Mathematical modeling and numerical seismic study of smart concrete beams

The seismic response of the smart layer is studied in this article based on mathematical modeling and numerical solution. The structure is modeled by sinusoidal shear deformation (SSDT) and the motion equations are derived by energy method and virtual work. The concrete beam is covered by a piezoelectric layer for smart control of the structure. The differential quadrature (DQ) and Newark methods are applied for numerical solution and dynamic response of the smart concrete beam under the earthquake load. The influences of boundary conditions; external voltage, and geometrical parameters of the beam are studied on the seismic response of the smart concrete beam. The results indicate that by applying an external negative voltage, the dynamic deflection of the smart concrete beam is reduced, which is important for smart control of the system while this phenomenon is converse for positive external voltage

Current global scenario of sputtered deposited NiTi smart systems

This review provides details of the global scenario on the recent development and application of NiTi smart metal shape memory alloys (SMA). It mainly focuses on the dc/rf magnetron sputtering fabrication technology of nitinol thin film, which is a prominent structural material for many miniaturised systems. The sputtering parameters and their influence on the smart mechanism of the NiTi thin film has highlighted. The application of NiTi SMA at industrial scale from aviation industries to medical industries was discussed. The raised challenges within various applications were addressed, discussed and we have proposed possible way to overcome these limitations

EXACT SOLUTION FOR TEMPERATURE-DEPENDENT BUCKLING ANALYSIS OF FG-CNT-REINFORCED MINDLIN PLATES

This research deals with the buckling analysis of nanocomposite polymeric temperature-dependent plates reinforced by single-walled carbon nanotubes (SWCNTs). For the carbon-nanotube reinforced composite (CNTRC) plate, uniform distribution (UD) and three types of functionally graded (FG) distribution patterns of SWCNT reinforcements are assumed. The material properties of FG-CNTRC plate are graded in the thickness direction and estimated based on the rule of mixture. The CNTRC is located in a elastic medium which is simulated with temperature-dependent Pasternak medium. Based on orthotropic Mindlin plate theory, the governing equations are derived using Hamilton’s principle and solved by Navier method. The influences of the volume fractions of carbon nanotubes, elastic medium, temperature and distribution type of CNTs are considered on the buckling of the plate. Results indicate that CNT distribution close to top and bottom are more efficient than those distributed nearby the mid-plane for increasing the stiffness of plates

Analytical bending solution of fully clamped orthotropic rectangular plates resting on elastic foundations by the finite integral transform method

This study presents exact bending solution of fully clamped orthotropic rectangular plates subjected to arbitrary loads resting on elastic foundations, based on the finite integral transform method. In this method, it is not necessary to determine the deformation function because the basic governing equations of the classical plate theory for orthotropic plates have been used. A detailed parametric study is conducted to elucidate the influences of stiffness of elastic medium, plate length, flexural rigidities and distributed transverse load on the deflections. The applicability of the method is extensive since it can solve any plates with different loadings. Numerical results are presented to demonstrate the validity and accuracy of the approach, as it is totally in agreement with the other studies

Dynamic Stability Analysis in Hybrid Nanocomposite Polymer Beams Reinforced by Carbon Fibers and Carbon Nanotubes

The objective of this innovative research is assessment of dynamic stability for a hybrid nanocomposite polymer beam. The considered beam formed by multiphase nanocomposite, including polymer–carbon nanotubes (CNTs)–carbon fibers (CFs). Hence, as to compute the effective material characteristics related to multiphase nanocomposite layers, the Halpin–Tsai model, as well as micromechanics equations are employed. To model the structure realistically, exponential shear deformation beam theory (ESDBT) is applied and using energy methods, governing equations are achieved. Moreover, differential quadrature method (DQM) as well as Bolotin procedures are used for solving the obtained governing equations and the dynamic instability region (DIR) relative to the beam is determined. To extend this novel research, various parameters pinpointing the influences of CNT volume fraction, CFs volume percent, boundary edges as well as the structure’s geometric variables on the dynamic behavior of the beam are presented. The results were validated with the theoretical and experimental results of other published papers. The outcomes reveal that increment of volume fraction of CNT is able to shift DIR to more amounts of frequency. Further, rise of carbon fibers volume percent leads to increase the excitation frequency of this structure