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This paper investigates dynamic results of a small-scale-dependent panel subjected to a combination of mechanical, electrical, and magnetic loads using the shear defamation theory. Modified couple stress theory (MCST) is used for accounting small-scale effects in small sizes. Governing equations of motion are derived based on Hamilton's principle in the cylindrical coordinate system. The micro panel is composed of an elastic core integrated with two piezoelectric/piezomagnetic layers at top and bottom. Microlength scale parameter is included in the couple stress tensor and symmetric curvature tensor to capture size dependency. The analytical solution is applied for the solution of the motion equations. The extended parametric results are provided to show natural frequencies in terms of main significant input parameters such as initial electric/magnetic loads, span angle, length to thickness, radius to thickness, and length to radius ratio. Furthermore, the effect of higher mode numbers along the axial and circumferential directions is studied on the responses. The numerical results indicate that the natural frequencies are increased with an increase in initial magnetic potential and a decrease in initial electric potential. [ABSTRACT FROM AUTHOR]

The mechanical and thermal stability equations of asymmetric functionally graded discs subjected to the Pasternak foundation are developed by employing Hamilton’s energy principle based on the first-order shear theory. The material properties are temperature-dependent and vary according to power-law and exponentially in thickness and radial direction, respectively. Accordingly, the temperatu re is also varying in both directions. Using the well-developed differential quadrature method, stability equations are discretized along with the boundary conditions, leading to a complete algebraic linear equations system. The validation of results is performed to certify the results. Numerical and illustrative results are presented to study the effect of elastic foundation parameters, graded indexes, nodal lines, and boundary conditions on thermal and mechanical buckling. Also, the impact of compressive in-plane force on thermal buckling and thermal environment on mechanical buckling is presented. [ABSTRACT FROM AUTHOR]

Limited research is available in the literature to investigate the presentation of normal strength concrete-filled steel tube (CFST) circular compression elements under compression loading by considering various material and geometric coefficients. Thus, the present study investigates the mechanical behavior of CFST compression elements employing nonlinear finite element analysis (NLFEA), empirical/theoretical modeling, and a newly developed Artificial Neural Network (ANN) model, based on a large experimental database of 1223 samples. The NLFEA modeling is performed in ABAQUS (6.14) with an improved concrete damaged plasticity model for laterally restrained concrete. Various geometric and material properties are considered, for parametric NLFEA estimates preliminary validated toward the available experimental database. A new ANN model for the load-carrying capacity of CFST circular elements was also offered by employing the experimental database. The comparison between the calculations of the NLFEA model, empirical model, and ANN model displayed a close agreement with the database results. [ABSTRACT FROM AUTHOR]

In the current paper, hygro-thermo-magnetically induced vibrations of small-scale viscoelastic tubes containing flow with a spin motion under gravity and tangential loads are analyzed by including surface effects. The dynamic equations are derived in the framework of the modified nonlocal elasticity theory (NET) and Rayleigh beam model. The Galerkin method and Laplace transformation are implemented to solve model equations. Vibration frequencies, stability boundaries, and Campbell diagrams of the system are acquired. Impacts of influential parameters such as scale rotary inertia factor, scale parameter, viscoelastic materials, gravity and tangential loads, flow and spin velocities, geometrical properties, and environmental conditions on the stability of the structure are examined. Also, the obtained results are compared for the Rayleigh and Euler-Bernoulli (EB) beam models. The golden results of this work are that by fine-adjusting the scale parameter and magnetic intensity in the system, destructive effects of hygro-thermal loads can be dampened. Besides, the increment of the rotary inertia factor and nanotube thickness induces destabilizing effect on the system. [ABSTRACT FROM AUTHOR]

Hybrid renewable energy systems using solar energy and biomass will become more crucial in the near future. In this study a new design for continuous production process of power, biogas and fresh water is proposed. The challenge of the present research is to use different sources for energy production from renewable resources simultaneously including solar and biomass to produce power, fuel and fresh water, using 4-stage Multi Effect Distillation (MED) for desalination of seawater. To cope with constant and stable energy production required for renewable solar power plants at night, due to lack of sunlight, co-consumption of hybrid solar and biomass feedstocks is considered in this system. The associated challenge is discussed by the assessments of Solar Heat transfer fluid (SHTF), Sewage sludge flowrates, biogas production, output waste stream of gasification reactor, power and fresh water production using ASPEN Plus software. The sensitivity analysis was performed to demonstrate the viability of the designed process and the resulting products. The findings of this research show that gasification process produced 76.858 ton/h syngas (CO and H 2). Besides, 34.547 MW of power with about 783 m3/h of fresh water are produced with the overall exergy efficiency of 35.51%, 52.260 MW exergy destruction and desalination efficiency of 52%. Only 25 MW of solar power is necessary due to proper energy recovery throughout the entire process. The productivity of freshwater production is 50%. 38908 m2 of Parabolic trough collector (PTC) is needed to supply required solar energy during day light hours. It is revealed that the hybridization of solar & biomass energy resources for producing power, fresh water, and biogas could be a sustainable approach to cope with the increasing demand for fresh water, electricity, and fuel. • Tri-generation process with generating power, fresh water and biogas is proposed. • The system is a continuous process using energy storage mechanism. • Tri-generation system is powered with solar PTC and biomass burning. • 34.547 M W of electric power and 783 m 3 with 52% efficiency of fresh water (4-stage MED) are produced. • The lack solar power in the night is compensated by burning 155 k g /h of the produced methane in the gasification unit. [ABSTRACT FROM AUTHOR]