A cell-based smoothed discrete shear gap method (CS-FEM-DSG3) for dynamic response of laminated composite plate subjected to blast loading

The paper investigates the dynamic response of laminated composite plate under the effect of blast loading. The cell-based smoothed discrete shear gap method (CS-FEM-DSG3) based on the first-order shear deformation theory (FSDT) and the equivalent layer theory (ELT) is used to model the behavior of the laminated composite plate. The blast loading is simulated by a time diagram of rectangular, triangular, exponential, or sinusoidal shape. The effects of the number of layers and fiber orientation to the displacement and stress fields of the laminated composite plate are discussed. Numerical results demonstrated the accuracy and reliability of the present method compared with previous published methods

A new inverse trigonometric shear deformation theory for isotropic and functionally graded sandwich plates

A new inverse trigonometric shear deformation theory is proposed for the static, buckling and free vibration analyses of isotropic and functionally graded (FG) sandwich plates. It accounts for a inverse trigonometric distribution of transverse shear stress and satisfies the traction free boundary conditions. Equations of motion obtained here are solved for three types of FG plates: FG plates, sandwich plates with FG core and sandwich plates with FG faces. Closed-form solutions are obtained to predict the deflections, stresses, critical buckling loads and natural frequencies of simply supported plates. A good agreement between the obtained predictions and the available solutions of existing shear deformation theories is found to demonstrate the accuracy of the proposed theory

The role of information technology in STEM education

The ubiquity of IT (Information technology) for teaching at large is a reality that can be observed, including STEM education, which is the field of study of this research. In view of this situation, this work is intended to determine the role of IT in STEM (Science, Technology, Engineering, Mathematics) education. It was decided to conduct a systematic review based on PRISMA model and adding information obtained from the analysis of fugitive literature. The literature review was carried out on a total of 16 articles. The main inclusion criteria were a temporal selection from 2015 to March 2023, the inclusion of the terms IT and STEM in the title, abstract or keywords of the articles. The main results show an increasing tendency of this topic, especially in English research. Most relevant conclusions of the systematic review evidence a positive relationship between IT and STEM education, although some negative aspects are also highlighted as there is still a lack of resources and teacher training, leading to ineffective application of IT in STEM classes. The research results have important practical implications, it motivates teachers to research, propose and implement measures to enhance the role of IT in STEM education, while minimizing the limitations that have been identified

Static and vibration analysis of isotropic and functionally graded sandwich plates using an edge-based MITC3 finite elements

Static and vibration analysis of isotropic and functionally graded sandwich plates using a higher-order shear deformation theory is presented in this paper. Lagrangian functional is used to derive the equations of motion. The mixed interpolation of tensorial components (MITC) approach and edge-based-strain technique is used to solve problems. A MITC3 three-node triangle element with 7 degree-of-freedoms per nodes that only requires the C0-type continuity is developed. Numerical results for isotropic and functionally graded sandwich plates with different boundary conditions are proposed to validate the developed theory and to investigate effects of material distribution, side-to-thickness ratio, thickness ratio of layers and boundary conditions on the deflection, stresses and natural frequencies of the plates

Environmentally friendly and animal free leather: Fabrication and characterization

Environmentally friendly and animal free leather also known as "vegan leather" or ''artificial leather'', is an alternative biomaterial produced without the use of any animal component. This biobased material compared to traditional leather shows similar physico-chemical and mechanical properties. Moreover, recent studies show that this class of materials are gradually gaining market in the fashion industry as leather substitutes. In the present study, efforts toward the preparation of such biobased materials using novel formulations agro-waste components is accomplished. Different compositions of the leather-like materials are successfully fabricated using waste maple leave (5-10%) and apple fruit (0-10%) pulp, mixed with additives such as kombucha biomass cellulose (25-40%), biodegradable polyesters (0-25%), and plasticizers (5-20%). The prepared biocomposite materials are characterized for morphology, mechanical, adhesion, and water absorptive properties. SEM results confirm that the fabricated biocomposites are porous and breathable. In addition, tensile, DMA, and adhesion analysis showed that the materials are flexible with considerable mechanical strength. To conclude, this material may be considered as a prospective leather alternative for application in leather accessories, such as handbags and upper shoe sole. © 2020 American Institute of Physics Inc.. All rights reserved

Static and free vibration analyses of laminated composite shells by cell-based smoothed discrete shear gap method (CS-DSG3) using three-node triangular elements

A cell-based smoothed discrete shear gap method (CS-DSG3) using three-node triangular elements was recently proposed to improve the performance of the discrete shear gap method (DSG3) for static and free vibration analyses of isotropic Reissner-Mindlin plates and shells. In this paper, the CS-DSG3 is further extended for static and free vibration analyses of laminated composite shells. In the present method, the first-order shear deformation theory (FSDT) is used in the formulation due to the simplicity and computational efficiency. The accuracy and reliability of the proposed method are verified by comparing its numerical solutions with those of others available numerical results

Analyses of stiffened plates resting on the viscoelastic foundation subjected to a moving vehicle by a cell-based smoothed triangular plate element

Recently, a cell-based smoothed discrete shear gap method (CS-FEM-DSG3) based on the firstorder shear deformation theory (FSDT) was proposed for static and free vibration analyses of Mindlin plates. The CS-FEM-DSG3 uses three-node triangular elements that can be easily generated automatically for arbitrary complicated geometric domains. This paper further extends the CS-FEMDSG3 for static, free vibration, and dynamic response of the stiffened plate resting on viscoelastic foundation subjected to a moving vehicle. The viscoelastic foundation is modeled by discrete springs and dampers whereas the stiffened plate can be considered as the combination between the Mindlin plate and the Timoshenko beam elements. The moving vehicle is transformed into one concentrated load at its central point. Some numerical examples are investigated and numerical results show that the CS-FEMDSG3 overcomes shear-locking phenomena and has a fast convergence. The results also illustrate the good agreement of the CS-FEM-DSG3 for static and free vibration analyses of un-stiffened plate compared with the previous published methods. In addition, the numerical results for dynamic analysis of stiffened plates by the CS-FEM-DSG3 also show the expected property in which the deflection of the stiffened plate is much smaller than those of the un-stiffened plate