Metamorphosing, or "morphing", structures undergo radical and elastic changes in shape without compromising material limitations. We obtain solutions by favourably combining the effects of non-linear large deformation, pre-stress, and material constitutive behaviour. Their shape-changing purpose imparts extra functionality to the original structure without affecting its integrity. Applications range from extra-compact, unfurling portable electronic devices to shape-changing vehicles that tailor their own aerodynamical properties.

1. A D Norman, K A Seffen & S D Guest, "Morphing of Curved Corrugated Shells", (2009) International Journal of Solids and Structures, 46, pp.1624-1633
2. K A Seffen, "Multistable Anisotropic Shells: Governing Equations of Deformation", (2008) Technical Report, CUED/D-STRUCT/TR 225
3. C Gentilini, K A Seffen, S D Guest & L Nobile, "On the Behaviour of Corrugated Plates in Bending", (2008) Proceedings of AES-ATEMA 2008, Second International Conference, Cesena, Italy, pp.117-120
4. C Gentilini, K A Seffen, S D Guest & L Nobile, "On the Effect of Pre-stress on the Bistable Behaviour of Tape-springs", (2008) Proceedings of AES-ATEMA 2008, Second International Conference, Cesena, Italy, pp.181-185
5. A D Norman, M R Golabchi, K A Seffen & S D Guest, "Multistable Textured Shell Structures", (2008) Advances in Science and Technology, 54, pp.168-173, presented first at the Third International Conference on Smart Materials, Structures, Systems (CIMTEC 2008), Sicily 2008
6. A D Norman, K A Seffen & S D Guest, "Multistable Corrugated Shells", (2008) Proceedings of the Royal Society of London, A, 464(2095) pp.1653-1672
7. A D Norman, S D Guest & K A Seffen, "Novel Multistable Corrugated Structures", (2007) 48th AIAA/ASME/ASCE/AHS/ ASC Structures, Structural Dynamics and Materials Conference, 23-26 April, Hawaii
8. K A Seffen, "Hierarchical Multi-stable Shapes in Mechanical Memory Metal", (2007) Scripta Materilia, 56(5), pp.417-420
9. K A Seffen, "Morphing Bi-stable Orthotropic Elliptical Shallow Shells", (2007) Proceedings of the Royal Society of London, A, 463(2077), pp.67-84
10. K A Seffen, "Mechanical Memory Metal: a Novel Material for Developing Morphing Engineering Structures", (2006) Scripta Materialia, 55(4), pp.411-414
11. K A Seffen, SD Guest & AD Norman, "Multistable Structural Member and Method for Forming a Multistable Structural Member", (2006) UK Patent Application 0612558.7
12. K A Seffen, "Bi-stable Concepts for Reconfigurable Structures", (2004) Structures TC Special Session on Concepts for Morphing and Reconfigurable Structures, 45th Structures and Structural Dynamics, and Materials Conference, 19-22 April 2004, Palm Springs, California, Paper 2004-1526
13. K A Seffen, "A Novel Bi-stable Modular Structure", (2003) Technical report, CUED/D-STRUCT/TR 208

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Wrinkling of thin membranes are an aspect of everyday life; from the way in which fabric drapes over supporting structures to the formation of facial laugh lines and bodily creases in human skin. This project is concerned with producing highly accurate, pre-tensioned surfaces that act as reflectors but where wrinkles will inevitably form at support points, thereby disrupting the surface integrity; we are therefore aiming to devise a scheme for predicting and mitigating wrinkles in such membranes.

1. M J Santer & K A Seffen, "Optical Space Telescopes Structures: The State of the Art and Future Directions", (2009) Aeronautical Journal, 113(1148), paper 3348
2. A Bonin, K A Seffen & M J Santer, "Small-Diameter Membrane Reflector Wrinkling", (2009) 50th AIAA/ASME/ASCE/AHS/ ASC Structures, Structural Dynamics and Materials Conference, 4-7 May, Palm Springs, California, paper 2164
3. M J Santer, A Bonin & K A Seffen, "Small-Diameter Membrane Reflector Structures", (2009) 50th AIAA/ASME/ASCE/AHS/ ASC Structures, Structural Dynamics and Materials Conference, 4-7 May, Palm Springs, California, paper 2150
4. A Bonin, "Shape Control of Wrinkled Membranes", (2008), First Year PhD Report, University of Cambridge

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Our work is concerned with exploiting material activation and novel geometrical concepts, for creating structural actuators with no moving parts, capable of delivering relatively large displacements. Such purpose permits devices of mechanical simplicity for use in novel applications where there is demand for control of large changes in shape, e.g. as in digital loudspeaker technology. Thematically, the work complements problems involving thermal buckling, where one aim is to limit displacements, to improve processing quality, as in the production of semiconductor wafers by a rapid irradiation method.

1. K A Seffen & R A McMahon, "Thermal Buckling of a Uniform Disk", (2007) International Journal of Mechanical Sciences, 49(2), pp.230-238
2. K A Seffen, "Theoretical Performance of a Coiled Coil Piezoelectric Bimorph", (2007) Sensors and Actuators A: Physical, 133(2), pp.486-492
3. K A Seffen, "Thermal Buckling of a Thin, Uniform Circular Disk: a Comparison of Predictions", (2006) Aeronautical Journal, 110(1112), pp.691-693
4. M P Smith, K A Seffen, R A McMahon & W Skorupa, "Analysis of Wafer Stresses During Millisecond Thermal Processing", (2006) Journal of Applied Physics, 100(6), article no. 63515
5. M P Smith, K A Seffen, R A McMahon, W Anwand & W Skorupa, "Thermally Induced Deformation and Stresses During Millisecond Flash Lamp Annealing", (2006) Materials Research Society (MRS) Spring Meeting 2, Symposium C, 17-21 April, San Francisco, California, Paper 0912-C04-08
6. M P Smith, R A McMahon, K A Seffen, D Panknin, M Voelskow & W Skorupa, "Thermal and Stress Modelling for the Flash Lamp Crystallisation of Amorphous Silicon Films", (2006) Materials Research Society (MRS) Spring Meeting 2, Symposium A, 17-21 April, San Francisco, California, Paper 0910-A21-15
7. K A Seffen, "Heating of a Uniform Thin Disk by Finite Elements", (2005) Technical Report, CUED/D-STRUC/TR 217
8. K A Seffen & E Toews, "Hyperhelical Actuators: Coils and Coiled Coils", (2004) 12th AIAA/ASME/AHS Adaptive Structures Conference, 19-22 April 2004, Palm Springs, California, Paper 2004-1814
9. K A Seffen, "Actuation of Large Displacements by Smart Hyperhelices", (2003) Technical report, CUED/D-STRUCT/TR 206
10. K A Seffen, "Analysis of Transducers for Digital Loudspeakers and Phased Array Antennae", (2003) Classified final technical report for the European Commission under Framework V, contract no. GR1D-CRT99-0121, CUED/D-STRUCT/TR 205
11. K A Seffen, "Analysis of Coiled Piezoelectric Structures", (2002) Proceedings of New Approaches to Structural Mechanics, Shell and Biological Structures, Cambridge, September 2002, Eds S Pellegrino & H R Drew, Kluwer, pp.215-227
12. D H Pearce, K A Seffen & T W Button, "Net Shape Formed Spiral and Helical Piezoelectric Actuators", (2002) Journal of Materials Science, 37, pp.3117-3122
13. K A Seffen & M Aleyaasin, "Analysis of Transducers for Digital Loudspeakers and Phased Array Antennae", (2002) Classified two-yearly technical report for the European Commission under Framework V, contract no. GR1D-CRT99-0121, CUED/D-STRUCT/TR 200
14. K A Seffen & D J Butler, "An Exercise in Elementary Smart Structures", (2002) International Journal of Mechanical Engineering Education, 30(1), pp.59-72
15. K A Seffen, "Through-Thickness Effects in Curved Piezoelectric Beams", (2001) Technical report, UMIST/ME/AM/14.05.01/CURV1
16. K A Seffen, "Analysis of Transducers for Digital Loudspeakers and Phased Array Antennae", (2001) Classified 12-monthly technical report for the European Commission under Framework V, contract no. GR1D-CRT99-0121, UMIST/ME/AM/09.05.01/PADS2
17. K A Seffen, "Analysis of a Smart, Linear, Piezoelectric Transducer", (2000) Proceedings of the Society of Photo-Optical and Instrumentation Engineers (SPIE) 7th Annual International Symposium on Smart Structures and Materials, Newport Beach, Calif., March 2000, Ed. N. Wereley, 3985, pp.660-671
18. K A Seffen, "Analysis of Transducers for Digital Loudspeakers and Phased Array Antennae", (2000) Classified six-monthly technical report for the European Commission under Framework V, contract no. GR1D-CRT99-0121, UMIST/ME/AM/16.11.00/PADS1

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We are not concerned with biomimetics, rather, with understanding particular biological processes from the engineering perspective, by treating the biological tissue as an engineering material. Our work has largely focussed on the response of skin tissue to thermal activation, in order to gauge pain levels for efficacious heat treatments. Other recent work includes the quantification of the mechanical properties of genetically engineered plants for use in bio-fuels (see the University's bioenergy initiative).

1. F Goubet, C J Barton, J C Mortimer, X Xu, Z Zhang, G P Miles, J Richens, A Liepmann, K A Seffen & P Dupree, "Cell Wall Glucomannan in Arabidopsis is Synthesised by CSLA Glycosyltransfereases, and Influences the Speed of Embryogenesis", (2009), the Plant Journal, to appear
2. F Xu, T J Lu, K A Seffen & E Y K Ng, "Mathematical Modeling of Skin Bioheat Transfer", (2009) Applied Mechanics Reviews, ASME, to appear
3. F Xu, T J Lu & K A Seffen, "Effect of Thermal Damage on the Compressive Behaviour of Skin Tissue", (2009) Journal of Mechanics in Medicine and Biology, 9(1), pp.81-104
4. F Xu, T J Lu & K A Seffen, "Dual-Phase-Lag Heat Model of Skin Heat transfer", (2008) International Conference on Biomedical Engineering and Informatics, 28-30 May 2008, Sanya, China
5. F Xu, T Wen, T J Lu & K A Seffen, "Modelling of Nociceptor Transduction in Skin Thermal Pain Sensation", (2008) ASME Journal of Biomechanical Engineering, 130(4), 041013, pp.1-13
6. F Xu, T Wen, K A Seffen & T J Lu, "Modelling of Skin Thermal Pain - a Preliminary Study", (2008) Applied Mathematics and Computation, doi:10.1016/j.amc.2008.05.045, presented first at the International Conference on Life System Modelling and Simulation (LSMS'2007), Shanghai, China 2007
7. F Xu, T Wen, T J Lu & K A Seffen, "Quantification of Thermal Damage in Skin Tissue", (2008) Academic Journal of Xian Jiaotong University, 20(1), pp.1-8
8. F Xu, T J Lu & K A Seffen, "Skin Thermal Pain Modelling. A Holistic Method", (2008), Journal of Thermal Biology, 33(4), pp.223-237
9. F Xu, T Wen, T J Lu & K A Seffen, "Biothermomechanics of Skin Tissue", (2008) Journal of the Mechanics and Physics of Solids, 56(5), pp.1852-1884
10. F Xu, T J Lu & K A Seffen, "Biothermomechanical Behaviour of Skin Tissue", (2008) Acta Mechanica Sinica, 24(1), pp.1-23
11. F Xu, T Wen, T J Lu & K A Seffen, "Non-Fourier Analysis of Skin Biothermomechanics", (2008) International Journal of Heat and Mass Transfer, 51(9,10), pp.2237-2259
12. F Xu, T Wen, T J Lu & K A Seffen, "Skin Biothermomechanics for Medical Treatments", (2008) Journal of the Mechanical Behaviour of Biomedical Materials, 1(2), pp.172-187
13. F Xu, K A Seffen & T J Lu, "Temperature-Dependent Mechanical Behaviors of Skin Tissue", (2008) IAENG International Journal of Computer Science, 35(1), pp.92-101
14. F Xu, T Wen, K A Seffen & T J Lu, "Modelling of Skin Thermal Pain - a Preliminary Study", (2007) International Conference on Life System Modelling and Simulation (LSMS'2007), Shanghai, China 2007
15. F Xu, T Wen, K A Seffen & T J Lu, "Characterization of Thermomechanical Behaviour of Skin Tissue II. Viscoelastic Behaviour", (2007) IAENG (WCE) International Conference of Systems Biology and Bioengineering (ICSBB'07), 2-4 July 2007, London , UK
16. F Xu, T Wen, K A Seffen & T J Lu, "Characterization of Thermomechanical Behaviour of Skin Tissue I. Tensile and Compressive Behaviours", (2007) IAENG (WCE) International Conference of Systems Biology and Bioengineering (ICSBB'07), 2-4 July 2007, London , UK
17. F Xu, T Wen, K A Seffen & T J Lu, "Mathematical Modelling on Nociception of Skin Thermal Pain", poster & abstract, 19th Annual Cambridge Neuroscience Seminar (NS 2007), 20 April 2007, Cambridge, UK

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This research follows on from the PhD work of KAS, where he considered the deployment of foldable elastic structures for use on spacecraft. In this earlier work, the principle novelty was in modelling the natural deployment dynamics in terms of variable mass systems. This work has been recently re-activated in view of work on the collapse of tall buildings, specifically, with regard to the collapse of the WTC Towers on 9/11.

1. K A Seffen,"Progressive Collapse of the World Trade Centre: Simple Analysis", (2008) ASCE Journal of Engineering Mechanics, 134(2), pp.125-132
2. K A Seffen, "On the Behaviour of Folded Tape-Springs", (2001) Journal of Applied Mechanics, Trans. ASME, 68, pp.369-375
3. K A Seffen, Z You & S Pellegrino, "Folding and Deployment of Curved Springs", (2000) International Journal of Mechanical Sciences, 42, pp.2055-2073
4. K A Seffen, S Pellegrino & G T Parks, "Deployment of a Panel by Tape-Spring Hinges", (2000) Proceedings of IUTAM-IASS Symposium on Deployable Structures: Theory and Applications, Cambridge, September 1998, Eds S Pellegrino and S D Guest, Kluwer, pp.355-364
5. K A Seffen & S Pellegrino, "Deployment Dynamics of Tape-Springs", (1999) Proceedings of the Royal Society of London, A, 455(1983), pp.1003-1048
6. K A Seffen, Z You & S Pellegrino, "Folding and Deployment of Curved Tape-Springs", (1997) Technical report, CUED/D-STRUCT/TR 171
7. K A Seffen & S Pellegrino, "Deployment of a Rigid Panel by Tape-Springs", (1997) Technical report, CUED/D-STRUCT/TR 168
8. K A Seffen, "Analysis of Structures Deployed by Tape-Springs", (1997) Ph.D. Thesis, University of Cambridge
9. K A Seffen & S Pellegrino, "Deployment Dynamics of Strip Springs", (1996) Proceedings of 19th International Congress of Theoretical and Applied Mechanics, Kyoto, August 1996 (abstract)
10. K A Seffen & S Pellegrino, "Deployment Dynamics of Elastic Folds in Transversely Curved Thin Strips", (1995) Proceedings of Symposium on Instabilities in Solids and Structures, UCLA, June 1995 (abstract)
11. K A Seffen, "Unconstrained Deployment of a Collapsible Membrane Reflector", (1994) First Year PhD Report, University of Cambridge

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This bulk of projects below were carried out by KAS as a postdoctoral researcher and thus, are now completed. The general theme centered on the quantification of design, in pursuit of optimal configurations of device. For example, strict concepts in control theory were brought to bear on the solution of bicycle-rider interaction, in order to enable the prediction of the controllability and hence, safety of new, alternative bicycle layouts.A new topic is in the optimal design of radically efficient aircraft.

1. T I Saeed, W R Graham, H Babinsky, J P Eastwood, C A Hall, J P Jarrett, M M Lone & K A Seffen, "Conceptual Design for a Laminar Flying Wing Aircraft", (2009), 27th AIAA Applied Aerodynamics Conference, 22-25 June, San Antonio, Texas, paper 3616-615
2. S D Waller & K A Seffen, "Shape Optimisation of Cantilevers", (2005) Technical Report, CUED/D-STRUCT/TR 216
3. S D Waller & K A Seffen, "Compression Modelling of Pin-Jointed Trusses", (2005) OPTI2005, 9th International Conference on Computer Aided Optimum Design in Engineering IX, 23-25 May 2005, Skiathos, Greece, pp.165-173
4. K A Seffen, G T Parks & P J Clarkson, "Observations on the Controllability of Motion of Two-Wheelers", (2001) Proceedings of the Institute of Mechanical Engineers, Part I: Systems and Control Engineering, 215, pp.143-156
5. A Suppapitnarm, K A Seffen, G T Parks & P J Clarkson, "A Simulated Annealing Algorithm for Multiobjective Optimisation", (2000) Engineering Optimisation, 33(1), pp.59-85
6. A Suppapitnarm, K A Seffen, G T Parks & P J Clarkson, "Design by Multiobjective Optimisation Using Simulated Annealing", (1999) International Conference on Engineering Design (ICED'99), Munich, August 1999, Ed. V. Lindemann, H. Birkhofer, H. Meerkamm, S. Vanja, pp.1395-1400, Publ. Technische Universitat Munchen
7. P J Clarkson, K A Seffen, G T Parks, A Hooley & W S Bainbridge, "Observations on Virtual Collaborative Design", (1999) International Conference on Engineering Design (ICED'99), Munich, August 1999, Ed. V. Lindemann, H. Birkhofer, H. Meerkamm, S. Vanja, pp.1837-1840
8. A Suppapitnarm, K A Seffen, G T Parks, A M Connor & P J Clarkson, "Multobjective Optimisation of Bicycle Frames Using Simulated Annealing", (1999) Proceedings of 1st ASMO/ISSMO Conference on Engineering Design Optimization, Ilkley, July 1999, Ed. V.V. Toporov, pp.357-364
9. A M Connor, K A Seffen, G T Parks & P J Clarkson, "Efficient Optimisation of Structures Using Tabu Search", (1999) Proceedings of 1st ASMO/ISSMO Conference on Engineering Design Optimization, Ilkley, July 1999, Ed. V.V. Toporov, pp.127-134
10. K A Seffen, "Bicycle-Rider Dynamics; Equations of Motion and Controllability", (1999) Joint technical report: UMIST/ME/AM/15.07.99/CUED; Cambridge University Engineering Department CUED/C-EDC/TR 79

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