Investigation of highly flexible, deployable structures: review, identification, control, application by Noémi Friedman Summary of the thesis to be presented to ENS de Cachan (France) and BME (Hungary) in fulfillment of the thesis requirement for the degree of Doctor of Philosophy in Civil Engineering Responsible: Prof. György Farkas, Prof. Adnan Ibrahgimbegovic Budapest, 2011 ©Noémi Friedman 2011 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman INDEX 1. Introduction, aim of scope ......................................... 3 3. Architectural background ........................................... 5 4. Analysis of a simplified planar model ......................... 7 5. Analysis of packing antiprismatic deployable lattice structures ..................................................................... 10 5HDOL]DWLRQȸH[SHULPHQWVE\SK\VLFDOPRGHOVLGHDVIRU control and applications ............................................... 15 6. Further research perspectives .................................. 16 Acknowledgement ........................................................ 16 References .................................................................... 17 List of publications ....................................................... 18 2 Investigation of highly flexible, deployable structures: review, identification, control, application 1. PhD thesis Noemi Friedman INTRODUCTION, AIM OF SCOPE Observing nature, several transformable structures can be found, like the extensible worm, deployable leaves and wing of insects (Vincent, 2001), expanding virus capsid (Kovács et al., 2004), not to mention the movable structure of our own, human body. For centuries several small scale man-constructed deployable structures have been constructed too, such as umbrellas, chairs, fans etc. For the last four-five decades advanced man-made structures have appeared mainly for spatial engineering applications (booms, solar arrays, antennas, reflectors , ex. (Gantes, 2001; Pellegrino, 2001; Wada et al, 1988)), as the volume and the weight of a structure to be transported to space is crucial. On earth, for architecture it had been mainly used until nowadays for only very small scale tents, yurts and shelters. Confirming to the novel conceptions of the 21th century and due to available numerical and robotics technologies advanced transformable structures are already applied in civil engineering and architecture too. Structures used for off-shore industry and light deployable structures used for modern architecture can be mentioned among these. These structures are designed to undergo very large displacements and remain fully operational (Ibrahimbegovic, 2003). Often the structures of that kind can integrate a multibody system (e.g. Ibrahimbegovic and Taylor, 2003 or Ibrahimbegovic and Schiehlen, 2001) which facilitates a construction phase before being integrated in a structural assembly (e.g. Gant, 1996). Modeling of the component of 3D frame-type flexible structures of this kind is nowadays under control thanks to the geometrically exact beam model (Ibrahimbegovic and Taylor, 2002; Ibrahimbegovic and Mamouri, 2000) capable of representing large displacement and rotations, and solving the pertinent instability problems (Ibrahimbegovic and Al Mikdad, 2000). :LWKWKHKHOSRIWKHVHWRROVWKHGHSOR\DEOHDQWLSULVPDWLFVWUXFWXUHSURSRVHGE\+HJHGĦV (+HJHGĦV ) will be analyzed, which was chosen because of the lack of profound knowledge about its mechanical behavior and the absence from transformable system practice. Concerning mechanical behavior of space truss systems generated from the edges of a regular antiprism the results are rather fascinating. Tarnai had shown that a space truss generated from even sided regular antiprism is a finite mechanism while the ones from odd sided antiprisms are stable forms (Tarnai, 2001). Nevertheless by building stable truss units (formed from odd sided antiprisms) on top of each other, forming a cylindrical truss, small displacements of boundary joints at the bottom grow exponentially along the height +HJHGĦV 1986). Consequently it is rather to be avoided to apply such regular antiprismatic trusses for conventional engineering applications without any additional stiffening. Nonetheless this geometry can serve for the construction of a very interesting pop-up mast. The first challenge already is to fully master the construction phases of a flexible, deployable structure which takes any structure component from initial unstressed state to a `deformed` yet equilibrated state. Naturally the popping up of the structure necessitates a thorough dynamical analysis and vibration control. However the packing of the structure even by smoothly controlling boundary displacements may also cause inertial effects that cannot be ignored due to intermediate snapping of the structure. However within the refines of the thesis the scope was only to investigate the packing behavior of the structure without taking into account these inertial effects in the simulations. 3 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman The thesis was organized in four larger blocks. In the first block an extensive but not exhaustive review on different transformable V\VWHPVʊUHWUDFWDEOHURRIVGHSloyable and retractable pantographic lattice systems, tensegrity VWUXFWXUHV VRIW PHPEUDQHVWUXFWXUHVDQGSQHXPDWLFV\VWHPVʊXVHG LQDUFKLWHFWXUHDQGFLYLO engineering will be given. Though the main research topic of the authors within the theme of transformable structures is just a small slice, this study was carried out to explore earlier and current researches and technologies to demonstrate the wide range of available systems, their historical background and their potentials in the future. The second block introduces the problem of investigating packing behavior of the antiprismatic deployable structure through a simplified 2D structure possessing similar packing properties. The equilibrium paths of packing and the concerning difficulties (bifurcation of the path, snap-back phenomenon, singular configurations etc) as well as the packing sequences will be revealed through analytical and numerical research. The third block deals with the same problem but already for the targeted 3D problem. The same analysis presented for 2D structures is carried out for two different type of antiprismatic systems. In this chapter approximations for main mechanical characteristics were also provided from the analytical investigation that can serve as a tool for preliminary design and verification of the numerical results. Finally in the fourth block a try is given to provide ideas for application of antiprismatic structures by compounding the ideas and characteristics of the available systems reviewed. The small physical models built for experimenting was also presented in this block. In this chapter different applications and control systems were sketched without aiming to give detailed solutions. 4 Investigation of highly flexible, deployable structures: review, identification, control, application 3. PhD thesis Noemi Friedman ARCHITECTURAL BACKGROUND After shortly summarizing the historical background an overview on transformable structures used in civil engineering and architecture have been presented. The feature of transformability in case of architectural use can arouse from two different motivations. The first motivation is to create a fast and/or safe construction method and in some cases it can be also the need for a quick demounting process and the possibility of reusability. The second motivation is to adapt the structure to external excitations like functionality requirement or weather conditions. A common example is the off-shore industrial installations where transformability is needed coming from functionality requirements. Less familiar structures are the ones where transformability is coming from energy-saving consideration or the aim can also be to ameliorate occupant comfort, raise the attraction of the building. The former motivation resulted in exotic inventions of some pantographic systems, like the collapsible movable theatre of Pinero, the quickly retractable swimming pool cover of Escrig, even the pop-up dome of Zeigler and its further developments. The minimal material use Tensegrity systems also offer the possibility of foldability. Ongoing research works try to find a greater variety of possible architectural applications. Some soft membrane systems like cable-stiffened textile structures and pneumatic structure can be quickly installed too. F. Otto remarkable systematic study on foldable membrane structures with the recent available material and calculation technologies led to a wide variety of architectural membrane designs even used for big span permanent structures. Pneumatic systems can also serve as a supplementary system for the erection of 3D structures making the installation easier, faster and safer. The “pantadome” structural system invented by Momoru Kawaguchi, and some earlier and novel pneumatic formwork methods for constructing monolithic and precasted concrete domes can be mentioned among these systems. Though these structures mentioned above still attract the military and provisory events in first place a trend can be observed to apply them for permanent buildings where translucent or extremely light construction is needed. With membrane structures that can move while in use can be designed too. The goal to design dynamic structures that are able to change morphological/mechanical/physical properties and behavior as a response to external excitations and requirements was first addressed in the 1960s and 1970s. Early transformable designs appeared in first place for housing sport venues. With the currently growing media 5 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman focus on sport events the demand for retractable structures seems to be steadily increasing. Most of these designs use rigidly moving parts to retract the roof structure. In most of the cases the slicing of an ideal structural shape results in gigantic structural height, and mechanical instruments enabling retraction further increase the costs of these structures. With new generation roofs like the retractable pantograph structure of Hoberman and Pellegrino and the application of a retractable skin fixed to the permanent structure can rather count with economical aspects. Several research topics focus on adapting tensegrity and pantographic structures to adaptive architecture. Combining transformable structures with a highly distributed control system which is already available in today’s technology an intelligent responsive architecture is born. This possibility does not only prospect indoor environmental quality enhancement and better occupant comfort but a better use of natural energy resources and thus a rather sustainable design. 6 Investigation of highly flexible, deployable structures: review, identification, control, application 4. PhD thesis Noemi Friedman ANALYSIS OF A SIMPLIFIED PLANAR MODEL To better understand the behavior of snap-through type antiprismatic lattice structures first a simplified 2D model was identified and investigated manifesting similar properties to the targeted 3D structure. The simplified model consists of elastic horizontal bars of initial length lH0=2r0 and rigid bracing bars (shown on the right). The bracing is only connected to the horizontal bars with joints allowing free rotations. The bracings are not connected to each other at their u crossing point hence allowing free sliding on each other. The top horizontal bar and every second horizontal bar are rigid. A vertical packaging can be obtained by stretching the elastic horizontal bars. The structure has non-symmetrical freedom of motions as well which is to be avoided in the case of a simple deployable mast. Furthermore the analysis will be restricted to only symmetrical movements to the vertical symmetry axis of the structure. This is to be mentioned that it is an important and large restriction. It involves the restriction of global buckling of the structure which should be also investigated in the future. First the packing of the basic segment of the mast was analyzed. Through the kinematical, equilibrium and constitutive equations the force-displacement diagram was deduced associated with the function: The initial and the closed configurations both correspond to zero force. While the former being a stable state the latter is an instable one. The given diagram exhibits an instability phenomenon, which occurs at the critical height: After clarifying the mechanical behavior, the packing of the multi-storey masts were analyzed. Two different type of mast were defined. One is called ‘doubly stiffened’ which is constructed by pilling the basic segment on top of each other and the other is called ‘not stiffened’ which is corresponds to the same topology but all the horizontal stiff bars are replaced to elastic ones. It was shown that the behavior of the ‘doubly-stiffened’ mast can be calculated from the behavior of its basic segments. In case of perfectly identical physical and geometrical parameters the mast can be packed with a uniform packing pattern that is the segments can close simultaneously. Nevertheless this hypothesis is not realistic and consequently the typical equilibrium path corresponds to a bifurcated one. A method to construct the typical force-displacement diagram is provided with and without taking the self-weight into account (see figure beneath for the construction of the latter one). 7 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman From the construction method of the force-displacement diagram the critical segment number was deduced: If the number of analyzed segments was more than violent intermediate snapping is sure to take place during deployment if no segment closes simultaneously. The post-packed phenomenon was defined and presented (see next figure) which may withhold the structure from complete packing and consequently it is to be avoided. Packing sequences and equilibrium paths have been presented for both the restricted and the nonrestricted case. The restricted simulation means restraining the model from disengaging from the completely closed configuration during packing that is with restricted simulation the structure is kept from the post-packed phenomenon. Numerical simulations of the basic segment and the two types of multi-storey structures were carried out. Incremental displacement control analysis was used with the software FEAP with non-linear truss elements with logarithmic stretch model. Different control possibilities have been presented for the investigation of packing behavior. 8 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman For ‘doubly stiffened’ masts the uniform and the successive control was offered by guiding the boundary nodes of paired nodes each segment. The typical path can be traced by introducing for physical imperfections and controlling only the displacement of contact the top nodes. In case of the latter restraining the structure from forces ‘post-packed phenomenon’ is necessary. This was simulated with a penalty method by pairing the end nodes of the rigid bars one under the other (figure on the right). The induced contact force is disproportional to the distance in between the paired nodes and keeps the segments from disengaging from the closed configuration. The intensity of the contact force depends on the manually given penalty parameter which should be carefully chosen. If no snap-back phenomenon occurs during packing capturing the restraint is not difficult (force-displacement diagram from the simulation in the beneath figure). However at the snap-back large value of penalty parameter is needed in order to restrain the ‘post-packed phenomenon’ which may turn the tangent stiffness matrix bad conditioned. The basic segment of a ‘not stiffened’ mast is half of the one of the ‘doubly stiffened’ one. For ‘not stiffened’ masts the same type of controls were applied with some deviations. For uniform and successive packing control all the nodes were guided, however it was shown that this procedure is not practical in case of successive control. Instead only the displacement of every second node was controlled which neither proved to be very efficient because of possible ‘post-packed phenomenon’. With the numerical simulations carried out it was found that the ‘non-stiffened’ masts can only be completely packed in case of even number of segments. This hypothesis was confirmed with analytical explanation. 9 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman 5. ANALYSIS OF PACKING ANTIPRISMATIC DEPLOYABLE LATTICE STRUCTURES An antiprism is a polyhedron composed of two parallel, identical polygons connected by triangles. Antiprisms are similar to prisms except the two polygons are twisted relative to each other and thus the lateral faces are not quadrilaterals but triangles (see Figures to the left). A regular antiprism is formed with a 180/n degree of twisting angle between the two n-sided polygons. 7KH GHSOR\DEOH F\OLQGULFDO FROXPQ RIIHUHG E\ +HJHGĦV shown on the right, consists of rigid panels (octagonal panels in the figure) and rigid and elastic bars (drawn with continuous and dashed lines respectively). The mast is packaged with pushing the top polygonal panel in the vertical direction. With a uniform cyclic symmetric folding the elastic bars are stretching out and the parallel polygonal panels are pushed together. The structure cannot be controlled E\ DQ RQO\ D[LDO IRUFH +HJHGĦV nonetheless with a careful symmetry control the structure can be packed to a theoretically planar truss. In this packaged configuration the structure is in equilibrium without any external forces. This state of self-stress is not a stable position, consequently with a small perturbation the structure can snap back to the initial, deployed, strain-free configuration. First analytical investigations were carried out to describe the mechanical behavior of one segment of the pop-up column. The results can serve for better understanding the basic characteristic of such structures, for a tool to check numerical results before analyzing more complex structural solutions and for a method of preliminary design of optional architectural solutions (mast, framework, bridge, etc.). The basic unit can be packaged by pushing down the top facet of the structure until the bottom facet. This can be achieved by extending the middle polygon to the radius (see Figure to the right): that is the polygonal bars have to stretch to times their initial length, where 10 is: Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman This stretching depends only on the initial height/radius ratio and on the number of the vertex of the polygon ( ), but not on the dimension of the structure. The equilibrium path (see figure beneath) was diagrammed in case of cyclic symmetrical folding assuming linear elastic behavior of polygonal bars end rigid bracings. The function of the equilibrium path is: Where ‘n’ is the number of vertex of the polygon. It is presented that equilibrium path manifests an instable phenomenon that results in a snapping of the structure after passing the critical force. This critical force is reached at the height: And at the value: where The intensity of the critical force depends only on the number of vertex of the polygons, on the initial height/radius ratio ( ) and on the axial stiffness of the elastic bars ( ) but not on the dimension of the structure. 11 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman For the summarized results approximations were offered as a tool for a fast control of numerical results and for preliminary design of architectural applications. These equations for estimating the equilibrium path are: where constants a,b,d,e depend only on the number of vertex of the polygons and are given in the thesis dissertation in Table 4.2 and 4.3. The error of each estimation depends on the actual value of and on . The higher the number of vertex is the smaller the error of the approximation gets. The smaller the value is the smaller the error is. The critical segment number defined for planar structures and its approximation was given for antiprismatic structures as well: The force-displacement diagram is highly asymmetrical. The increment of the ratio and the increment of the number of vertex of the polygon leads to a more emphasized asymmetry of the diagram. The more emphasized the asymmetry of the displacement diagram gets the larger the critical segment number is. The force-displacement diagram of the multi-storey structure can be constructed from the one of the basic unit with the methodology described for planar structures. The typical diagram of a pentagonal six-storey mast was constructed (figure beneath). An example of the typical packing sequence is shown in the figure in the bottom of this page. 12 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman To simulate the packing of the multi-storey structures numerical models were built. The simulation was verified by the comparism of the results with the analytical ones. For the constitutive model logarithmic stretch was used. The simulation of the multi-storey structures was carried out with different controls. After giving examples for the uniform (see next Figure) and successive control of the ‘doubly stiffened mast’ it was shown that by controlling only the displacement of the top nodes the problem of ‘post-packed phenomenon’ occurs. Two different motions were identified under this definition. One is of the same kind that was described for planar structures, that is the segment turns to and upside down position when further pushing its top nodes from completely closed configuration (figure to the right). The second phenomenon is the flipping-up of the bracings (see figure beneath) The problem of the phenomenon was resolved by defining contact elements between the rigid polygons similarly to the methodology used for planar models. This was effectuated by additional nodes placed in the center of the rigid polygons that were linked with a master&slave method to the vertex of the associated polygons. This restricted simulation was performed with controlling the order of the segment-closing by perturbing the axial stiffness of the elastic bars. For the packing analysis of ‘not stiffened’ masts only uniform control was analyzed. Through the analysis it was shown that if the antiprismatic spatial structure has even sided segments the packing takes effect in two phases; in the first phase every polygon expands, in the second phase every first polygon compresses and every second polygon expands. The transition state is where the bracings turn to an upright position. For masts consisting of odd number of segments it was shown that contrary to the planar structure complete packing might be possible if specific geometry is defined. The structure is packable in case of geometry defined by: 13 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman This condition can be demonstrated by a mast consisting of three segments. The completely packed position is shown on the figure to the right. The closed configuration of the top and bottom segment is predefined and the structure is only packable if the length of the bracings connecting the top and bottom segments equals: In contrary to the even sided structures the ‘not stiffened’ antiprismatic masts of odd number of segments are packed by only expanding their polygons. 14 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman 5. 5($/,=$7,21ȸ(;3(5,0ENTS BY PHYSICAL MODELS, IDEAS FOR CONTROL AND APPLICATIONS For the verification of the results some physical models were built (figure on the left). Unfortunately the symmetrical control of ’not stiffened’ antiprismatic masts could not be solved by the simple models. Symmetric conditions however could be easier to control if more sophisticated joints could be applied with limited rotations . In accordance with the built physical models it was concluded that at the stage of the research the initial assumptions of restraining the structure from non-symmetrical motions is rather unrealistic. Nonetheless the packing of non-stiffened multi-storey antiprismatic masts are rather fascinating to analyze. Though result of the experiments with ‘not stiffened’ structures resulted negatively, it is to be mentioned that trying to build the ‘not stiffened’ model led to the discovery of a new type of deployable structure (upper structure in the figure to the left). Concluding the experiments ideas for application and control were only investigated for ‘doubly stiffened’ structures. As a possible application a pedestrian pop-out bridge application is proposed (figure to the right). The elastic stretchable bars could be of rubberlike material while the rigid bars of a more general stiff, light-weight material. In the deployed configuration the elastic bars should resist to compression forces too. For that the elastic material could be thread into a tubular stiff bar, which is loose and can move freely along the elastic bars in the packaged configuration. In the deployed configuration the corresponding joints tighten the stiff bar which has to click into its proper place to be integrated into the structure to ensure the necessary rigidity of the opened bridge. The efficiency of the structure can be raised by keeping it pretensioned in the deployed configuration. The self-stress state can be applied by the elastic bars being still stretched in the opened configuration and by additional longitudinal cables that could be of good help also for the packing control. The geometry of the antiprismatic masts is attractive even without making them a popup structure. If for example instead of the elastic bar a cable is led through the polygon’s edges this cable can already effectively stiffen the structure by prestressing it and at the same time it can serve for deploying the mast. This tensile elements could be either separate ones for each polygon or similarly to the deployable mast designed by Pellegrino a single cable could be led through the structure that can control the deployment (Figure 5.7). If the restriction of symmetrical behavior is relieved the interesting asymmetrical structural forms can be used for adaptive architectural designs, for structures that could change morphological properties due to different external excitations. 15 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman 6. FURTHER RESEARCH PERSPECTIVES In level of the mechanical analysis there are still open questions regarding the ‘not stiffened’ antiprismatic masts. For example the packing pattern of multi-storey masts can seem to be absolutely stochastic but regularities regarding the order of segment closing can be observed. There are different controls that have not been tried yet to simulate the packing of these structures. The most important defect of the thesis is the dynamical analysis of the packing (where snap-through effect occur) and of the pop-up behavior as well as the concerning vibration control. This investigation is intended to carry out in the near future. Regarding the application part only sketches were made, and general ideas were targeted but it is worth to explore the possibilities of architectural applications and to better expertise in the possible controlling options, structural details. ACKNOWLEDGEMENT This work is connected to the scientific program of the ‘Development of qualityoriented and harmonized R+D+I strategy and functional model at BME’ project. This project is supported by the New Hungary Development Plan (Project ID: TÁMOP-4.2.1/B-09/1/KMR2010-0002). 16 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman REFERENCES Gant C. (1996): Proceedings `Conceptual Design of Structures`, Stuttgart, pp. 222-229 Gantes C.J. (2001): Deployable Structures: Analysis and Design, WIT Press, Southampton, Boston; +HJHGĦV , Branching of Equilibrium Paths in a Deployable Column, International Journal of Space Structures, Special Issue, vol 8, page 119-125 +HJHGĦV , Analysis of Lattice Single Layer Cylindrical Structures, Space Structures, vol. 2, page 87-91 Ibrahimbegovic A., Taylor R. L. (2003): Nonlinear Dynamics of Flexible Multibody Systems, Computers and Structures, 81, pp. 1113-1132 Ibrahimbegovic, A., Schiehlen W. (2001): Computational Techniques and Applications in Nonlinear Dynamics of Structures and Multibody System, Proceedings EUROMECH-427, Cachan, September 24-27 Ibrahimbegovic A., Taylor R.L. (2002): On the role of frame-invariance of structural mechanics models at finite rotations, Computer Methods in Applied Mechanics and Engineering, 191, pp. 5159-5176; Ibrahimbegovic A., Mamouri S. (2000): On Rigid Components and Joint Constraints in Nonlinear Dynamics of Flexible Multibody Systems Employing 3D Geometricallz Exact Beam Model, Computer Methods in Applied Mechanics and Engineering Ibrahimbegovic A., Al Mikdad (2000): Quadratically Convergent Direct Calculation of Critical Points for 3D Structures Undergoing Finite Rotations, Computer Methods in Applied Mechanics and Engineering Kovács F., Tarnai T., Guest S.D, Fowler P.W., (2004): Double-link expandohedra: a mechanical model for expansion of a virus, Proc. Roy. Soc. A, vol. 460, No 2051, pp. 31913202 Pellegrino S. (2001): Deployable Structures, Springer-Verlag Wien, New York Tarnai T. (2001): Infinitesimal and Finite Mechanisms in S. Pellegrino Deployable Structures, page 13-143, Springer Wien New York Vincent J.F.V.(2001): Deployable structures in nature, S. Pellegrino: Deployable Structures, Springer-Verlag Wien, New York, pp 37-51; Wada B.K., Fanson J.L., Garba J.A., Chen G.S.(1988): Adaptive structures to meet future requirements for large precision structures, Proceeding of the International Conference on Spacecraft Structure and Mechanical Testing, Noordwijk, Netherlands, pp. 121-126; 17 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman LIST OF PUBLICATIONS Book, chapter in book Friedman, N. ʊ .LVV 5 0 ʊ 9|OJ\L , ʊ .OLQND . Vasbetonszkerkezetek Méretezése az Eurocode 2 Alapján: Gyakorlati Útmutató, ed.LVV50ʊ )ULHGPDQ1$0DJ\DU0pUQ|NL Kamara gondozásában, PI Innovációs Kft., Budapest, Hungary, 2010., 289 p. ISBN: 978 963 88427 49 ,EUDKLPEHJRYLF $ ʊ .XFHURYD $ ʊ %UDQFKHULH ' ʊ +DXWHIHXLOOH 0 ʊ &ROOLDW - % ʊ )ULHGPDQ 1 ʊ =ODWDU 0 Civil Engineering Structures: Multiscale Damage Representation, Identification, Controlled Destruction and Quick Reconstruction, ed. ,EUDKLPEHJRYLF $ ʊ Zlatar, M., Damage Assessment and Reconstruction after War or Natural Disaster, NATO Science for Peace and Security Series, Springer, Dordrecht, Hollandia, 2009. pp. 3-28., ISBN:978-90-4812384-1 )ULHGPDQ1ʊ)DUNDV*\Összecsukható-kinyitható rúdszerkezetek mérnöki alkalmazása, A %XGDSHVWL 0ĦV]DNL pV *D]GDViJWXGRPiQ\L (J\HWHP eStWĘPpUQ|NL .DU +LGDN pV 6]HUNH]HWHN Tanszéke Tudományos Közleményei, ed 7DVVL * ʊ +HJHGĦV , ʊ .RYiFV 7 0ĦHJ\HWHPL Kiadó, Budapest, 2004, pp. 49-56., ISSN 1586-7196 Article in journal )ULHGPDQ 1 ʊ )DUNDV *\ Roof Structures in motion - on retractable and deployable roof structures enabling quick construction or adaption to external excitations, Concrete Structures, Vol. 12, ed.: Balázs, Gy. L., Hungarian Group of fib, Budapest, 21 pp. 41-50., 2011. )ULHGPDQ 1 ʊ )DUNDV *\ ʊ ,EUDKLPEHJRYLF $ Deployable/retractable structures towards sustainable development, Pollack Periodica, ed ,YiQ\L 0 ʊ ,YiQ\L $ $NDGpPLDL .LDGy Budapest, 12 p. (befogadva, kiadás alatt) )ULHGPDQ1ʊ)DUNDV*\ʊ,EUDKLPEHJRYLF$$]HVHUQ\ĘWĘOD]DGDSWtY-interaktív épületekig ʊ 1\LWKDWy-csukható rúdszerkezetek az építészetben, 0DJ\DU eStWĘLSDU 9RO 1R ed.: Antalffy, K., Budapest, pp. 67-73. 2011. Article in proceeding )ULHGPDQ1ʊ,EUDKLPEHJRYLF$ʊ)DUNDV*\ʊ'DYHQQH/Deployment analysis of an antiprismatic snap-through type cylindrical space truss and proposal for a pop-up bridge construction, Proceeding of the IASS-IACM 2012: Computational Mechanics for Spatial Structures (befogadva, kiadás alatt) )ULHGPDQ 1 ʊ ,EUDKLPEHJRYLF $ ʊ )DUNDV *\ ʊ 'DYHQQH / Quick Construction by Deployable Structures: A study on Deployable Structures Enabling a Quick Constructional Method, Proceeding of the NATO-ARW, 2008: Damage Assessment and Reconstruction After Natural Disasters and Previous Military Activities, Sarajevo, Bosznia-Hercegovina, 2008.09.052008.09.09, Springer, Dordrecht, Hollandia, pp. 315-321. 2008. )ULHGPDQ 1 ʊ )DUNDV *\ ÒMV]HUĦ N|QQ\ĦV]HUNH]HWHN .H]GHWL SUyEiONR]iVRN D] összehajtogatható szerkezetek általános mérnöki alkalmazására, ÉPKO 2005: IX. Nemzetközi eStWpVWXGRPiQ\L .RQIHUHQFLD (OĘDGiVDL, Csíksomlyó, Románia, 2005.06.03-2005.06.05., ed.: 18 Investigation of highly flexible, deployable structures: review, identification, control, application PhD thesis Noemi Friedman .|OOĘ*(UGpO\L0DJ\DU0ĦV]DNLTudományos Társaság, Kolozsvár, Románia , pp. 48-54., 2005., ISBN: 973-7840-05-4 Friedman, N.: $IDPLQWPRGHUQpStWĘDQ\DJ)DV]HUNH]HWHVFVDUQRNRNpVWHUYH]pVLHOYHLN, ÉPKO ;,1HP]HWN|]LeStWpVWXGRPiQ\L.RQIHUHQFLD(OĘDGiVDL, Csíksomlyó, Románia, 2003.05.29HG.|OOĘ*(UGpO\L0DJ\DU0ĦV]DNL7XGRPiQ\RV7iUVDViJ.ROR]VYiU5RPiQLD pp. 63-69., 2003., ISBN: 973-86097-3-9 Electronical publication )ULHGPDQ1ʊ+XV]iU=Vʊ.LVV50ʊ.OLQND.ʊ.RYiFV7ʊ9|OJ\L,Példatár a YDVEHWRQV]HUNH]HWHN , FtPĦ WDQWiUJ\KR], (electronic booklet), BME Hidak és Szerkezetek Tanszék, 2007., 110 p., ISBN 978-963-420-903-4, source: www.hsz.bme.hu/hsz/oktatas/feltoltesek/BMEEOHSAT18/vb1-gyakorlati_anyag.pdf )ULHGPDQ 1 ʊ .LVV 5 0 Kéttámaszú gerenda vasalása, gyakorlati segédlet a tervezési feladathoz, 26 p., 2009, source: www.hsz.bme.hu/hsz/oktatas/feltoltesek/BMEEOHSAT18/vb-1_tervezesi_feladat.pdf 19
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