ABSTRACT
The nonlinear frequency response of bi-directional functionally graded porous beams experienced range of various end conditions is investigated in this work. The end conditions which are simply supported, clamped-simply supported, clamped-clamped, and clamped-free are taken by using the Von Karman geometric nonlinearity, Green's tensor and Reddy third-order shear deformation theory. A generalized differential quadrature technique (GDQM) accompanied by direct numerical iterance approach is proposed to solve equations. The findings are presented to aid in future research into the effects of various gradient indices, vibration amplitude ratios, porosity coefficients, shear and elastic substrate parameters, boundary conditions, and vibration frequencies on the bi-directional functionally graded beams. The outcomes of this research have practical applications and can be utilized to enhance the design of bi-directional beams. The results are also highly useful in anticipating and identifying potential causes of failure in these beams.
ABSTRACT
This article proposes an innovative viscosity sensor based on the thickness-shear vibration of stress compensated (SC)-cut quartz resonator. The thickness-shear mode is first analyzed and further studied with fluid-structure interaction between the resonator and the viscous fluid loading. The characteristic equation is derived based on the 3-D linear piezoelectric equations and solved for sensitivity analysis. Then laboratory experiment is carried out to validate the theory. To conduct the viscosity measurement, the SC-cut quartz resonator is integrated with a U-tube test fixture, which is designed and fabricated for sensor housing to avoid the influence of the mass of the fluid. The resonator is tested with various viscosities by tuning the ratio of glycerol/water mixture. Experiment results show consistency with the analytical solution, which together present an improved sensitivity of viscosity measurement by using SC-cut quartz resonator comparing to other resonator-based viscosity sensors. The proposed viscosity sensor is sensitive, accurate, and portable, and therefore can be applied to real-time, on-site measurement or sampling of fluidic samples.
Subject(s)
Quartz , Vibration , ViscosityABSTRACT
Lanthanum-gallium tantalate (LGT) is a member of the LGX crystal family (langasite, langanite, and langatate) known for high-quality factor and stability at higher temperatures. These characteristics enable filters and sensors for use in harsh environments. Accurate values for the second-order material constants are required for electromechanical modeling of such devices. A sufficient set of bulk acoustic wave (BAW) propagation velocities have been measured in cube-shaped samples to obtain the full set of second-order elastic and piezoelectric material constants along with the experimental uncertainties. The cross correlation method was used to accurately measure the time-of-flight (TOF) values between the first two back-wall echoes under a constant room-temperature environment. The calculated BAW velocities and extracted material constants show good agreement with earlier work.
