STRESS DISTRIBUTION IN THE HOLLOW STIFFENED HYBRID LAMINATED COMPOSITE PANELS IN SHIP STRUCTURES UNDER SINUSOIDAL LOADING

2021 ◽  
Vol 158 (A2) ◽  
Author(s):  
M Sit ◽  
C Ray ◽  
D Biswas ◽  
B Mandal
Keyword(s):  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Computer Code ◽  
Strength Properties ◽  
Point Of View ◽  
Stiffened Panel ◽  
Hybridization Technique ◽  
Stiffened Plate ◽  
Present Formulation ◽  
Hybrid Laminates

A simplified hollow stiffened hybrid laminated plate model has been developed for the marine structures. The detailed stress analysis through the thickness of the stiffened plate based on the higher order shear deformation theory has been carried out under sinusoidal loading. The hybrid laminates are made by wrapping the GFRP laminates with CFRP at the outermost layers of the stiffened panel. This hybridization technique can be an optimum solution from the point of view of cost reduction as well as enhancement of strength properties. The layer-wise stresses for the stiffened plate have been calculated in the present paper. A 3D polynomial curve fitting technique has been used to obtain higher accuracy and consistency in the computation of stresses. The computer code has been developed using MATLAB considering the plates as eight noded isoparametric plate bending element and the stiffener has been modeled as three noded isoparametric beam element. The stiffened panel has also been analysed using the ANSYS14.0 software package considering 2D model. The results obtained from the present formulation have been compared with those available in the published literature to validate the present formulation. The stiffened panels made of GFRP, CFRP and GFRP-CFRP hybrid laminates have been studied here. An extensive parametric study has been carried out with varying fibre content in the laminates.

Thermo-Mechanical Stability Analysis of Composite Cylindrical Panels

2013 ◽  
Author(s):  
P. V. Katariya ◽  
S. K. Panda
Keyword(s):  
Mechanical Stability ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Shell Element ◽  
Element Model ◽  
Computer Code ◽  
Substantial Effect ◽  
Stability Behavior ◽  
Support Conditions ◽  
Laminated Structures

In this article, stability behavior of laminated composite curved panels under thermo-mechanical loading is analyzed. A generalized panel model is developed based on higher order shear deformation theory by taking the nonlinearity in Green-Lagrange sense for thermal distortion. The critical buckling load (mechanical/thermal) parameters are obtained by using the developed finite element model validated for both ANSYS and homemade computer code. The model has been discretized in ANSYS using an eight-noded serendipity shell element (shell281) and a nine noded isoparametric element for the computer code. The convergence test has been carried out and the results are compared with those available published literature. In this analysis, a uniform temperature distribution through the thickness is taken and the material properties for the composites are assumed to be temperature invariant. We note substantial effect of different parameters (support conditions, number of layers, thickness ratio and modular ratio) on thermo-mechanical stability behavior of laminated structures.

scholarly journals Non-linear deflection and stress analysis of laminated composite sandwich plate with elliptical cutout under different transverse loadings in hygro-thermal environment

2020 ◽  
Vol 7 (1) ◽  
pp. 80-100
Author(s):  
Rahul Kumar ◽  
Achchhe Lal ◽  
B. M. Sutaria
Keyword(s):  
Stress Concentration ◽  
Sandwich Plate ◽  
Thermal Environment ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Gauss Point ◽  
Composite Sandwich ◽  
Aspect Ratios ◽  
Present Solution ◽  
Non Linear

AbstractIn this paper, non-linear transverse deflection, stress and stress concentration factors (SCF) of isotropic and laminated composite sandwich plate (LCSP) with and without elliptical cutouts subjected to various trans-verse loadings in hygrothermal environment are studied. The basic formulation is based on secant function-based shear deformation theory (SFSDT) with von-Karman nonlinearity. The governing equation of non-linear deflection is derived using C0 finite element method (FEM) through minimum potential energy approach. Normalized trans-verse maximum deflections (NTMD) along with stress concentration factor is determined by using Newton’s Raphson method through Gauss point stress extrapolation. Influence of fiber orientations, load parameters, fiber volume fractions, plate span to thickness ratios, aspect ratios, thickness of core and face, position of core, boundary conditions, environmental conditions and types of transverse loading in MATLAB R2015a environment are examined. The numerical results using present solution methodology are verified with the results available in the literatures.

scholarly journals Forced Vibration Analysis of Laminated Composite Shells Reinforced with Graphene Nanoplatelets Using Finite Element Method

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Trung Thanh Tran ◽  
Van Ke Tran ◽  
Pham Binh Le ◽  
Van Minh Phung ◽  
Van Thom Do ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Forced Vibration ◽  
Vibration Analysis ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Thermal Environments ◽  
Forced Vibration Analysis ◽  
Laminated Composite Shells ◽  
Element Method

This paper carries out forced vibration analysis of graphene nanoplatelet-reinforced composite laminated shells in thermal environments by employing the finite element method (FEM). Material properties including elastic modulus, specific gravity, and Poisson’s ratio are determined according to the Halpin–Tsai model. The first-order shear deformation theory (FSDT), which is based on the 8-node isoparametric element to establish the oscillation equation of shell structure, is employed in this work. We then code the computing program in the MATLAB application and examine the verification of convergence rate and reliability of the program by comparing the data of present work with those of other exact solutions. The effects of both geometric parameters and mechanical properties of materials on the forced vibration of the structure are investigated.

Natural Frequency of Laminated Composite Plates Using a Sinusoidal Theory

2014 ◽  
Vol 709 ◽  
pp. 148-152
Author(s):  
Guo Qing Zhou ◽  
Ji Wang ◽  
Song Xiang
Keyword(s):  
Differential Equations ◽  
Analytical Method ◽  
Deformation Theory ◽  
Natural Frequencies ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Simply Supported ◽  
Sinusoidal Shear Deformation Theory

Sinusoidal shear deformation theory is presented to analyze the natural frequencies of simply supported laminated composite plates. The governing differential equations based on sinusoidal theory are solved by a Navier-type analytical method. The present results are compared with the available published results which verify the accuracy of sinusoidal theory.

Study of hydrogenation and corrosion of steel equipment and pipelines at the production facilities of H2S -containing hydrocarbon raw materials

2021 ◽  
pp. 170-181
Author(s):  
R. K. Vagapov
Keyword(s):  
Raw Materials ◽  
Strength Properties ◽  
Point Of View ◽  
Low Alloy Steels ◽  
Safety And Reliability ◽  
Alloy Steels ◽  
Steel Equipment ◽  
Equipment And Pipelines ◽  
Corrosion Of Steel ◽  
The Impact

The impact of hydrogen sulfide raw materials on steel equipment and pipelines is associated not only with corrosion processes, but also with the hydrogenation of used carbon and low-alloy steels. This can lead to the loss of their strength properties and the subsequent destruction of equipment operated under conditions of increased operating pressures. Such corrosive-mechanical effects associated with the penetration of hydrogen into steel are the most dangerous from the point of view of the safety and reliability of the operation of facilities for the production of hydrocarbon fluids. The effect of H2S on the main types of structural steels was investigated according to the results of autoclave tests. The formation of blistering (blistering) and cracks on the surface of steels due to the effect of hydrogen on the steel was recorded. A study of the phase composition of corrosion products and their possible effect on the processes of corrosion and hydrogenation of steel has been carried out.

Free and forced vibration analysis of flyash/graphene filled laminated composite plates using higher order shear deformation theory

2021 ◽  
pp. 095440622110531
Author(s):  
Sarada P Parida ◽  
Pankaj C Jena
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Low Cost ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Weight Percentage ◽  
Circular Holes ◽  
Forced Vibration Analysis

The strength of the conventional composite plates can be enhanced by the use of additional fillers. These composite plates are often subjected to dynamic loading conditions which necessitate the study of their static and dynamic behavior. In this study, laminated composite plates (LCP) are fabricated by open layup process with epoxy as a base resin, E-glass fiber as reinforcement, and fillers: flyash and graphene. The fillers are included in order to improve the mechanical properties of the composite. The filler content in the composite is limited to 5% of the total volume. The weight percentage of fiber combined with fillers, treated as reinforcing constituents is limited to 60%. Graphene and flyash are added in different proportions to develop different kinds of LCPs. The free and forced vibrations of LCPs (using simple support end conditions) are measured by an indigenously developed low-cost vibration testing module. The experimental results have been used to validate the results obtained from the mathematical modeling by using fifth-order shear deformation theory and finite element approaches. Additionally, the effect of existing discontinuity in the LCP is studied. Circular holes of different dimensions at different locations are simulated in the numerical model and the consequences on modal frequencies are analyzed.

Thermal post-buckling of laminated and isotropic rectangular plates with fixed edges: Comparison of experimental and numerical results

2012 ◽  
Vol 226 (10) ◽  
pp. 2393-2401 ◽  
Author(s):  
Marco Amabili ◽  
Mohammad Reza Sareban Tajahmadi
Keyword(s):  
Deformation Theory ◽  
Laboratory Experiments ◽  
Continuation Method ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Numerical Results ◽  
Rectangular Plates ◽  
Arc Length ◽  
Thermal Changes ◽  
Post Buckling

Post-buckling behaviors of laminated composite and isotropic rectangular plates subjected to various thermal changes are studied. Geometric imperfections are taken into account since they play a fundamental role. The plate is modeled using a nonlinear, higher order shear deformation theory. Plates with clamped edges are considered. A pseudo-arc length continuation method is used to obtain numerical results. Laboratory experiments have been performed in order to compare to the numerical calculations.

scholarly journals The Prediction of Buckling Load of Laminated Composite Hat-Stiffened Panels Under Compressive Loading by Using of Neural Networks

2018 ◽  
Vol 12 (1) ◽  
pp. 468-480 ◽  
Author(s):  
Shashi Kumar ◽  
Rajesh Kumar ◽  
Sasankasekhar Mandal ◽  
Atul K. Rahul
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Network Architecture ◽  
Laminated Composite ◽  
Buckling Load ◽  
Stiffened Panel ◽  
Stiffness Ratio ◽  
Data Set ◽  
Stiffened Panels ◽  
Structural Problems

Background:Stiffened panels are being used as a lightweight structure in aerospace, marine engineering and retrofitting of building and bridge structure. In this paper, two efficient analytical computational tools, namely, Finite Element Analysis (FEA) and Artificial Neural Network (ANN) are used to analyze and compare the results of the laminated composite 750-hat-stiffened panels.Objective:Finite Element (FE) is an efficient and versatile method for the analysis of a complex problem. FE models have been used to generate data set of four different parameters. The four parameters are extensional stiffness ratio of skin in the longitudinal direction to the transverse direction, orthotropy ratio of the panel, the ratio of twisting stiffness to transverse flexural stiffness and smeared extensional stiffness ratio of stiffeners to that of the plate.Results and Conclusion:For training of ANN, multilayer feedforward back-propagation has been used as a network function with two-hidden layers in the neural network. The good network architecture is achieved after several iterations to predict the buckling load of the stiffened panel. ANN prediction for unknown new data set is in good agreement with FEA results of different cases, which show that ANN tool can be used for the design of complex structural problems in civil engineering and optimization of the laminated composite stiffened panel.

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