Department of Mechanical Engineering
The performance of engineering structures is governed by how well they behave in their operating environment. For a significant number of engineering sectors, such as wind/wave power generation, automotive, medical robotics, aerospace and large civil infrastructure, dynamic effects dominate the operational regime. As a result, understanding structural dynamics is crucial for ensuring that we have safe, reliable and efficient structures.
My research is focused on understanding and controlling nonlinear structural dynamics. Nonlinearity occurs quite naturally in many applications, but despite this it has traditionally been avoided in the design of engineering systems. However, the performance envelope for all engineering structures is being pushed in response to the urgent societal need to find technological solutions for global issues such as climate change, and as a result understanding and controlling nonlinearity is becoming increasingly important in many engineering applications. A current topical example is the dynamics of large wind turbines.
My current research activities includes both fundamental and applied work on topics such as; nonlinear resonance, semi-active damping, and morphing structures. Some of this relates to, so called, smart technologies, where control and feedback are used to give some form of "intelligent" behaviour to the structure. Other related work includes active vibration control, energy harvesting and energy efficient structures. Much of my research includes experimental testing
and, in particular I have been involved in new developments of hybrid testing
such as hardware-in-the-loop and real-time dynamic substructuring. This has
particularly useful application in testing for large structures, such as bridges,
and other seismically excited structures.
Areas of Research
-Nonlinear dynamics of flexible structures
-Vibration suppression and isolation systems
-Dynamics of composite materials
-Experimental testing and measurement for nonlinear dynamics
-Structural control techniques
Recent research achievements:
-New £4.2M EPSRC programme grant on Engineering Nonlinearity. See also the News from EPSRC and the University of Bristol news.
-My co-edited book: Exploiting Nonlinear Behaviour in Structural Dynamics is available from Amazon here.
-EPSRC grant awarded on Low power control methods for energy efficient structures.
-A Colloquium on Structural Control and Energy Harvesting took place in Bristol from 25-27 July 2011.
-A lecture course on Exploiting Nonlinear Behaviour in Structural Dynamics took place 13-17 September, 2010, hosted by the International Centre for Mechanical Sciences.
-My co-authored book: Nonlinear Vibration with Control is available from Amazon here.
-Work on controlling spinning pendulum motions using experimental continuation was reported in Physical Review Focus.
-I organised a workshop on adaptive structures, which took place in Bristol in July 2006. The proceedings are available from Amazon now.
-From 2004-2009 I was as EPSRC Advanced Research Fellow on the dynamics and control of hybrid systems with applications to real-time dynamic substructuring. Details of all my EPSRC grants can be found here.
Funded PhD opportunities are often available and I am always interested to hear from potential PhD students. You will need a first class (or equivalent) degree in engineering or a related subject such as Mathematics or Physics. Post-doctoral opportunities are usually advertised on http://www.jobs.ac.uk/. I'm am also happy to consider applications for short visits (typically up to one year) such as those funded by the China Scholarship Council.
Gawthrop, PJ and Neild, SA and Wagg, DJ (2012) Semi-active damping using a hybrid control approach. Journal of Intelligent Material Systems and Structures. 23(18), 2103-2116.
Shaw, AD and Neild, SA and Wagg, DJ (2012) Dynamic analysis of high static low dynamic stiffness vibration isolation mounts. Journal of Sound and Vibration. 332, 1437-1455.
Neild SA and Wagg DJ (2011) Applying the method of normal forms to second-order nonlinear vibration problems. Proceedings of the Royal Society of London A. 467, 1141-1163.
Arrieta AF, Wagg DJ and Neild SA (2011) Dynamic Snap-through for Morphing of Bi-stable Composite Plates Journal of Intelligent Material Systems and Structures 22(2), 103-112.
Macdonald JHG, Dietz MS, Neild SA, Gonzalez-Buelga A, Crewe AJ, Wagg DJ (2010) Generalised modal stability of inclined cables subjected to support excitations Journal of Sound and Vibration 329(21), 4515-4533.
Potter JN, Neild SA, Wagg DJ (2010) Generalisation and optimisation of semi-active, on-off switching controllers for single degree-of-freedom systems. Journal of Sound and Vibration. 329, 2450-2462.
Arrieta AF, Wagg DJ and Neild SA (2009) Nonlinear dynamics of a bi-stable composite laminate plate with applications to adaptive structures. Nonlinear Dynamics 58, 259-272.
Gawthrop PJ, Virden DW, Neild SA and Wagg DJ (2008) Emulator-based control for actuator-based hardware-in-the-loop testing. Control Engineering Practice 16(8), 897-908.
Gonzalez-Buelga A, Neild SA, Wagg DJ andMacdonald JHG (2008) Modal stability of inclined cables subjected to vertical support excitation Journal of Sound and Vibration 318(3), 565-579.
Sieber J, Gonzalez-Buelga A, Neild SA, Wagg DJ and Krauskopf B (2008) Experimental continuation of periodic orbits through a fold. Physical Review Letters 100, 244101.
Gonzalez-Buelga A, Wagg DJ and Neild SA (2007) Parametric variation of a coupled pendulum-oscillator system using real-time dynamic substructuring. Structural Control and Health Monitoring. 14(7), 991-1012.
Kyrychko YN, Hogan SJ, Gonzalez-Buelga A, Wagg DJ (2007) Modelling real-time dynamic substructuring using partial delay differential equations. Proceedings of the Royal Society of London A. 463(2082), 1509-1523.
Kyrychko YN, Blyuss KB, Gonzalez-Buelga A, Hogan SJ, Wagg DJ (2006) Real-time dynamic substructuring in a coupled oscillator-pendulum system. Proceedings of the Royal Society of London A. 462(2068), 1271-1294.
Wallace MI, Sieber J, Neild SA, Wagg DJ and Krauskopf B (2005) Stability analysis of real-time dynamic substructuring using delay differential equation models. Earthquake Engineering and Structural Dynamics 34(15), 1817-1832.
Wallace MI, Wagg DJ and Neild SA (2005) An adaptive polynomial based forward prediction algorithm for multi-actuator real-time dynamic substructuring. Proceedings of the Royal Society of London A 461(2064), 3807-3826.
Wagg DJ and Bishop SR (2004) Dynamics of a two degree of freedom vibro-impact system with multiple motion limiting constraints International Journal of Bifurcation and Chaos 14(1), 119-140.
Wagg DJ (2003) Adaptive control of nonlinear dynamical systems using a model reference approach Meccanica 38 (2), 227-238.
Wagg DJ and Bishop SR (2002) Application of nonsmooth modelling techniques to the dynamics of a flexible impacting beam. Journal of Sound and Vibration 256(5), 803-820.
Wagg DJ and Stoten DP (2001) Substructuring of dynamical systems via the adaptive minimal control synthesis algorithm. Earthquake Engineering and Structural Dynamics 30, 865-877.
Wagg DJ and Bishop SR (2000) A note on modelling multi-degree-of-freedom vibro-impact systems using coefficient of restitution models Journal of Sound and Vibration 236(1), 176-184.
Wagg DJ, Karpodinis G and Bishop SR (1999). An experimental study of the impulse response of a vibro-impacting cantilever beam. Journal of Sound and Vibration 228(2), 243-264.
A more complete list of publications can be found here.