Boundary Condition Effects on the Parametric Stability of Moderately Thick Laminated Cylindrical Panels

2011 ◽  
Vol 471-472 ◽  
pp. 466-471 ◽  
Author(s):  
Jamshid Fazilati ◽  
Hamid Reza Ovesy
Keyword(s):  
Shear Deformation Theory ◽  
Parametric Stability ◽  
Third Order ◽  
Shallow Shells ◽  
Finite Strip ◽  
Finite Strip Method ◽  
Stability And Instability ◽  
Laminated Panels ◽  
The Subject ◽  
Instability Regions

A Reddy type, third order shear deformation theory of shells is applied to the development of two versions of finite strip method (FSM), namely semi-analytical and spline methods, to predict the parametric stability and instability regions in the case of cylindrical moderately thick composite laminated panels. The structures are assumed to be under harmonic in-plane loads in the context of the so-called parametric loading. The linear strain terms are expressed in terms of the Koiter-Sanders theory of shallow shells. In order to demonstrate the capabilities of the developed methods in predicting parametric behavior of the subject structures, some representative results are obtained and compared with those in the literature wherever available.

A Semi-Energy Finite Strip Method for Post-Buckling Analysis of Relatively Thick Anti-Symmetric Cross-Ply Laminates

2011 ◽  
Vol 471-472 ◽  
pp. 426-431 ◽  
Author(s):  
Mohammad Hajikazemi ◽  
Hamid Reza Ovesy ◽  
Mohammad Homayoun Sadr-Lahidjani
Keyword(s):  
Closed Form Solution ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Form Solution ◽  
Laminated Plates ◽  
Plane Boundary ◽  
Finite Strip ◽  
Strip Method ◽  
Finite Strip Method ◽  
Post Buckling

In the current paper, a new semi-energy finite strip method is developed based on the concept of first order shear deformation theory (FSDT) in order to attempt the post-buckling solution for relatively thick composite plates subjected to uniform end-shortening. The main advantage of the semi-energy finite strip method (FSM) is that it is based on the closed form solution of von Karman’s compatibility equation in order to derive the analytical shape functions for the in-plane displacements fields. The developed finite strip method is applied to analyze the post buckling behavior of a relatively thick anti-symmetric cross-ply composite plate with clamped out-of-plane boundary conditions at its loaded ends. The results are discussed in detail and compared with those obtained from finite element method (FEM) of analysis. The study of the results has provided confidence in the validity and capability of the developed finite strip in handling post-buckling problem of relatively thick laminated plates.

A third-order shear deformation theory for nonlinear vibration analysis of stiffened functionally graded material sandwich doubly curved shallow shells with four material models

2017 ◽  
Vol 21 (4) ◽  
pp. 1316-1356 ◽  
Author(s):  
Dang T Dong ◽  
Dao Van Dung
Keyword(s):  
Functionally Graded Material ◽  
Vibration Analysis ◽  
Deformation Theory ◽  
Natural Frequencies ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Third Order ◽  
Shallow Shells ◽  
Graded Material ◽  
Doubly Curved

This study presents a nonlinear vibration analysis of function graded sandwich doubly curved shallow shells, which reinforced by functionally graded material stiffeners and rested on the Pasternak foundation. The shells are subjected to the combination of mechanical, thermal, and damping loading. Four models of the sandwich shells with general sigmoid and power laws distribution are considered. The governing equations are established based on the third-order shear deformation theory. Von Kármán-type nonlinearity and smeared stiffener technique are taken into account. The explicit expressions for determining natural frequencies, nonlinear frequency–amplitude relation, and time–deflection curves are obtained by employing the Galerkin method. Finally, the fourth-order Runge–Kutta method is applied to investigate the influences of functionally graded material stiffeners, the boundary conditions, the models of the shells, thermal environment, foundation and geometrical parameters on the natural frequencies and dynamic nonlinear responses of the sandwich shells.

Dynamic Stability of Woven Fiber Laminated Composite Shallow Shells in Hygrothermal Environment

2017 ◽  
Vol 17 (08) ◽  
pp. 1750084 ◽  
Author(s):  
M. Biswal ◽  
S. K. Sahu ◽  
A. V. Asha
Keyword(s):  
Dynamic Stability ◽  
Degrees Of Freedom ◽  
Dynamic Instability ◽  
Shear Deformation Theory ◽  
Shell Element ◽  
Load Factor ◽  
Element Formulation ◽  
Shallow Shells ◽  
Instability Regions ◽  
Hygrothermal Environment

The dynamic stability of bidirectional woven fiber laminated glass/epoxy composite shallow shells subjected to harmonic in-plane loading in hygrothermal environment is considered. An eight-noded isoparametric shell element with five degrees of freedom is used in the analysis. In the present finite element formulation, a composite doubly curved shell model based on first-order shear deformation theory (FSDT) is used for the dynamic stability analysis of shell panels subjected to hygrothermal loading. A program is developed using MATLAB for the parametric study on the dynamic stability of shell panels under the hygrothermal field. The effects of various parameters like static load factor, curvature, shallowness, temperature, moisture, stacking sequence and boundary conditions on the dynamic instability regions of woven fiber glass/epoxy shell panels are investigated. The location of dynamic instability regions is shown to affect significantly due to presence of the hygrothermal field.

Lay-Up Effects on the Dynamic Instability of Moderately Thick Stiffened Curved Panels

2012 ◽  
Vol 152-154 ◽  
pp. 1477-1482
Author(s):  
Hamid Reza Ovesy ◽  
Jamshid Fazilati
Keyword(s):  
Cylindrical Shell ◽  
Shear Deformation ◽  
Dynamic Instability ◽  
Third Order ◽  
Longitudinal Stiffener ◽  
Finite Strip ◽  
The Third ◽  
Strip Method ◽  
Finite Strip Method ◽  
Curved Panels

The dynamic instability of cylindrical shell panels having longitudinal stiffener is studied by using the developed finite strip method (FSM). The method is formulated using the third order shear deformation shell's theory of Reddy's form and the Koiter-Sanders theory for cylindrical shells is implemented. The lay-up effects of skin as well as the stiffener are investigated.

Bending analysis of functionally graded sandwich plates using the refined finite strip method

2021 ◽  
pp. 109963622110204
Author(s):  
Mohammad Naghavi ◽  
Saeid Sarrami-Foroushani ◽  
Fatemeh Azhari
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Sandwich Plate ◽  
Plate Theory ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Sandwich Plates ◽  
Finite Strip ◽  
Strip Method ◽  
Finite Strip Method

In this study, static analysis of functionally graded (FG) sandwich plates is performed using the finite strip method based on the refined plate theory (RPT). Two types of common FG sandwich plates are considered. The first sandwich plate is composed of two FG material (FGM) face sheets and a homogeneous ceramic or metal core. The second one consists of two homogeneous fully metal and ceramic face sheets at the top and bottom, respectively, and a FGM core. Differential equations of FG sandwich plates are obtained using Hamilton's principle and stiffness and force matrices are formed using the finite strip method. The central deflection and the normal stress values are obtained for a sinusoidal loaded FG sandwich plate and the accuracy of the results are verified against those obtained from other theories such as the classical plate theory (CPT), the first-order shear deformation theory (FSDT), and the higher order shear deformation theory (HSDT). For the first time, this study presents a finite strip formulation in conjunction with the RPT to analyze FG Sandwich plates. While the proposed method is fast and simple, it is capable of modeling a variety of boundary conditions.

scholarly journals Experimental Optical Testing and Numerical Verification by CuFSM of Compression Columns with Modified Channel Sections

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1271
Author(s):  
Piotr Paczos ◽  
Aleksandra M. Pawlak
Keyword(s):  
Cross Section ◽  
Compressive Force ◽  
Experimental Tests ◽  
Numerical Verification ◽  
Buckling Modes ◽  
Strain Gauging ◽  
Finite Strip ◽  
Finite Strip Method ◽  
Walled Channel ◽  
The Subject

Thin-walled channel columns with non-standard cross-section shapes loaded with gradually increasing compressive force applied at the geometric centre of gravity of the cross-section were the subject of the investigations presented in this paper. The aim of the research was to determine which of the columns has the most favourable geometrical characteristics in terms of the applied load. The main investigation was an experimental study carried out using two methods: strain gauging and the optical method. Based on strain gauging, the critical forces were determined using the strain averaging method and the linear regression tangent to compression plot method. In addition, modern optical tests were performed using the ARAMIS system. The buckling forces at which the first signs of buckling appear and the buckling modes of columns were determined. The results obtained from the experimental tests were used to validate the results of numerical tests carried out using the Finite Strip Method (CuFSM). Based on this method, the values of critical forces and the percentage contribution of individual buckling forms to the loss of stability of the compressed columns were determined.

Thermal Buckling Analysis of Moderately Thick Plates Using Functionally Graded Strips

2011 ◽  
Vol 471-472 ◽  
pp. 757-762
Author(s):  
Mohammad Nassirnia ◽  
Hamid Reza Ovesy ◽  
Seyyed Amir Mahdi Ghannadpour
Keyword(s):  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Power Law Distribution ◽  
Simply Supported ◽  
Finite Strip ◽  
Finite Strip Method ◽  
Total Potential ◽  
Nonlinear Temperature ◽  
Functionally Graded Strip ◽  
Moderately Thick Plates

In the current study, the critical buckling of functionally graded plates (FGPs) subjected to thermal loads is evaluated using the finite strip method based on the first order shear deformation theory (FSDT). The material properties of these plates are assumed to vary in the thickness direction of the plate according to the power law distribution in terms of volume fractions of the constituents. The plates’ boundary conditions are assumed to be simply supported in all the edges or clamped in side edges and simply supported on the ends. The fundamental eigen-buckling equations for the plates are obtained by discretizing the plate into some strips, called functionally graded strip (FGS). The solution is obtained by the minimization of the total potential energy as well as solving the eigenvalue problem. The effects of material gradient index, aspect ratio and different thermal loadings (i.e. uniform temperature rise and nonlinear temperature change across the thickness) on the critical buckling temperature difference will be presented in some graphical forms.

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