Recent research advances in the dynamic behavior of shells: 1989-2000, Part 1: Laminated composite shells

Electro-thermo-torsional buckling response of a double-walled boron nitride nanotube (DWBNNT) has been investigated based on nonlocal elasticity and piezoelasticity theories. The effects of surrounding elastic medium such as the spring constant of the Winkler-type and the shear constant of the Pasternak-type are taken into account. The van der Waals (vdW) forces are considered between inner and outer layers of nanotube. According to the relationship between the piezoelectric coefficient of armchair boron nitride nanotubes (BNNTs) and stresses, the first order shear deformation theory (FSDT) is used. Energy method and Hamilton’s principle are employed to obtain coupled differential equations containing displacements, rotations and electric potential terms. The detailed parameter study is conducted to investigate the effects of nonlocal parameter, elastic foundation modulus, temperature change, piezoelectric and dielectric constants on the critical torsional buckling load. Results indicate that the critical buckling load decreases when piezoelectric effect is considered.

Electro-thermo-torsional buckling of an embedded armchair DWBNNT using nonlocal shear deformable shell model

The present approach considers hybrid control strategy to reduce the amount of transmitted sound through a multilayered doubly curved sandwich shell equipped with piezoelectric layer and shunt circ...

Hybrid control technique for vibroacoustic performance analysis of a smart doubly curved sandwich structure considering sensor and actuator layers

When doing dynamic measurement using an electromechanical transducer for both sensing and actuating simultaneously, loading effect of the transducer is obviously large enough to jeopardize measurement accuracy This paper examines the role of a newly introduced ‘transduction matrix’ in decoupling the loading effect from a piezoceramic inertial actuator (PIA) which is employed to detect pseudo mechanical impedance of a structure as both exciter and sensor simultaneously The two by two transduction matrix characterizes the relationship between the input electrical variables and the output mechanical variables of the PIA Once it is properly calibrated, the mechanical impedance of the structure can be indirectly detected via measuring the input electrical impedance of the actuator In this presentation, the appropriateness of a numerical model of the PIA is first validated through comparison with experimental results Then, the influences of design parameters of PIA on its transduction matrix as well as measurement accuracy are studied numerically in detail The results show that, although the transduction matrix varies significantly due to changes of design parameters, the detected mechanical impedance remains the same for a given structure, as the loading effect of the PIA is satisfactorily decoupled

Decoupling loading effect in simultaneous sensing and actuating for dynamic measurement

A multi-objective mixed H2/H∞ robust output feedback control synthesis with regional pole placement constraints in a linear matrix inequalities framework is adopted for active low-frequency sound radiation control of an arbitrarily thick, rigidly baffled, simply supported, multi-layered piezo-composite circular panel. The adopted control system concurrently captures the benefits of both H2 transient control performance and H∞ robust stability in the face of external disturbances and system uncertainties. Also, the implemented volumetric sensing/actuation configuration avoids the typical problems associated with conventional (spatially discrete) piezoelectric sensor/actuator patches, where the total volume velocity can be effectively cancelled with the main contribution being to the long wavelength acoustic power emission. The elasto-acoustic analysis is based on the spatial state-space method in the context of exact 3D elasticity theory along with the Rayleigh integral formula where Neumann’s addition the...

https://journals.sagepub.com/doi/pdf/10.1177/0263092316644085

C. Balaji Kumar

Papers

Segmented Sensors and Actuators for Thick Plates and Shells Part i: Analysis Using Fsdt

Segmented sensors and actuators for thick plates and shells part ii: parametric study