Abstract The use of integrally blisk is becoming popular because the advantages in aerodynamic efficiency and mass reduction. However, an blisk, lack contact interface leads to a low structural damping compared assembled bladed disk. One emerging technique for based on friction ring damper, which exploits interfaces at underneath In this paper, three different geometries dampers are investigate...

A damage detection method is developed for nonlinear systems using model updating. The method uses a nonlinear discrete model of the system and the form of the nonlinearities to create an augmented linear model of the system. A modal analysis technique that uses forcing that is known but not prescribed is then used to solve for the modal properties of the augmented linear system after the onset...

Heavily loaded, stressed power systems exhibit complex nonlinear dynamic behaviors which can not be analyzed and described accurately by conventional linear methods such as eigen-analysis. Normal form of vector fields, a well established mathematical method, and Modal Series technique, a relatively newly established approach have been used as tools to analyze, characterize and quantify some of ...

In this research, the modal parameters of a beam in free-free condition are extracted by performing different experiments in laboratory. For this purpose, two different techniques are employed. The first methodology is considered as a time domain method in Operational Modal Analysis. While the other one is frequency domain impact hammer test which is categorized as an Experimental Modal Analysi...

ll rights reserved. +3243669505. s), [email protected] (G. Kerschen), [email protected] (J.C. Golinval). Finite element model ̈ M x (t)+ Kx (t) + fnl {x (t)} = 0 0 2 4 6 8 10 −100 −50 0 50 100 Time (s) A cc . ( m /s 2 ) Numerical NNM computation Experimental NNM extraction NNM frequencies NNM modal curves Experimental response (time series) Fig. 1. Theoretical and experimental nonlinear m...

The field of Operational Modal Analysis (OMA) has recently become an emerging research interest. OMA, also known as Response-Only Modal Analysis, extracts the modal parameters by processing only the system response data. In many experimental measurement situations, the system’s output data series is short in length and buried under potentially correlated noise. In such cases, the separation of ...

double- unsymmetric-plan medium-rise buildings subjected to bi-directional seismic excitation are complex structures where higher-mode effects in plan and elevation are important in estimating the seismic responses using nonlinear static or pushover analysis. considering two horizontal components of the ground motions makes the problem more intricate. this paper presents a method for nonlinear ...

Initial-value and periodic nonlinear pulsation integrations are carried out for a series of doublemode Cepheid models (PdPo 0.7) in the vicinity of the resonance WI + Wo = W3. None of the models tested shows persistent double-mode behavior. A new, semiquantitative description of modal selection, based upon the iterative theory of Simon, is introduced to analyze the nonlinear results. In the sim...

Modal analysis of an optical field via generalized interferometry (GI) is a novel technique that treats said field as a linear superposition of transverse modes and recovers the amplitudes of modal weighting coefficients. We use phase retrieval by nonlinear optimization to recover the phase of these modal weighting coefficients. Information diversity increases the robustness of the algorithm by...

Estimation of the modal parameters of mechanical systems or structures is usually achieved by applying the well-known Frequency Response Function (FRF) method to experimental data obtained from free vibration after a shock excitation of the system or forced vibration using a variety of excitation signals. This method is however limited only to linear systems. The problem becomes more complex wh...