Dynamic Design Tools For Understanding and Exploiting Nonlinearity in Structures
Lead Research Organisation:
University of Bristol
Department Name: Mechanical Engineering
Abstract
The dynamic behaviour of mechanical systems and structures is often critical to their performance. Examples where unpredicted dynamic behaviour has resulted in poor performance include the London Millennium Footbridge prior to retrofitting with dampers and wheel shimmy experienced in aircraft landing gear and motorbikes.
When structures remain in their linear operating region, where the response is proportional to the size of the force causing it, there are well-established modelling and experimental validation tools for analysing their dynamic behaviour. If the structure exceeds the linear operating region and starts to exhibit nonlinear behaviour, for example due to large deflections, the effectiveness of these tools rapidly reduces leading to high degrees of design uncertainty. This uncertainty leads to multiple design iterations and increased costly experimental validation and even the discovery of undesirable behaviour late in the design process resulting in significant delay and additional expense.
This presents a problem when trying to innovate to improve performance, for example by reducing weight or using new materials, as this tends to add nonlinear effects. Currently the consequence of the limitations in existing tools is that the resulting uncertainty is compensated for by conservative design. What are urgently needed are design tools that can cope with complex nonlinear behaviour. The new nonlinear design tools this research will provide will greatly reduced the costs associated with designing new high performance products. Such step changes to the UK's capability for advanced design will assist high-end manufacturing industry to maintain its competitive edge.
When structures remain in their linear operating region, where the response is proportional to the size of the force causing it, there are well-established modelling and experimental validation tools for analysing their dynamic behaviour. If the structure exceeds the linear operating region and starts to exhibit nonlinear behaviour, for example due to large deflections, the effectiveness of these tools rapidly reduces leading to high degrees of design uncertainty. This uncertainty leads to multiple design iterations and increased costly experimental validation and even the discovery of undesirable behaviour late in the design process resulting in significant delay and additional expense.
This presents a problem when trying to innovate to improve performance, for example by reducing weight or using new materials, as this tends to add nonlinear effects. Currently the consequence of the limitations in existing tools is that the resulting uncertainty is compensated for by conservative design. What are urgently needed are design tools that can cope with complex nonlinear behaviour. The new nonlinear design tools this research will provide will greatly reduced the costs associated with designing new high performance products. Such step changes to the UK's capability for advanced design will assist high-end manufacturing industry to maintain its competitive edge.
Planned Impact
The design tools proposed here will provide a means of analysing and validating the response of structures with nonlinearities. Currently it is normal practice to design structures such that they operate in their linear response regime. However this often leads to over-restrictive design resulting in, for example, stiffer and hence heavier structures that in an aerospace context would lead to reduced fuel efficiency. The tools that will be developed during this fellowship will remove the conservative linear design constraint. This will allow, for example, more efficient light-weight structures resulting in better energy efficiency and reductions in material used so reducing pressures on resources and benefiting the environment.
The new tools will make a major step toward reducing the high levels of uncertainty associated with the presence of nonlinear effects. The current uncertainty leads to multiple design iterations and increased costly experimental validation and even the discovery of undesirable dynamic behaviour late in the design process resulting in delay and additional expense. For example, full-scale testing of an aircraft engine can cost in the order of £1million a day at the end of a design cycle whereas tests much earlier in the process cost two or even three orders of magnitude less. The reduced uncertainty the new tools will provide will greatly reduce the costs associated with designing new high performance products. Such step changes to the UK's capability for advanced design will assist the UK high-end manufacturing industry to maintain its competitive edge in the face of increasing competition from around the world.
The key outcomes from the fellowship will be the software-implemented tools for nonlinear dynamic design of structures. To maximise its impact every effort will be made to ensure that these tools can be used for industrial applications without requiring expert knowledge of the fundamental research and so providing an out-of-the-box analysis method.
The new tools will make a major step toward reducing the high levels of uncertainty associated with the presence of nonlinear effects. The current uncertainty leads to multiple design iterations and increased costly experimental validation and even the discovery of undesirable dynamic behaviour late in the design process resulting in delay and additional expense. For example, full-scale testing of an aircraft engine can cost in the order of £1million a day at the end of a design cycle whereas tests much earlier in the process cost two or even three orders of magnitude less. The reduced uncertainty the new tools will provide will greatly reduce the costs associated with designing new high performance products. Such step changes to the UK's capability for advanced design will assist the UK high-end manufacturing industry to maintain its competitive edge in the face of increasing competition from around the world.
The key outcomes from the fellowship will be the software-implemented tools for nonlinear dynamic design of structures. To maximise its impact every effort will be made to ensure that these tools can be used for industrial applications without requiring expert knowledge of the fundamental research and so providing an out-of-the-box analysis method.
People |
ORCID iD |
| Simon Neild (Principal Investigator / Fellow) |
Publications
A. Cammarano
(2014)
Non-unison resonant vibrations in nonlinear systems
in ISMA2014
A.D. Shaw
(2014)
Nonlinear vibration isolators with static loading errors and asymmetric stiffness
in ISMA2014
Araujo-Estrada S
(2016)
Wind Tunnel Manoeuvre Rig: A Multi-DOF Test Platform for Model Aircraft
Araujo-Estrada S
(2022)
Capturing nonlinear time-dependent aircraft dynamics using a wind tunnel manoeuvre rig
in Aerospace Science and Technology
Calderon D
(2019)
Sizing High-Aspect-Ratio Wings with a Geometrically Nonlinear Beam Model
in Journal of Aircraft
Cammarano A
(2014)
Bifurcations of backbone curves for systems of coupled nonlinear two mass oscillator
in Nonlinear Dynamics
Cammarano A
(2014)
The bandwidth of optimized nonlinear vibration-based energy harvesters
in Smart Materials and Structures
Cammarano A
(2014)
Optimum resistive loads for vibration-based electromagnetic energy harvesters with a stiffening nonlinearity
in Journal of Intelligent Material Systems and Structures
Cook R
(2020)
Industrially Inspired Gust Loads Analysis of Various-Aspect-Ratio Wings Featuring Geometric Nonlinearity
in Journal of Aircraft
Eaton A
(2018)
Numerical Continuation of Limit Cycle Oscillations and Bifurcations in High-Aspect-Ratio Wings
in Aerospace
Ehrhardt D
(2019)
Experimentally measuring an isolated branch of Nonlinear normal modes
in Journal of Sound and Vibration
Ehrhardt D
(2018)
Veering and nonlinear interactions of a clamped beam in bending and torsion
in Journal of Sound and Vibration
Elliott A
(2019)
Using frequency detuning to compare analytical approximations for forced responses
in Nonlinear Dynamics
Elliott AJ
(2018)
Comparing the direct normal form and multiple scales methods through frequency detuning.
in Nonlinear dynamics
Gawthrop P
(2014)
Dynamically dual vibration absorbers: a bond graph approach to vibration control
in Systems Science & Control Engineering
Gill S
(2016)
Impact of Controller Delays on the Nonlinear Dynamics of Remotely Piloted Aircraft
in Journal of Guidance, Control, and Dynamics
Gill S
(2015)
Nonlinear Dynamics of Aircraft Controller Characteristics Outside the Standard Flight Envelope
in Journal of Guidance, Control, and Dynamics
Gong Z
(2019)
Experimental Investigation of Aerodynamic Hysteresis Using a Five-Degree-of-Freedom Wind-Tunnel Maneuver Rig
in Journal of Aircraft
Gonzalez-Buelga A
(2015)
An electromagnetic vibration absorber with harvesting and tuning capabilities Optimization of an Adaptive Electromagnetic Vibration Absorber capabilities
in Structural Control and Health Monitoring
Gonzalez-Buelga A
(2017)
Assessing the effect of nonlinearities on the performance of a tuned inerter damper Effect of Nonlinearities on a Tuned Inerter Damper Performance
in Structural Control and Health Monitoring
Gonzalez-Buelga A
(2014)
An optimised tuned mass damper/harvester device AN OPTIMISED TUNED MASS DAMPER/HARVESTER DEVICE
in Structural Control and Health Monitoring
Gonzalez-Buelga A
(2015)
An electromagnetic inerter-based vibration suppression device
in Smart Materials and Structures
Gonzalez-Buelga A.
(2014)
Combining vibration control and energy harvesting
in Proceedings of the International Conference on Structural Dynamic , EURODYN
Hill T
(2015)
Interpreting the forced responses of a two-degree-of-freedom nonlinear oscillator using backbone curves
in Journal of Sound and Vibration
Hill T
(2016)
An analytical approach for detecting isolated periodic solution branches in weakly nonlinear structures
in Journal of Sound and Vibration
Hill T
(2016)
Fast Bayesian identification of a class of elastic weakly nonlinear systems using backbone curves
in Journal of Sound and Vibration
Hill T
(2016)
The influence of phase-locking on internal resonance from a nonlinear normal mode perspective
in Journal of Sound and Vibration
Hill TL
(2017)
Identifying the significance of nonlinear normal modes.
in Proceedings. Mathematical, physical, and engineering sciences
Hill TL
(2015)
Out-of-unison resonance in weakly nonlinear coupled oscillators.
in Proceedings. Mathematical, physical, and engineering sciences
Howcroft C
(2015)
Shimmy of an Aircraft Main Landing Gear With Geometric Coupling and Mechanical Freeplay
in Journal of Computational and Nonlinear Dynamics
Howcroft C
(2019)
Efficient aeroelastic beam modelling and the selection of a structural shape basis
in International Journal of Non-Linear Mechanics
Howcroft C
(2018)
On the geometrically exact low-order modelling of a flexible beam: formulation and numerical tests.
in Proceedings. Mathematical, physical, and engineering sciences
J.M Londono
(2014)
Vibration testing of large scale nonlinear structures
in ISMA2014
Kewley S
(2016)
Investigation into the Interaction of Nose Landing Gear and Fuselage Dynamics
in Journal of Aircraft
Knowles JA
(2014)
A bifurcation study to guide the design of a landing gear with a combined uplock/downlock mechanism.
in Proceedings. Mathematical, physical, and engineering sciences
Lazar I
(2016)
Vibration suppression of cables using tuned inerter dampers
in Engineering Structures
Lazar I
(2013)
Using an inerter-based device for structural vibration suppression
in Earthquake Engineering & Structural Dynamics
Li Y
(2019)
Identification of beneficial mass-included inerter-based vibration suppression configurations
in Journal of the Franklin Institute
Li Y
(2017)
Optimal Inerter-Based Shock-Strut Configurations for Landing-Gear Touchdown Performance
in Journal of Aircraft
Li Y
(2017)
Using continuation analysis to identify shimmy-suppression devices for an aircraft main landing gear
in Journal of Sound and Vibration
Li Y
(2017)
Inerter-Based Configurations for Main-Landing-Gear Shimmy Suppression
in Journal of Aircraft
Li Y
(2016)
Optimisation of shimmy suppression device in an aircraft main landing gear
in Journal of Physics: Conference Series
Li Y
(2019)
Optimal fluid passageway design methodology for hydraulic engine mounts considering both low and high frequency performances
in Journal of Vibration and Control
Liu X
(2015)
$$N-1$$ N - 1 modal interactions of a three-degree-of-freedom system with cubic elastic nonlinearities
in Nonlinear Dynamics
Liu X
(2016)
Nonlinear Dynamics, Volume 1
Londoño J
(2017)
Identification of systems containing nonlinear stiffnesses using backbone curves
in Mechanical Systems and Signal Processing
Londoño J
(2015)
Identification of backbone curves of nonlinear systems from resonance decay responses
in Journal of Sound and Vibration
| Description | We have developed a method of understanding the dynamics of vibrating structures that behave in complex ways due to stiffness nonlinearities. Currently this is at the stage where, for conceptually simple structures, we can experimentally identify key parameters which can be used to inform a model of the structure. This has to date been validated based on a simulation case study. |
| Exploitation Route | The findings have been extensively reported in journal papers and keynote talks. The have also been presented to industrial collaborators. |
| Sectors | Aerospace, Defence and Marine |
| Description | Currently the findings have been reported via papers and key note talks and are being used to develop a technique for analysing the nonlinear dynamics of structures by projecting the nonlinear behaviour into the linear modal coordinates. |
| First Year Of Impact | 2016 |
| Sector | Aerospace, Defence and Marine |
| Title | Application of control-based continuation to a nonlinear structure with harmonically coupled modes |
| Description | Experimental data associated with publication in Mechanical Systems and Signal Processing |
| Type Of Material | Database/Collection of data |
| Year Produced | 2018 |
| Provided To Others? | Yes |
| Title | Black Si paper |
| Description | Paper on diamond coated black Si electrodes. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2016 |
| Provided To Others? | Yes |
| Title | Dynamic Design Tools |
| Description | EPSRC Fellowship EP/K005375/1 - Simon Neild. (project renamed from epsrc_fellowship) |
| Type Of Material | Database/Collection of data |
| Year Produced | 2016 |
| Provided To Others? | Yes |
| Title | Dynamic Design Tools 2 |
| Description | EPSRC Fellowship EP/K005375/1 - Simon Neild. (project renamed from epsrc_fellowship) |
| Type Of Material | Database/Collection of data |
| Year Produced | 2016 |
| Provided To Others? | Yes |
| Title | indentifying significance of nnms |
| Description | Dataset for: "Identifying the significance of nonlinear normal modes". Authors: TL Hill, A Cammarano, SA Neild and DAW Barton. Journal: Proceedings of the Royal Society A. EPSRC Fellowship EP/K005375/1 - Simon Neild. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2017 |
| Provided To Others? | Yes |
| Title | substructurability |
| Description | work under EPSRC Fellowship EP/K005375/1 - Simon Neild. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2016 |
| Provided To Others? | Yes |
| Description | Inaugural Lecture (public lecture) |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | Yes |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | over 110 people attended the lecture, which was aimed at an informed but lay audience. Generated discussions with colleagues across the engineering disciplines and with members of the public |
| Year(s) Of Engagement Activity | 2014 |
| URL | http://www.bristol.ac.uk/pace/public-events/inaugural/2014/neild.html |