Parametric identification of viscous damping models in the context of linear vibration theory is studied. Frequency domain identification methods based on measured frequency response functions (FRFs) are considered. Existing methods are classified into two main groups: matrix methods which use directly the measured FRF matrix, and modal methods which use modal parameters deduced from the FRFs. ...

(red arrows) and other places, the proposed method removes more offresonance artifacts than conventional autofocus and produces images comparable to field map-based correction. The estimated field map also exhibits better agreement with measurement except in featureless areas (white circle). Eq 1: fo(x,y) = fc + fxx + fyy Eq 2: so(kx,ky) = e–j2πfct s(kx+fxt,ky+fyt) Eq 3: s(0,0) = e+j2πfcTE so(–...

Vibration measurements of the linear accelerator structures in the SLC linac show a 1 micron rms vertical motion. This motion reduces to 0.2 micron rms motion when the cooling water to the accelerator structures is turned off. The quadrupoles have 250 nanometer rms vertical motion with the accelerator structure cooling water on and 60 nanometer motion with it off. These results together with me...

A method based on the power series solution is proposed to solve the natural frequency of flapping vibration for the rotating inclined Euler beam with constant angular velocity. The vibration of the rotating beam is measured from the position of the corresponding steady state axial deformation. In this paper the governing equations for linear vibration of a rotating Euler beam are derived by th...

This paper presents the design and evaluation of a novel permanent magnet (PM) energy harvesting system for scavenging electrical energy from ambient vibrations. A two-phase tubular linear PM vibration energy harvester consisting of a mover attached with permanent magnets and a slotted stator with built-in two-phase electromagnetic coils is proposed to convert vibrational kinetic energy into el...

In the area of fault detect for rotating machinery, the vibration signal should be filtered before parameter detection and quality evaluation. For the filtering of the vibration signal, it is needed to keep the linear phase characteristics while obtaining good filtering effect. Aiming at the filtering problem of vibration signal, a filtering algorithm based on singular value subspace decomposit...

A new self-powered magnetorheological (MR) damper control system was developed to mitigate cable vibration. The power source of the MR damper is directly harvested from vibration energy through a rotary permanent magnet direct current (DC) generator. The generator itself can also serve as an electromagnetic damper. The proposed smart passive system also incorporates a roller chain and sprocket,...

In this study, both theoretical linear model and numerical model are used to predict and optimize the frequencies of shimmy related modes and the level of the vibration for a vehicle. A theoretical multi-body linear model of 32-DOF were used for quasi-static analysis and modal analysis. The theoretical model was verified by comparing the results of modal analysis with those of modal test for fr...