This article describes the research framework for adaptive structures and the design concept of trans- formable joints. The research of adaptive structures can be splitted into different scales: deformation mechanisms (whole structure), cooperation mechanisms (inter-component) and actuation mechanisms (intra-component). This research will focus on transformable joints, which are based on special mate- rial properties (actuation) to accomplish the change of joint stiffness between locked and released states (transformation). Thereby, the control of DOF can be achieved, in order to finally realise the whole structure’s form change (deformation). Alternatively under shock loads, the joints release and the structure occur certain deformation to dissipate energy and adjust to external loads. Afterwards, the structure recovers its original shape and removes residual strain through special/smart materials. Then the released joints relock again. By comparison of natural role models and adaptive structures, there are many similarities between them that we can learn from nature. In future research, e.g. adap- tive stiffness, the experimental tests of potential materials and prototypes will be the main research methods. While for adaptive geometry, the knowledge of robotics, especially the part of geometric representations and transformations, will help to express this problem in mathematical way. This part will be mostly in conceptual level, so computer simulation will be used. The final goal of this research is to develop energy dissipation and shape-morphing strategies using transformable joints under vary- ing loads as well as shock impact. These kinds of joints can not only be applied to tessellated shell structures, but also introduced to active facade systems.
adaptive geometry, adaptive stiffness, control of DOF, deformation, energy dissipation, flexible components, stiff components, transformable joints.
 Miura, K. & Furuya, H., Adaptive structure concept for future space applications. AIAA American Institute of Aeronautics and Astronautics Journal, 26(8), pp. 995–1002, 1988. http://dx.doi.org/10.2514/3.10002
 Sobek, W. & Teuffel, P., Adaptive systems in architecture and structural engineering. SPIE’s 8th Annual International Symposium on Smart Structures and Materials, pp. 36–45, 2001.
 Vincent, J.F., Bogatyreva, O.A., Bogatyrev, N.R., Bowyer, A. & Pahl, A.K., Biomimet- ics: its practice and theory. Journal of the Royal Society Interface, 3(9), pp. 471–482, 2006. http://dx.doi.org/10.1098/rsif.2006.0127
 Magna, R., Gabler, M., Reichert, S., Schwinn, T., Waimer, F., Menges, A. & Knippers, J., From nature to fabrication: biomimetic design principles for the production of com- plex spatial structures. International Journal of Space Structures, 28(1), pp. 27–40, 2013. http://dx.doi.org/10.1260/0266-35220.127.116.11
 Wiedemann, M. & Sinapius, M. (eds), Nano-micro-macro (Chapter 2). In Adaptive, Tolerant and Efficient Composite Structures, Springer Science+Business Media: New York, pp. 17–27, 2012.
 Knippers, J. & Speck, T., Design and construction principles in nature and architecture. Bioinspiration & Biomimetics, 7(1), pp. 15–25, 2012. http://dx.doi.org/10.1088/1748-3182/7/1/015002
 Multifunctional simulation of complex biological and biomimetic designs and materi- als; Germany IMFW/Universität Stuttgart, Biological Design and Integrative Structures, Krebs, A & Buck, G. available at http://www.trr141.de/index.php/research-areas-2/b03/
 Lienhard, J. & Knippers, J., Considerations on the scaling of bending-active structures. International Journal of Space Structures, 28(3), pp. 137–148, 2013.
 Adaptive structure. (n.d.) McGraw-Hill Dictionary of Scientific & Technical Terms, 6E. available at http://encyclopedia2.thefreedictionary.com/adaptive+structure
 Habraken A.P.H.W., Sleddens W. & Teuffel P.M., Adaptable lightweight structures to minimize material use. Proceeding of the 6th International Conference on Textile Com- posites and Inflatable Structures, Structures Membranes 2013, eds K.-U. Bletzinger, B. Kröplin & E. Oñate.- S.l: Technische Universiteit Eindhoven, pp. 1–12, 2013.
 Gaudenzi, P., Introduction to smart structures (Chapter 1). Smart Structures: Physical Behaviour, Mathematical Modelling and Applications, John Wiley & Sons: New York, pp. 1–34, 2009.
 Lelieveld, C.M.J.L., Smart Materials for the Realization of an Adaptive Building Component, Delft University of Technology: Delft, 2013.
 Speck, T., Knippers, J. & Speck, O., Self-X materials and structures in nature and technology: bio-inspiration as a driving force for technical innovation. Architectural Design, 85(5), pp. 34–39, 2015. http://dx.doi.org/10.1002/ad.1951
 Schleicher, S., Lienhard, J., Poppinga, S., Speck, T. & Knippers, J., A methodology for transferring principles of plant movements to elastic systems in architecture. Computer- Aided Design, 60, pp. 105–117, 2015. http://dx.doi.org/10.1016/j.cad.2014.01.005
 Lienhard, J., Schleicher, S., Poppinga, S., Masselter, T., Milwich, M., Speck, T. & Knippers, J., Flectofin: a hingeless flapping mechanism inspired by nature. Bioinspira- tion & Biomimetics, 6(4), pp. 45–52, 2011. http://dx.doi.org/10.1088/1748-3182/6/4/045001
 Burgert, I. & Fratzl, P., Actuation systems in plants as prototypes for bioinspired devices. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 367(1893), pp. 1541–1557, 2009.
 Liu, Y., Du, H., Liu, L. & Leng, J., Shape memory polymers and their composites in aerospace applications: a review. Smart Materials and Structures, 23(2), pp. 1–23, 2014. http://dx.doi.org/10.1088/0964-1726/23/2/023001
 Lelieveld, C., Jansen, K. & Teuffel, P., Mechanical characterization of a shape morph- ing smart composite with embedded shape memory alloys in a shape memory polymer matrix. Journal of Intelligent Material Systems and Structures, 1045389X15620035, 2015.
 Pickering, K., (eds), Matrices for natural-fibre reinforced composites (Chapter 2). In Properties and Performance of Natural-Fibre Composites, Elsevier: Amsterdam, pp. 67–126, 2008.
 Deshmukh, S.S. & McKinley, G.H., Adaptive energy-absorbing materials using field- responsive fluid-impregnated cellular solids. Smart Materials and Structures, 16(1), pp. 106–113, 2006. http://dx.doi.org/10.1088/0964-1726/16/1/013
 Zhang, X.Z., Li, W.H. & Gong, X.L., The rheology of shear thickening fluid (STF) and the dynamic performance of an STF-filled damper. Smart Materials and Structures, 17(3), pp. 27–35, 2008. http://dx.doi.org/10.1088/0964-1726/17/3/035027
 Woerner, M., Weickgenannt, M., Neuhaeuser, S., Goehrle, C., Sobek, W. & Sawodny, O., Kinematic modeling of a hydraulically actuated 3-SPR-parallel manipulator for an adaptive shell structure. In Advanced Intelligent Mechatronics (AIM), 2013 IEEE/ ASME International Conference, IEEE, pp. 1330–1336, 2013.
 Ledezma-Ramirez, D., Ferguson, N. & Brennan, M., Energy Dissipation using Variable Stiffness in a Single-Degree-of-Freedom Model, Eurodyn: Southampton, 2008. http://dx.doi.org/10.1016/j.jsv.2012.06.010
 Ledezma-Ramirez, D.F., Ferguson, N.S. & Brennan, M.J., An experimental switch- able stiffness device for shock isolation. Journal of Sound and Vibration, 331(23), pp. 4987–5001, 2012.
 Wagg, D., Bond, I., Weaver, P. & Friswell, M. (eds), Adaptive structures –some biologi- cal paradigms (Chapter 10). In Adaptive Structures: Engineering Applications, John Wiley & Sons: New York, pp. 261–283, 2008.
 Dye, S.F., The knee as a biologic transmission with an envelope of function: a theory. Clinical Orthopaedics and Related Research, 325, pp. 10–18, 1996. http://dx.doi.org/10.1097/00003086-199604000-00003