Topic
Modal testing
About: Modal testing is a research topic. Over the lifetime, 4047 publications have been published within this topic receiving 64772 citations.
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TL;DR: In this paper, an active modal control technique is developed for pipes conveying fluid with a flow speed exceeding the critical one, where the Timoshenko beam theory is used to establish the system equation of motion.
15 citations
TL;DR: In this paper, the effect of bearing stiffness on the natural frequencies in various modes of a geared rotor system has been found out using solid elements in the ANSYS Workbench of a gear rotor system supported on ball bearings at the ends.
15 citations
TL;DR: The in situ vibration measurements show that the forcing function developed by the distributed Lorentz forces on the surface of the single-winding gradient coil results in predominantly beam-type bending mode patterns in the low frequency range.
Abstract: The objective of this paper is to find the relatively low-frequency (200–2,000 Hz) mode shapes of a single-winding gradient coil cylinder with intermediate wall thickness. The dynamic behavior of a gradient coil cylinder plays a crucial role in determining and controlling the vibroacoustic performance of magnetic resonance imaging (MRI) scanners. Modal analyses of the gradient coil cylinder were carried out under different boundary conditions to obtain the various mode shapes. Theoretical modes, predicted by using modified Love’s governing equations, and numerical modes simulated using a finite element method show close agreement with experimental modal results and reveal the mode shapes for both free-end and fixed-end boundary conditions. These results were further compared to in situ measurements of the mode shapes of the gradient coil cylinder insert during scanning in a 4 Tesla MRI. The general agreement among the analytical, numerical, and experimental mode shapes indicates that a linear combination of basic beam vibration and ring vibration patterns occupy the dynamic vibration modes in the low frequency range. The in situ vibration measurements show that the forcing function developed by the distributed Lorentz forces on the surface of the single-winding gradient coil results in predominantly beam-type bending mode patterns in the low frequency range.
15 citations
TL;DR: Results indicate that vibration testing can be utilised to assess the modal parameters of lumbar motion segments, and might eventually be used to study the mechanical properties of spinal motion segments in vivo.
15 citations
TL;DR: In this article, a finite element model (FEM) of the ST drive from Seagate is developed in ANSYS to investigate the shock response of the hard disk drive (HDD).
15 citations