structure health monitoring technique detects the damage by observing the change in dynamic characteristics of the structure. Change in dynamic characteristics due to operational and environmental variation may confuse with the change due to damage in the structure resulting false alarm of the damage. In SHM, data normalization technique can be used to suppress the adverse effec...

Research shows that multi-fractal can not only exhibit the singular probability distribution form of the fractal signal completely, but also increase the fine level of signal geometrical characteristics and local scaling behavior. Based on multi fractal dimension calculation of time-frequency matrix of vibration signal of rolling bearing in this paper, energy distribution characteristics of tim...

Cascade-Correlation (CC) network is a new architecture and supervised learning algorithm for artificial neural networks. The learning algorithm of CC network and its network structure are described in this paper, the CC network with an excellent fitting ability is applied to fitting vibration characteristics of hydraulic turbine units according to different parts under three water heads. Compar...

This paper puts forward a robust change detection procedure able to analyze the transient seismic motion and the vibration structure response, as well as to determine the changes in the amplitude and frequency content of the structure. This technique makes use of an impulse invariant transformation that will enable us to obtain an equivalent model of the vibration structure, represented by a pa...