Abstract
This paper presents a semi-analytical method for analysing the through-thickness stress and displacement distributions in simply supported functionally graded (FG) sandwich plates under thermal loading. The formulation is based on theory of elasticity equations leading to ordinary differential equations (ODEs) with a two-point boundary value problem approach. In this method ad-hoc assumptions are not made on displacements and stresses. The material properties (modulus of elasticity, coefficient of thermal expansion and thermal conductivity) vary according to a power law in the thickness direction, while the Poisson's ratio is kept constant throughout the depth of the plate. The plate is subjected to a temperature gradient across its thickness using Fourier heat conduction law, and the thermal response of the FG sandwich plate is evaluated in terms of stresses and displacements. Semi-analytical formulation in this study is validated for pure FGM plate under thermal load and results are compared with those of higher order theory to establish the efficacy and efficiency of the presented method. The study provides a comprehensive behaviour of FG sandwich plates under thermal loading, highlighting the importance of accurate modelling and analysis. The results presented in this theory can be served as benchmark solutions in absence of exact solutions.
Key Words
exact thermal profile; heat conduction; initial value problem; Power law; power law; sandwich FGM; semi-analytical method
Address
Rohan S. Bhagat, Sandeep S. Pendhari, Sunil S. Yadav and Yuwaraj M. Ghugal: Department of Structural Engineering, Veermata Jijabai, Technological Institute, H. R. Mahajani Marg, Matunga, Mumbai, 400019, Maharashtra, India
Abstract
Sandwich shell panels are widely used in many engineering structures wherein those are subjected to dynamic forces, which leads to their failure. It is necessary to perform accurate dynamic analysis of multilayered sandwich shell panels to provide their safe design. To the best of the authors' knowledge, literature on the free vibration analysis of multi-layered sandwich shallow shells is limited and needs more attention. Therefore, the purpose of the present study is to find higher-order closed-form solutions for the free vibration problems of sandwich shallow shells with double curvature using refined computational model. In the present study, a new hyperbolic shape function is introduced in the refined shell theory to account for the effects of transverse shear and normal deformations. A theory involves six degrees of freedom and satisfies traction-free boundary conditions at the top and the bottom surfaces of the shell. The governing equations of motion and associated boundary conditions of the theory are produced by employing Hamilton's principle. Semi-analytical closed-form solutions for the free vibration problems are made by the Navier technique for simply supported boundary conditions of the shell. The nondimensional natural frequencies of five layered symmetric and anti-symmetric sandwich shells are obtained for various parameters such as a/h ratio, a/b ratio, tc/tf ratio, radii of curvature, and modes of vibration. The present results are compared with results that have already been published to confirm the accuracy and efficiency of the current higher-order hyperbolic shell theory. It is concluded from the comparison of results that the present theory is in excellent agreement while predicting the natural frequencies of sandwich plates and shells. Also, this study presented new benchmarks in vibration analysis of sandwich shells. This study demonstrates results for a typical fivelayer sandwich shell with composite faces and isotropic/foam cores. However, the proposed model can be readily extended to other material combinations and structural configurations.
Key Words
double-curvature; free vibration analysis; hyperbolic shell theory; sandwich shells; transverse normal strain
Address
Ajim S. Shaikh: Department of Civil Engineering, Sanjivani College of Engineering, Savitribai Phule Pune University,
Kopargaon, 423603, Maharashtra, India
Atteshamuddin S. Sayyad: Department of Structural Engineering, Sanjivani College of Engineering, Savitribai Phule Pune University, Kopargaon, 423603, Maharashtra, India
Abstract
Traditional analyses of cylindrical shells often neglect spinning motion, treating them as static/quasi-static structures, which leads to deviations in vibration, stress, and stability assessments. Current research on moving loadinduced vibrations also overlooks spin rotation effects. This study investigates the time-dependent nonlinear dynamics of graphene-enhanced metal foam cylindrical shells (GPLRMF) with spinning motion. Using the firstorder shear deformation theory and Galerkin's method for discretization, we develop an analytical framework validated via comparative analyses and convergence checks. Numerical integration (Runge-Kutta method) reveals a counterintuitive phenomenon: increasing spin rotation reduces vibration amplitudes. The study systematically evaluates spin motion, geometric imperfections, and other parameters, providing design guidelines for rotating shells under transient loading.
Key Words
cylindrical shells; geometric imperfection; spinning motion; thermal environment
Address
Qiong Shi, Wu-Bin Shan, Nan-Nan Zhang: Hunan Electrical College of Technology, 411101, Xiangtan, PR China
Huan Li: Changsha Environmental Protection College, Changsha, 410004, PR China
Abstract
In the present work, we present an explicit analytical solution for calculating the flexural and interfacial behavior of beams strengthened by prestressed bonded plates. Unlike existing approaches, our method comprehensively integrates shear-lag deformations from both the beam and the plate, thus providing a more accurate prediction of critical interfacial stresses and overall composite behavior. A parametric analysis was conducted to examine how variations in parameters such as prestress force and the geometric and mechanical characteristics of the reinforcement plate impact the behavior of the interface. These variations were found to significantly influence the maximum shear and normal stress within the composite element.
Key Words
bending; interfacial stresses; plate prestressed; shear deformation; strengthening
Address
Abdelghani Brahimi: Department of Civil Engineering, Faculty of Science and Technology, University of Naama, 45000, Algeria; Artificial Intelligence Laboratory for Mechanical and Civil Structures, and Soil, University of Naama,
45000, Algeria
Boucif Guenaneche: Department of Civil Engineering, Faculty of Science and Technology, University of Ain Temouchent,
46000, Algeria
Okkacha Youb: Scientific and Technical Research Centre on Arid Regions (CRSTRA), Omar el Bernaoui, BP 1682 ,07000 Biskra, Algeria
Sidi Mohamed Bennaceur: Department of Civil Engineering, Faculty of Science and Technology, University of Naama, 45000, Algeria; Artificial Intelligence Laboratory for Mechanical and Civil Structures, and Soil, University of Naama, 45000, Algeria
Khaled Amara: Department of Civil Engineering, Faculty of Science and Technology, University of Ain Temouchent,
46000, Algeria; Engineering and Sustainable Development Laboratory, Ain Temouchent, 46000, Algeria
Abstract
This study investigated the strengthening mechanisms and failure analysis of dissimilar welded joints between SS304L stainless steel and EN24T mild steel. The mechanical characteristics and tensile failure performance of the joints were evaluated. The microstructures of different joint configurations (MS-MS, MS-SS, SS-GI, and MSGI) were first examined using SEM and EBSD analysis. Subsequently, tensile tests were conducted on four samples of these joints, which were prepared according to the ASME E8 standard. The MS-SS dissimilar welded joint exhibited the maximum load capacity of 35.71 KN, while the SS-GI joint showed the minimum capacity of 27.49 KN. The effects of weld thickness and specimen length on the strength of the joint structure were also studied. A Finite Element Method (FEM) model was developed for all cases and validated against the experimental results. The proposed FEM model shows very good agreement with the experimental data. The yield strengths of the dissimilar metal joints, as obtained from the UTM, were 320 MPa for MS-MS, 384 MPa for MS-SS, 343 MPa for MS-GI, and 325 MPa for SS-GI. This research demonstrates that the dissimilar metal weld joint, particularly the MS-SS configuration, is an effective and suitable choice for application in milk tanker structures.
Key Words
dissimilar weld failure analysis; FEM; fractography; tensile test
Address
Shivaji G. Chavan, Milind B. Patil: Production Engineering Department, VJTI, Matunga, Mumbai, 400019, India
D.N. Raut: Production Engineering Department, VJTI, Matunga, Mumbai, 400019, India; VJTI Mumbai, Mumbai, Maharashtra 400019, India
