A finite element model was developed to simulate the vibratory stress relief after welding. Both resonant and nonresonant vibrations can relieve residual stresses in welded structures by creating plastic deformation around the weld area. For the non-resonant vibration, the stress reduction strongly depends on the vibration amplitude. For the resonant vibration, the vibration frequency is the ke...

Based on the issue of torsional vibration, this article analyzes the structure of the drive part of coaxial drive printing system, constructs its mathematic model, and explores the mechanism of generation of torsional vibration of press-that is the coupling of inherent frequency between input signal and machine drive system which leads to torsional vibration. In view of this, it adopts the clos...

Bearing failure is often attributed to be one of the major causes of breakdown in industrial rotating machines that operate at high and low speeds. This paper presents results of a comparative experimental study on the application of the ultrasound technique for condition monitoring of low speed rolling element bearings and conventional vibration measurements with seeded faults on inner-race de...

In this paper, we propose a dual-fiberoptic Fabry–Perot interferometer (FFPI) sensing system integrated with low-cost and low-coherence light-emitting diode (LED) as light source to detect dynamic vibration caused by acoustic waves cut-off frequency of 200 Hz. When the signals are applied, FFPI on Styrofoam sheet provides function partially transforming longitudinal energy transverse generates ...

In this article, the H∞ optimization design of a hybrid vibration absorber (HVA), including both passive and active elements, for the minimization of the resonant vibration amplitude of a single degree-of-freedom (SDOF) vibrating structure is derived by using the fixed-points theory. The optimum tuning parameters are the feedback gain, the tuning frequency, damping and mass ratios of the absorb...

In this paper, Empirical mode decomposition (EMD) and Hilbert vibration decomposition (HVD) are employed to process various different types of non-stationary and nonlinear vibration. The properties of these two methods are systematically analysis by comparing the efficacy in some numerically simulated signals. Meanwhile these two methods are used to analyze a Wenchuan earthquake strong ground m...

I recall someone once saying to me that “perception is reality.” But say this to scientists or engineers who need to take experimental data at midnight because their lab equipment is sensitive to even the minutest vibration and they may tell you otherwise. The reality is that imperceptible vibrations can and do impact sensitive experiments, and identifying the sources and selecting the proper e...

different methods for detecting broken bars in induction motors can be found in literature. many of these methods are based on evaluating special frequency magnitudes in machine signals spectrums. current, power, flux, etc are among these signals. frequencies related to broken rotor fault depend on slip. in industrial environment due to some phenomena - such as load oscillation, other faults an...

In recent years, the use of wireless sensor networks for vibration monitoring is emphasized, because of its capability to continuously monitor at hard-to-reach locations of complex machines. Low power consumption is one of the main requirements for the sensor nodes in continuous and long-term vibration monitoring. However, the power consumption of state-of-the-art wireless sensor nodes is signi...

The biodynamic responses to the human body give an understanding of why human responses to vibration (changes in health, comfort, and performance) vary with the frequency and direction of vibration. Studies have shown that biodynamic responses also vary with the magnitude of vibration and that the backrests of seats influence the transmission of vibration to the seated human body. There has bee...