scholarly journals PARAMETRIC RESONANCE CHARACTERISTICS OF ANGLE-PLY TWISTED CURVED PANELS

2008 ◽  
Vol 08 (01) ◽  
pp. 61-76 ◽  
Author(s):  
S. K. SAHU ◽  
A. V. ASHA
Keyword(s):  
Shear Deformation ◽  
Dynamic Stability ◽  
Dynamic Instability ◽  
Excitation Frequency ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
First Order ◽  
Cylindrical Panels ◽  
Instability Regions ◽  
Curved Panels

The present study deals with the dynamic stability of laminated composite pre-twisted cantilever panels. The effects of various parameters on the principal instability regions are studied using Bolotin's approach and finite element method. The first-order shear deformation theory is used to model the twisted curved panels, considering the effects of transverse shear deformation and rotary inertia. The results on the dynamic stability studies of the laminated composite pre-twisted panels suggest that the onset of instability occurs earlier and the width of dynamic instability regions increase with introduction of twist in the panel. The instability occurs later for square than rectangular twisted panels. The onset of instability occurs later for pre-twisted cylindrical panels than the flat panels due to addition of curvature. However, the spherical pre-twisted panels show small increase of nondimensional excitation frequency.

PARAMETRIC COMBINATION RESONANCE CHARACTERISTICS OF DOUBLY CURVED PANELS SUBJECTED TO NON-UNIFORM HARMONIC EDGE LOADING

2005 ◽  
Vol 05 (04) ◽  
pp. 615-639 ◽  
Author(s):  
RATNAKAR S. UDAR ◽  
P. K. DATTA
Keyword(s):  
Shear Deformation ◽  
Dynamic Instability ◽  
Excitation Frequency ◽  
Instability Region ◽  
Load Factor ◽  
Combination Resonance ◽  
Edge Loading ◽  
Instability Regions ◽  
Doubly Curved ◽  
Curved Panels

This paper is concerned with the problem of occurrence of combination resonances in parametrically excited doubly curved panels. The dynamic instability of doubly curved panels, subjected to non-uniform in-plane harmonic loading is investigated. Sander's first-order shear deformation theory is used to model the doubly curved panels, considering the effects of transverse shear deformation and rotary inertia. The theory can be reduced to Love's and Donnell's theories by means of tracers. Analytical expressions for the instability regions are obtained at Ω = ωm+ ωn(Ω is the excitation frequency and ωmand ωnare the natural frequencies of the system), by using the method of multiple scales. It is shown that besides the principal instability region at Ω =2ω1, where ω1is the fundamental frequency, other cases of Ω = ωm+ ωnwhich are related to other modes, can be of major importance and yield a significantly enlarged instability region. The results show that under localized edge loading, combination resonance zones are as important as simple resonance zones. The effects of edge loading, curvature, shallowness ratio, edge length to thickness ratio, aspect ratio, boundary conditions and the static load factor on dynamic instability regions are considered.

PARAMETRIC INSTABILITY OF LAMINATED COMPOSITE CYLINDRICAL PANELS SUBJECTED TO PERIODIC NON-UNIFORM IN-PLANE LOADS

2011 ◽  
Vol 03 (04) ◽  
pp. 845-865 ◽  
Author(s):  
SARAT KUMAR PANDA ◽  
L. S. RAMACHANDRA
Keyword(s):  
Differential Equations ◽  
Dynamic Instability ◽  
Elastic Shell ◽  
Parametric Instability ◽  
Shear Deformation Theory ◽  
Mathieu Equation ◽  
Laminated Composite ◽  
Stress Distributions ◽  
Cylindrical Panels ◽  
Instability Regions

In the present investigation, the dynamic instability regions of shear deformable cross-ply laminated and composite cylindrical panels subjected to periodic nonuniform in-plane loads are reported. Since the applied in-plane load is nonuniform, initially the static part of the nonuniform in-plane loads are applied and the stresses (σx, σy and τxy) within the panel are evaluated by the solution of cylindrical panel membrane problem. Subsequently, superposing the stress distribution due to static and dynamic in-plane loads, the stress distributions within the panel are obtained. Using these stress distributions the governing equations of the problem are derived through Hamilton's variational principle based on higher-order shear deformation theory of elastic shell theory incorporating von Kármán-type nonlinear strain displacement relations. The governing partial differential equations are reduced into a set of ordinary differential equations (Mathieu-type of equations) by employing Galerkin's method. The instability boundaries of Mathieu equation corresponding to periodic solutions of period T and 2T are determined using Fourier series. Effect of various parameters like static and dynamic load factors, aspect ratio, thickness-to-radius ratio, shallowness ratio, linearly varying in-plane load, parabolic in-plane load and various boundary conditions on the instability regions are investigated.

Dynamic Instability of Laminated-Composite and Sandwich Plates Using a New Inverse Trigonometric Zigzag Theory

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Rosalin Sahoo ◽  
B. N. Singh
Keyword(s):  
Stability Analysis ◽  
Boundary Conditions ◽  
Dynamic Stability ◽  
Dynamic Instability ◽  
Excitation Frequency ◽  
Laminated Composite ◽  
Sandwich Plates ◽  
Load Amplitude ◽  
Instability Regions ◽  
Zigzag Theory

A structure with periodic dynamic load may lead to dynamic instability due to parametric resonance. In the present work, the dynamic stability analysis of laminated composite and sandwich plate due to in-plane periodic loads is studied based on recently developed inverse trigonometric zigzag theory (ITZZT). Transverse shear stress continuity at layer interfaces along with traction-free boundary conditions on the plate surfaces is satisfied by the model obviating the need of shear correction factor. An efficient C0 continuous, eight noded isoparametric element with seven field variable is employed for the dynamic stability analysis of laminated composite and sandwich plates. The boundaries of instability regions are determined using Bolotin's approach and the first instability zone is presented either in the nondimensional load amplitude–excitation frequency plane or load amplitude–load frequency plane. The influences of various parameters such as degrees of orthotropy, span-thickness ratios, boundary conditions, static load factors, and thickness ratios on the dynamic instability regions (DIRs) are studied by solving a number of problems. The evaluated results are validated with the available results in the literature based on different deformation theories. The efficiency of the present model is ascertained by the improved accuracy of predicted results at the cost of less computational involvement.

Dynamic instability of laminated composite rectangular plates subjected to non-uniform harmonic in-plane edge loading

2000 ◽  
Vol 214 (5) ◽  
pp. 295-312 ◽  
Author(s):  
S K Sahu ◽  
P K Datta
Keyword(s):  
Shear Deformation ◽  
Composite Laminates ◽  
Dynamic Instability ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Geometrical Parameters ◽  
Rectangular Plates ◽  
Element Analysis ◽  
Instability Regions

The dynamic instability behaviour of isotropic, cross-ply and angle-ply laminated composite plates under combined uniaxial and harmonically varying in-plane point or patch loads is investigated using finite element analysis. The first-order shear deformation theory is used to model the composite laminates, considering the effects of transverse shear deformation and rotary inertia. The effects of various geometrical parameters, boundary conditions, lamination and load parameters on the principal dynamic instability regions of composite plates are studied in detail. The preferential orientations depending on the instability regions for simply supported patch and point loaded plates have been suggested for angle-ply plates. The dynamic instability region has been influenced by the restraint provided at the edges.

The influences of magnetostrictive layers on active vibration control of laminated composite rotating cylindrical shells based on first-order shear deformation theory

2019 ◽  
Vol 233 (13) ◽  
pp. 4606-4619 ◽  
Author(s):  
Shahin Mohammadrezazadeh ◽  
Ali Asghar Jafari
Keyword(s):  
Vibration Control ◽  
Shear Deformation ◽  
Deformation Theory ◽  
Cylindrical Shells ◽  
Active Vibration Control ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
First Order ◽  
Vibration Responses ◽  
Active Vibration

In this paper for the first time, active vibration control of rotating laminated composite cylindrical shells embedded with magnetostrictive layers as actuators by means of first-order shear deformation theory is studied. Vibration equations of the rotating shell are extracted using Hamilton principle considering the effects of initial hoop tension, Coriolis, and centrifugal forces. The vibration differential equations are reduced to algebraic ones through Galerkin method. The validity of the study is proved by the comparison of some results with the literature results. Eventually, the influence of several parameters on damping characteristics and vibration responses are investigated in detail.

THERMAL BUCKLING OF CLAMPED CYLINDRICAL PANELS BASED ON FIRST-ORDER SHEAR DEFORMATION THEORY

2004 ◽  
Vol 04 (03) ◽  
pp. 313-336 ◽  
Author(s):  
ABDULLATEEF M. AL-KHALEEFI
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Analytical Approach ◽  
Solution Method ◽  
Shear Deformation Theory ◽  
Cylindrical Panel ◽  
Thermal Buckling ◽  
First Order ◽  
Cylindrical Panels ◽  
Dimensional Parameters

Based on the first-order shear deformation shell theory, an analytical approach is developed to predict the thermal buckling response of an all-edge clamped cylindrical panel. The analytical approach adopts a double Fourier solution method suitable for cylindrical panels. The present solutions are compared with the finite element solutions obtained using ANSYS. The effects of various dimensional parameters are included in the study.

A Simple Higher-Order Theory for Laminated Composite Plates

1984 ◽  
Vol 51 (4) ◽  
pp. 745-752 ◽  
Author(s):  
J. N. Reddy
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Order Theory ◽  
Higher Order ◽  
Laminated Composite Plates ◽  
First Order ◽  
First Order Theory

A higher-order shear deformation theory of laminated composite plates is developed. The theory contains the same dependent unknowns as in the first-order shear deformation theory of Whitney and Pagano [6], but accounts for parabolic distribution of the transverse shear strains through the thickness of the plate. Exact closed-form solutions of symmetric cross-ply laminates are obtained and the results are compared with three-dimensional elasticity solutions and first-order shear deformation theory solutions. The present theory predicts the deflections and stresses more accurately when compared to the first-order theory.

A novel first-order shear deformation theory for laminated composite plates

2014 ◽  
Vol 17 (3) ◽  
pp. 321-338 ◽  
Author(s):  
Mohamed Sadoune ◽  
Abdelouahed Tounsi ◽  
Mohammed Sid Ahmed Houari ◽  
El Abbes Adda Bedia
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
First Order
Sign in / Sign up

Export Citation Format

Share Document