The paper presents a method of modal parameter estimation based on RLS (Recursive Least Square) algorithm, and wavelet filtering. The wavelet filtering gives possibility to decoupling frequency components of signal response of structure. This operation can also reduce the order of the signal model estimated by RLS algorithm. An additional advantage of this method is the possibility of adapting ...

Based on the differential transformation method, a semi-analytical solution is developed for free vibration and modal stress analyses of variable thickness two-directional functionally graded circular plates with restrained edges, resting on elastic foundations. Variations of the material and geometry parameters are monitored by five distinct exponential functions. The presented non-dimensional...

In this paper, the forming principle, meshing features and tooth surface equation were introduced. And the modal parameters distribution of cylindrical gears with arcuate tooth trace was researched. The results show: 1. The modulus was the biggest impact factor for modal and natural frequency of cylindrical gears with arcuate tooth trace, then tooth width, and the radius of tooth line have the ...

In some qualification such as damage detection, a more detailed representation including mass, stiffness, and damping property matrices plays a more pivotal role than an equivalent state-space model. In practice, estimating the modal parameters of the dominant modes in the signal records is superior to directly identifying the mass, stiffness, and damping matrices. In this paper, a novel techni...

The vibration data obtained from ambient, drop-weight, and shaker excitation tests of the Z24 Bridge in Switzerland are analyzed to extract modal parameters such as natural frequencies, damping ratios, and mode shapes. System identification techniques including Frequency Domain Decomposition and Eigensystem Realization Algorithm are employed for the extraction of modal parameters and the statio...

this paper presents an overview of model updating and particularly its application for updating of frame model. in this article a mathematical model of the frame was produced with finite element method. the frame was subjected to hammer modal testing. then the results of the modal testing were compared with those predicted with the model. this comparison revealed discrepancies between these two...

The modal parameters of simple structures can be easily established by the use of PULSETM, the Multianalyzer System Type 3560. This application note describes how to measure the modal frequencies by inspection of frequency response functions, how to determine the modal damping with the aid of the frequency weighting function included in the analyzer, and how to establish the mode shapes by exam...

We develop an approach to reduce the governing equation of motion for the nonlinear vibration of a clamped laminated composite to the Duffing equation in a decoupled modal form. The method of weighted residuals enables such a reduction for laminates with clamped boundary conditions. Both rigidly clamped and loosely clamped boundary conditions are analyzed using this method. The reduction method...

Modal testing is a well established technique used to extract modal parameters such as natural frequencies, modal damping factors and vibration mode shapes from structures. Here, the technique is applied to a relatively new percussion instrument – the steelpan. The steelpan also referred to as the Caribbean steel drum or pan originated in Trinidad and Tobago during the Second World War. In this...

An easy-to-implement method to measure relevant elastic and damping properties of the constituents of a sandwich structure, possibly with a heterogeneous core, is proposed. The method makes use of a one-point dynamical measurement on a thick plate. The hysteretic model for each (possibly orthotropic) constituent is written generically as “E(1 + jη)” for all mechanical parameters. The estimation...