The characterization of the presence bubbles in industrial fluid circuits may be extremely important for many safety issuses. It is well known that acoustic properties liquids can drastically modified by a small amount gaz content liquid. At sufficiently low frequencies, speed sound depends primarily on gas volume fraction. variation fraction then induce some variations vibroacoustic behavior p...

The modal vibration characteristics of new MEMS (microelectromechanical systems) ultrasonic sensors have been studied theoretically and experimentally. Such studies are needed in order to design MEMS sensors with improved sensitivity for detection of ultrasound. The determination of vibration behavior of such sensors is critical for a successful design, and a validated vibration characterizatio...

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 ...

the nonlinear static procedures (nsps) proposed by design codes do not lead to reliable results especially for tall buildings. they generally provide inconsistent estimates of inelastic seismic demands, especially for the top floors due to their inabilities in considering the higher modes effects. in this paper, a new enhanced pushover procedure is proposed which is based on the envelope of the...

The fundamental frequencies and mode shapes of steel and carbon fiber–reinforced plastic (CFRP) cylindrical shells with steel inserts were investigated using finite element analysis and modal testing. The free-free boundary condition was tested with modal testing using the roving hammer method and verified by finite element analysis using ABAQUS. The results show good agreement between the test...