buckling under compression is a common phenomenon for thin-walled structures. Under certain conditions, they can also buckle locally under tensile loads. In this paper, the buckling of cracked panels is investigated. Effects of some parameters such as the length and orientation of crack, length, width and thickness of the panel and boundary conditions on the Compressive and tensile buckling loads are determined. The results show that the dimensions of panels have the least and characteristics of crack have the most effect on the buckling.

: In this research, the electro-optical aspects of Tetra-Hexagonal-Carbon allotrope as a two-dimensional nanostructure under Compressive buckling parameter based on density functional theory (DFT) with PBE-GGA full potential approximation method using simulation software and computational codes based on first-principles calculations have been investigated. The analysis of the results obtained from the calculations of the electronic properties of this nanostructure, such as the band gap and density of states (DOS) under buckling change, indicates that the energy band gap of this nanosheet as a direct band gap semiconductor with 1.61 eV, increases slightly under the influence of the Compressive buckling factor and then decreases down to 1.11 eV by applying higher Compressive buckling factors. The optical properties of this nanosheet have smooth and regular changes in the out-of-plane polarization, by applying Compressive buckling conditions in the visible light spectrum. Also, according to the obtained results, an acceptable match between the electronic and optical properties of this two-dimensional nanostructure is observed, which indicates the correspondence of electronic and optical behaviors, which can predict this carbon nanosheet is a suitable material for designing electro-optical devices.

A buckling analysis of rectangular laminated composite plates with an edge delamination under in-plane Compressive loading is performed using the finite element method. Such plates may be considered as simplified models of stiffener plates of a stiffened panel. The buckling load and buckling mode are obtained by solving an eigenproblem. In an unconstrained analysis, physically inadmissible modes may appear because of the overlap between separated sublaminates in the delaminated region. To eliminate overlap, constraints are added iteratively on the entire overlapped area using penalty function method. The validity and superiority of the analysis method in predicting buckling load and buckling mode are shown in comparison with the experimental and analytical results available in the literature. Numerical results show the effect of delamination width and depth and boundary conditions on the buckling load.

This article investigates the buckling behavior of orthotropic annular/circular bilayer graphene sheet embedded in Winkler– Pasternak elastic medium under mechanical loading. Using the nonlocal elasticity theory, the bilayer graphene sheet is modeled as a nonlocal orthotropic plate which contains small scale effect and van der Waals interaction forces. Differential Quadrature Method (DQM) is employed to solve the governing equations for various combinations of simply supported or clamped boundary conditions. The results show that small scale parameter does not have any effect on critical buckling load of cases without elastic medium in simply supported boundary condition. Also, increase of vdW coefficient leads to increase of critical buckling load smoothly then it has no impact on critical buckling load after a certain value.

In this research, mechanical buckling of rectangular plates of functionally graded materials (FGMs) is considered. Equilibrium and stability equations of a FGM rectangular plate under uniform in-plane compression are derived. For isotropic materials, convergent buckling loads have been presented for non-uniformly compressed rectangular plates based on a rigorous superposition Fourier solution for the in-plane Airy stress field and Galerkin's approach for stability analysis. The results for isotropic case will be compared with reference articles and finite element method (FEM) solution. Finally, the results will be achieved for a sample of FGM material as well as the research on the effect of power law index on buckling coefficient.

The buckling behavior of functionally graded carbon nanotube (FG-CNT) reinforced polymer-based moderately-thick plates subjected to in-plane biaxial Compressive loads in elastic and thermal environments in the framework of first-order shear deformation plate theory (FSDPT) is investigated. First, the temperature-dependent properties of CNTs and nanocomposites are defined and their constitutive relations are established, then the stability and strain compatibility equations in elastic media are derived in the framework of the FSDPT. Then, by applying the Galerkin method to the basic equations, a closed-form solution is obtained for the critical biaxial Compressive loads. The specific numerical analyzes and interpretations are made for various plate sizes and CNT patterns on the Winkler elastic foundation and in thermal environments within FSDPT and classical plate theory (CPT).

Background and Aim: ZOE has been used in different fields of dentistry for many years. A locally produced component (Zoliran) has been recently introduced to the marketwith similar characteristic to the original Zonalin. Because of a lower cost involved to use Zoliran cement and its availability, confirm reliability of its physical properties. This investigation was designed to assess the Compressive strength of Zoliran cement in comparison to Zonalin cement as the standard material. Materials and Methods: Five samples with dimension of 4mmx6mm of each cement were provided and stored in distilled water in 370C±10C for a period of 24 hours. The lowest load of force was registered as the reference to which the sample could be broken by(according to the criteria No: 30 of ANSIIADA). The value of Compressive strength was then calculated using the following formula (K =4F/πD2 ). Results: The mean Compressive strength of five samples was measuredas: 14.33 Mpa for Zoliran cement and 31.83 Mpa for Zonalin cement. The mean Compressive strength of Zonalincement was significantly higher than the mean suggested in ANSl/ADA Specification No.30. The mean Compressivestrength of Zoliran cement was also lower than the mean value registered in ANSI/ADA SpecificationNo.30. Conclusion: Compressive strength of Zoliran cement was significantlylower than that of Zonalin cement. Further tests are required to compare the other physical properties of this material before it can be clinically recommended.

In this study the ultimate amount of buckling load applied to the composite conical lattice structure located on the Winkler-Pasternak foundation has been investigated and compared by two analytical and finite elements methods. First, the governing equations of the conical lattice structure were obtained and then, by placing the conical lattice structure on the Winkler-Pasternak foundation, the governing equations were derived analytically. The effect of foundation stiffness coefficient on the behavior of conical lattice structures has been investigated analytically by considering different values. As the number of ribs and their cross section increases, the strength of the structure increases and by assuming that the conical lattice structure resting on the Winkler-Pasternak foundation, the amount of buckling load will increase and with increasing stiffness coefficient for the spring in the foundation, the buckling load resistance decreases. By comparing the analytical results and the finite element method, it can be seen that the analytical method and the obtained formula have a suitable accuracy for investigating the buckling of the lattice structure on the Winkler-Pasternak foundation.