scholarly journals Dynamic instability characteristics of laminated composite doubly curved panels subjected to partially distributed follower edge loading

2005 ◽  
Vol 42 (8) ◽  
pp. 2243-2264 ◽  
Author(s):  
L. Ravi Kumar ◽  
P.K. Datta ◽  
D.L. Prabhakara
Keyword(s):  
Dynamic Instability ◽  
Laminated Composite ◽  
Edge Loading ◽  
Doubly Curved ◽  
Curved Panels

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.

VIBRATION AND STABILITY BEHAVIOR OF LAMINATED COMPOSITE CURVED PANELS WITH CUTOUT UNDER PARTIAL IN-PLANE LOADS

2005 ◽  
Vol 05 (01) ◽  
pp. 75-94 ◽  
Author(s):  
L. RAVI KUMAR ◽  
P. K. DATTA ◽  
D. L. PRABHAKARA
Keyword(s):  
Dynamic Instability ◽  
Laminated Composite ◽  
Transverse Shear Deformation ◽  
Stability Behavior ◽  
Load Factors ◽  
Compressive Loads ◽  
Instability Regions ◽  
Doubly Curved ◽  
Curved Panels ◽  
Shear Deformable

The present paper is concerned with the vibration, buckling and dynamic instability behavior of laminated composite, cross-ply, doubly-curved panels with a central circular hole subjected to in-plane static and periodic compressive loads. A generalized shear deformable Sanders' theory is used to model the curved panels, considering the effects of transverse shear deformation and rotary inertia. Bolotin's approach is used for studying the dynamic instability regions of doubly-curved panels. The effects of non-uniform edge loads, curvature with different cutout ratios, static and dynamic load factors, and lamination parameters on curved panels are investigated with the results discussed.

Static and dynamic instability characteristics of curved laminates with internal damage subjected to follower loading

2011 ◽  
Vol 225 (7) ◽  
pp. 1589-1600 ◽  
Author(s):  
S Biswas ◽  
P K Datta ◽  
C D Kong
Keyword(s):  
Dynamic Instability ◽  
Shear Deformation Theory ◽  
Internal Damage ◽  
First Order ◽  
Static And Dynamic Instability ◽  
Element Approach ◽  
Formulation Analysis ◽  
Flutter Load ◽  
Doubly Curved ◽  
Curved Panels

This article deals with the study of vibration, buckling, and dynamic instability characteristics in damaged cross-ply and angle-ply curved laminates under uniform, uniaxial follower loading, using finite element approach. First-order shear deformation theory is used to model the doubly curved panels and is formulated according to Sandars' first approximation. Damage is modelled using an anisotropic damage formulation. Analysis is carried out on plate and three types of curved panels to obtain vibration, buckling, and dynamic instability (flutter) behaviour. The effect of damage on natural frequency, critical buckling load, flutter load, and flutter frequency is studied. The results show that the introduction of damage influences the flutter characteristics of panels more profoundly than the free-vibration or buckling characteristics. The results also indicate that, compared to undamaged panels, heavily damaged panels show steeper deviations in stability characteristics than mildly damaged ones.

Dynamic instability characteristics of doubly curved panels subjected to partially distributed follower edge loading with damping

2004 ◽  
Vol 218 (1) ◽  
pp. 67-81 ◽  
Author(s):  
L Ravi Kumar ◽  
P K Datta ◽  
D L Prabhakara
Keyword(s):  
Shear Deformation ◽  
Dynamic Instability ◽  
Shear Deformation Theory ◽  
Structural Damping ◽  
Element Analysis ◽  
Equivalent Viscous Damping ◽  
Direction Control ◽  
The Stability ◽  
Doubly Curved ◽  
Curved Panels

The vibration and dynamic instability characteristics of doubly curved panels subjected to partially distributed non-conservative follower load are studied using finite element analysis. The first-order shear deformation theory is used to model the doubly curved panels, considering the effects of shear deformation and rotary inertia. The theory used is the extension of dynamic, shear deformable theory according to Sander's first approximation for doubly curved shells, which can be reduced to Love's and Donnell's theories by means of tracers. The modal transformation technique is applied to the resulting equilibrium equation for subsequent analysis. Structural damping is introduced into the system in terms of equivalent viscous damping. The effects of load bandwidth, boundary condition, load direction control parameter and damping are considered for the stability behaviour of the panels. The results show that the load bandwidth has a significant effect on the dynamic instability characteristics of the panels. The analysis also shows that, under follower loading, the system is susceptible to instability due to flutter alone or due to both flutter and divergence, depending upon the system parameters. Structural damping significantly affects the critical flutter loads of the panels.

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