In this paper, a novel method for linear normal mode identification based on Blind Source Separation (BSS) is introduced. Modal coordinates are considered as a specific case of sources that have certain time structure. This structure can be identified by many BSS algorithms. However, algorithms based on second order statistics are particularly suited for the linear normal mode identification. T...

The flexibility of the mechanical system is one of the factors of the bandwidth limitation. Especially, it is known that an out-of-phase vibration mode makes the closed loop unstable with the negative feedback of the positioning error. In this paper, a novel mode shaping method for in-phase design of flexible structures is proposed. From the relation between the modal analysis and the state-spa...

The vibration characteristics of piezoelectric hollow-disc transducers were investigated in this paper. It was assumed that the vibration modes were coupled in the axial and radial directions. Theoretically the differential equations of piezoelectric motions were derived in terms of the axial and radial displacements and the electric potential. Solutions of the boundary value problem yielded th...

High cycle fatigue (HCF) cracks generated by compressor blade vibrations are a common source of failure in gas turbine engines. Current methods for crack detection are costly, time consuming, and prone to errors. In-situ blade vibration detection would help operators avoid critical engine speeds, and help infer the presence of cracks via a change in the mode of a blade. Blade vibrations can be ...

Micro-cantilevers are frequently used as scanning probes and sensors in micro-electromechanical systems (MEMS). Usually micro-cantilever based sensors operate by detecting changes in cantilever vibration modes (e.g., bending or torsional vibration frequency) or surface stresses when a target analyte is adsorbed on the surface. The catalyst for chemical reactions (i.e., for a specific analyte) c...

Reliable measurements of ball mill load parameters and reorganization of the operating statuses are the key factors for saving energy and optimization control. Empirical mode decomposition (EMD) and partial least squares (PLS) are used to analyze shell vibration signal and monitor mill load parameters of ball mill. The shell vibration signal is decomposed into several intrinsic mode functions (...

Vibrothermography is a technique for finding cracks and delaminations through infrared imaging of vibration-induced heating. While vibrothermography has shown remarkable promise, it has been plagued by persistent questions about its reproducibility and reliability. Fundamentally, the crack heating is caused by the vibration, and therefore to understand the heating process we must first understa...

The finite element method is adopted to establish the dynamical models of blade, bladed disk and blades-diskshaft assemblies. Based on the analysis of mistuned structure and the dynamic characteristics of model in different levels, it gives the vibration mode distribution of different models. The research shows that the characteristics of the bladed disk and shaft have a huge difference, where ...

In this paper, the combination of RBF (Radial Basis Function) neural network and sliding mode control, which is used for vibration control, is examined. The approach is based on a sliding mode control methodology which drives the system towards a sliding surface by tuning the parameters of the controller using Gaussian radial basis function neural network. The input and output of RBF neural net...

Jerk-limited trajectories are a widespread solution for the trajectory planning of industrial machinestools or robots. It is known that jerk limitation can reduce vibrations and in some cases can totally suppress residual vibration induced by a lightly damped stationary mode. However, for systems with time-varying mode, which is classically the case for configuration dependent mode or load mass...