in this paper, a structural damage identification method (sdim) is developed for plate-like structures. this method is derived using dynamic equation of undamaged/damaged plate, in which local change in flexural rigidity is characterized utilizing a damage distribution function. the sdim requires to modal data in the intact state and frequency response of damage state where most of vibration ba...

the paper investigates into the vibrational characteristics of the truck chassis including the natural frequencies and mode shapes. truck chassis forms the structural backbone of a commercial vehicle. when the truck travels along the road, the truck chassis is excited by dynamic forces caused by the road roughness, engine, transmission and more. modal analysis using finite element method (fem) ...

The various types of metamaterials only have a sound transmission loss (STL) peak at the resonant frequency but are still constrained by law mass insulation other frequencies. In this paper, low-frequency and wideband metamaterial plate with front radial membrane was designed in order to improve noise reduction band. Bandgap STL were calculated using finite element method. Studies shown that ra...

In the present article, buckling analysis of functionally graded annular thin and moderately thick plates under mechanical and thermal loads is investigated. The equilibrium and stability equations of the plate are obtained based on both classical and first order shear deformation plate theories. By using an analytical method, the coupled stability equations are converted to independent equatio...

The wide application of switched reluctance motors (SRM) is limited by their higher vibration and acoustic noise. An accurate determination of resonant frequencies and mode shapes of the SRM stator is therefore essential for low acoustic noise design. Based on the structural finite element method and elasticity theory, 3D vibration modes and resonant frequencies of a 5 hp SRM with 8/6 poles are...

This paper represents the first effort in seismic fragility analysis of a structure using a structural analysis model developed on the basis of measured vibration data. An instrumented highway bridge is used to demonstrate the analysis procedure involving measuring ambient vibration, identifying modal parameters from the measured data, updating a preliminary FE model (obtained from structural d...

We describe a far-infrared electron-paramagnetic-resonance ~EPR! spectrometer for broadband ~100–300 GHz! use. The spectrometer is operated in the reflection mode and uses broadband quasioptical methods to separate the transmitted from the reflected radiation. We describe and illustrate its operation at 170 GHz ~1.8 mm! and compare its performance to that of our transmission mode spectrometer o...

In this paper, the equations of structural motion are expressed in time-invariant state-space equations by expressing the frequency dependent self-excited forces in terms of rational functions. Accordingly, the multimode coupled flutter analysis is reduced to evaluate the eigenvalues of a constant matrix at each prescribed wind velocity. This formulation is computationally efficient in comparis...

Feathers can produce sound by fluttering in airflow. This flutter is hypothesized to be aeroelastic, arising from the coupling of aerodynamic forces to one or more of the feather's intrinsic structural resonance frequencies. We investigated how mode of flutter varied among a sample of hummingbird tail feathers tested in a wind tunnel. Feather vibration was measured directly at ~100 points acros...

In a recent decade, the GPS has been introduced to directly measure the displacements of super long-span bridges. However, due to its high cost, it is not appropriate to apply a number of GPS receivers in a super-long span bridge in order to measure the displacements through the overall bridge. From the limited point-based measurements of the displacement, a mode shape model for the bridge main...