The dynamic stability of rectangular layered plates due to periodic in-plane load is studied in this paper. Using the finite strip method, the problem is reduced to that of one with finite degrees of freedom. Then following Bolotin's procedure, the regions of parametric instability have been determined. The influence of plate configuration, aspect ratio and static in-plane force have been studied. © 1986.

Perumal Chellapandi

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Dynamic stability of rectangular laminated composite plates

Computers and Structures

The dynamic instability of laminated composite cylindrical shells due to periodic loads is studied using a C0 shear flexible QUAD-9 shell element. The boundaries of the principal instability region are conveniently represented in the nondimensional excitation frequency-nondimensional load amplitude plane. The effects of various parameters such as ply-angle, number of layers, thickness and radius-to-side ratio on dynamic stability are brought out. © 1994.

Dynamic instability of laminated composite curved panels using finite element method

The problem of axisymmetric parametric stability of composite polar orthotropic circular and annular plates is analyzed, by using annular finite elements. The instability regions are found out by adopting Bolotin's procedure. Results of a detailed parametric study are reported for bilayered plates of clamped and simply supported boundaries, which show the effects of radii ratio, layer disposition etc., on the dynamic stability. © 1990.

Journal of Sound and Vibration

Axisymmetric parametric stability of composite annular plates

In this work, the primary and secondary instability region analysis of rotating multi-walled carbon nanotube (MWCNT) reinforced non-uniform hybrid composite plates (CNT-FRP) under uniaxial periodic loads is performed. First-order shear deformation theory has been used to derive the kinetic and potential energy equations of the various configurations of non-uniform composite plates by including the effect of rotary inertia, shear deformation, varying centrifugal stiffness and non-uniformity along the transverse direction of the plate. The governing differential equations of motion are derived in the form of Mathieu–Hill equations using the Hamilton’s principle. The efficacy of the developed finite-element formulation has been verified by comparing the natural frequencies of the rotating composite plates evaluated using the numerical simulation with the experimental results and available literature. This study also investigates the influence of the CNT vol%, CNT aspect ratio, angular rotation of plate and static load on the primary and secondary instability region of various non-uniform configurations of CNT-FRP hybrid composite plates. It was noticed that the primary and secondary regions of parametric instability of CNT-FRP hybrid composite plates shift upward when CNT vol% increases from 0 to 2%. It was further noticed that primary and secondary instability regions of various non-uniform configurations shift to the lower excitation frequency when MWCNT vol% increases beyond the saturation limit. It was observed that the effect of angular rotation and static load is significant on the primary and secondary regions of instability.

International Journal of Structural Stability and Dynamics

Primary and Secondary Instability Region Analysis of Rotating Carbon Nanotube–Reinforced Non-Uniform Hybrid Composite Plates

In this work, the dynamic instability analysis of a rotating CNT reinforced fiber reinforced polymer (CNTFRP) composite plate is performed under in-plane periodic loads. The elastic properties of CNTFRP composite plate are obtained using the modified Halpin-Tsai equations and the two phase micromechanical approach. The governing differential equations of motion of the rotating fiber reinforced polymer composite (FRP) plate without and with addition of CNT are derived in the finite element formulation using first order shear deformation (FSDT) by incorporating the effects of pre-stress induced stiffness and displacement-dependent stiffness due to steady state rotation. The validity of developed finite element model is studied by comparing the fundamental natural frequency and dynamic instability regions using present FEA with those available in literature. Various parametric studies are also performed to study the effect of CNT volume fraction and CNT aspect ratio on the dynamic instability regions of CNTFRPC plate. It was seen that the primary and secondary dynamic instability regions of the composite plate are significantly influenced by CNT volume fraction. © 2018 Author(s).

AIP Conference Proceedings

Numerical investigation of dynamic instability of a rotating CNT reinforced composite plate

In this study, the dynamic instability analysis of rotating delaminated thickness tapered composite plates with different taper configurations subjected to periodic in-plane loads is performed. The governing differential equations of motion of the various configurations of a rotating thickness mid-plane delaminated tapered laminated composite plate are presented in the finite element formulation based on classical laminated plate theory including various rotational effects. The finite element formulation developed for the dynamic instability analysis of rotating delaminated tapered composite plate is validated by comparing the parametric exciting frequencies evaluated using the present finite elementmethod (FEM) with those presented in available literature and comparing the natural frequencies of rotating delaminated tapered composite plate evaluated using the present FEM with experimentally measured results. Various parametric studies are also performed to study the effect of taper configurations, rotational speed, delamination length, delamination location and in-plane periodic loads on stability of the structure. It was seen that the influences of rotating speed on the principalDIR spectra among taper configurations and uniform plate are significant and the normalized width of principal and second instability regions of parametric resonance frequencies increase in the order of uniform, TC3, TC2 and TC1 for all the rotating speeds. © Springer-Verlag Berlin Heidelberg 2016.

Journal	Computers and Structures
ISSN	00457949
Open Access	No