The Dynamics Research Group (DRG) based in the Department of Mechanical Engineering at the University ofSheffield conducts research into vibrations and the dynamics of structures. The main areas of research are:nonlinear dynamics, structural health monitoring, active and passive vibration control, smart materials andstructures and acoustics.In the field of nonlinear dynamics, th...

Joined-wing aircraft are being designed for ‘sensorcraft’ configuration. Joined wings lead to multiple load paths and constraints. The focus of this work is to understand the nonlinear structural as well as aeroelastic behavior of joined wings. The paper presents a formulation for the nonlinear aeroelastic analysis of joined wings. Results are presented for two joined wings configurations. Over...

We demonstrate that stable nonlinear localized modes can exist not only at a light-mass isotopic impurity, but also at a heavy-mass impurity, due to an interplay between discreteness and nonlinearity. This is in sharp contrast to the theory of linear lattice vibrations that an impurity mode is possible only at a light-mass defect. We determine the structure of the nonlinear impurity modes analy...

  ABSTRACT: A prismatic beam made of a behaviorally nonlinear material situated on nonlinear elastic foundation is analyzed under a moving harmonic load moving with a known velocity. The vibration equation of motion    is derived using Hamilton principle and Euler Lagrange equation. The amplitude of vibration, circular frequency, bending moment, stress and deflection of the beam can be calculat...

Abstract  In this paper , the nonlinear the nonlinear free and forced axisymmetric vibration of a thin circular functionally graded plate with rigid core is formulated in terms of von-Karman’s dynamic equation , and a semi-analytical approach is developed.Functionally graded material (FGM) properties vary through the thickness of the plate.FGM s are spatial composites within which material prop...

In this study, a hybrid method is proposed to investigate the nonlinear vibrations of pre- and post-buckled rectangular plates for the first time. This is an answer to an existing need to develope a fast and precise numerical model which can handle the nonlinear vibrations of buckled plates under different boundary conditions and plate shapes. The method uses the differential quadrature element...

The aim of this paper is to conduct experimental modal analysis and numerical simulation to verify the structural characteristics of a deployable-retractable wing for aircraft and spacecraft. A modal impact test was conducted in order to determine the free vibration characteristics. Natural frequencies and vibration mode shapes were obtained via measurement in LMS Test. Lab. The frequency respo...

This study investigates the response frequency conversion characteristic of a nonlinear curved panel mounted with a centre mass and the sound radiations. A set of coupled governing differential equations is set up and used to generate the nonlinear vibration responses, which are used to calculate the corresponding radiated sounds. The vibration, sound levels, and the ratio of the antisymmetrica...

With appropriate vibration modeling and analysis the incipient failure of key components such as the tower, drive train and rotor of a large wind turbine can be detected. In this paper, the Nonlinear State Estimation Technique (NSET) has been applied to model turbine tower vibration to good effect, providing an understanding of the tower vibration dynamic characteristics and the main factors in...