In this work, a general electroelastic solution method is developed for size-dependent electric potential, deformation, strain and stress analysis of a piezoelectric double curved nanoshell using a shear deformable model and nonlocal elasticity theory for a Levy-type boundary condition through Eigenvalue- Eigenvector approach. The partial differential equations derived using principle of virtual work are reduced to ordinary differential equations after applying the Levy-type boundary condition. The general solution is derived using Eigenvalue-Eigenvector approach with applying the clamped-clamped boundary conditions. Accuracy of the proposed solution is justified through comparison with results of previous papers. The electroelastic deformation, strain and stress are presented in terms of scale parameter and initial voltage. The main novelty of the present paper is application of a more general solution method for investigating effect of various boundary conditions on the electro-elastic responses of the shell. Furthermore, an investigation on the effect of scale parameter associated with the Eringen nonlocal elasticity theory is studied on the deformation, strain and stress results.

The strains and kinetic energies of a vibrating cylindrical shell are obtained in an integral form to describe the current shell problem. Three unknown displacement functions are used to generate three differential equations. The shell frequency equation is obtained using the Galerkin method. The MATLAB program are used to solve the frequency equation for the vibration of cylindrical shell. In this case, it is assumed that the cylindrical shell is made of material that works well. These tools include parts made of ceramics and metals. For this purpose, functionally graded items are selected. To exchange elements in the shell, the composition of material is controlled by a power law. The frequency coupling (Hz) vary as a function of volume fraction index, length-to-radius ratio, and height-to-radius ratio. The metal-ceramic material captures the frequency of the wave numbers using a limited range of parameters. It can be seen that the frequencies of clamped-free is less than the clamped-clamped. As the power law exponent increases, the frequency increases. The present finding is supported by previous research.

By employing the Generalized Differential Quadrature (GDQ) technique alongside adaptive modeling through Artificial Neural Networks (ANN), the intrinsic vibrational properties of annular sandwich plates resting on an elastic foundation have been comprehensively examined within a thermal context. The sandwich structure features a core composed of graphene platelets, enveloped by two functionally graded (FG) layers. The Halpin-Tsai micromechanical model was utilized to ascertain the material properties of the composite structure. Furthermore, the material characteristics of the two FGM face sheets exhibit a continuous variation across the thickness, conforming to a power-law distribution. The governing partial differential equations and boundary conditions of the plate are formulated using the third-order shear deformation theory (TSDT) in accordance with Hamilton's principle. These equations are discretized in the spatial domain via the GDQ method, enabling the calculation of the natural frequencies of the plates. The precision of the numerical approach is validated by juxtaposing the results with existing literature. Additionally, an adaptive ANN is employed to forecast the frequencies of the sandwich annular plates. This methodology involves training a Neural Network (NN) with a dataset of frequency solutions derived from the GDQ method. The Levenberg-Marquardt backpropagation algorithm is utilized for the training process. Subsequently, the ANN model is refined for accurate predictions in novel scenarios. The findings indicate that both the GDQ method and the adaptive ANN can reliably predict the frequencies of the sandwich structure featuring a graphene platelet-reinforced core. The study explores the impact of various factors, including the FG power index, volume fraction of graphene platelets, the presence of an elastic foundation, and temperature variations on the natural vibrational behavior of annular sandwich plates supported on an elastic foundation. The ANN model proves to be highly effective for predicting the natural frequency of the sandwich disk, significantly reducing computational time and costs. It has been demonstrated that the proposed ANN model can accurately forecast natural frequencies without necessitating the resolution of any differential equations or engaging in time-consuming other numerical methods or procedures.

The horizontal bar is a staple of men's gymnastics which allows athletes to perform spectacular routines such as swings, releases, and complex dismounts. This bar must endure significant vibrations and stress when the gymnast stands about 3 meters above the ground. This study proposes replacing traditional horizontal bars with lightweight and porous metal foam cylinders that are able to handle mechanical and thermal challenges. Three porosity patterns namely Uniform Porosity Pattern (UPP), Symmetric PP (SPP), and asymmetric (APP) are explored here to examine their effect on the above-mentioned metal foam. Also, the behavior of these bars under various thermal and material conditions is studied through the first-order shear deformation theory and Hamilton's principle. The results indicate how porosity, thickness, and thermal condition would influence the bar's wave frequency and velocity. For instance, the findings show that higher temperatures, radius to thickness ratio and porosity would decrease wave frequencies. Moreover, wave number has positive effect on values of wave frequency and phase velocity. Additionally, these outcomes prove the potential of metal foams in more efficient designs in sports equipment.

Cold-formed steel (CFS) walls with infilled material have become more and more popular due to their improvement in strength and stiffness of the walls. Previous studies have proved the structural advantage of gypsum-filled CFS shear walls. However, when applied in structural systems, there are lack of guidelines in seismic design for the novel CFS shear walls. In this paper, on basis of previous gypsum-filled CFS shear wall tests, the simplified model based on equivalent line elements was put forward and verified. The results indicate the proposed simplified model can effectively simulate the hysteretic behavior of the walls, which can be applied to analyses of structural systems. And then the reduction response factor R was developed on basis of tests and Newmark method, which played an important role on seismic design. Based on proposed reduction response factor R and simplified model, the archetype structures were designed and their 3D models were built. And then a series of pushover analyses and incremental dynamic analyses were conducted to evaluate the collapse performance of the structures. The results indicate that reduction response factor R of 4.6 for the gypsum-filled CFS shear walls can be employed in seismic design.

Composite girders with corrugated steel webs (CSWs) represent a highly promising structure type worldwide. This paper proposed a novel finite element (FE) model named the spatial grillage model (SGM) to simulate and analyze composite girders with CSWs, which balances simplicity and accuracy. Firstly, the mechanical behavior and orthogonal stiffness of CSWs were examined, followed by the simulation methodology by the cruciform grids. Subsequently, the spatial grillage model (SGM) was established, wherein concrete flanges were modeled as conventional individual girders or planar grillages according to their widths and then connected to the cruciform grids of CSWs by rigid arms. The feasibility of the proposed model was demonstrated by a thorough comparison with ANSYS solid/shell models. The results show that the proposed model achieves high accuracy in static, modal, and global buckling analyses with a greatly reduced number of elements. Regarding the buckling at the component level, particularly concerning the local buckling of CSWs, the proposed model demonstrates conservative predictions for the buckling load factor, necessitating the integration of critical shear stress criteria to achieve more precise control. In the end, the engineering application prospects were discussed and conclusions were drawn.