Design and analysis of scissors structures for mobile architectural applications.

Project Details

Description

Structures that can adapt their shape to respond to changing circumstances, or that can be quickly and easily deployed to perform their architectural function and removed afterwards without damaging sensitive sites, are well-equipped to meet the demands of a rapidly changing society which embraces the concept of sustainable design. Although the research subject of deployable structures is relatively young, the principle of transformable objects and spaces has been applied throughout history (the Mongolian yurt, the velum of the Roman Coliseum). Nowadays, the main application areas are the aerospace industry, requiring highly compactable, lightweight payload (solar arrays), and architecture, requiring either fixed-location retractable roofs for sports arenas (Wimbledon) or mobile, lightweight temporary shelters (emergency tents) [1].
Mobile shelter systems are a type of structure for which there is a vast range and diversity of forms and structural solutions. They are designed to provide weather protected enclosure for a wide range of human activities (emergency shelters after natural disasters, exhibition and recreational structures, temporary buildings in remote construction sites and relocatable hangars and maintenance facilities). Enclosure requirements are generally very simple, with the majority needing only a weather protecting membrane supported by some form of erectable structure. In all applications, both the envelope and structure need to be capable of being easily moved in the course of normal use, which very often requires the building system to be assembled at high speed, on unprepared sites [2]. For this purpose, scissor structures are highly effective: besides being transportable, they have the great advantage of speed and ease of erection and dismantling, while offering a huge volume expansion [3]. Scissor structures consist of scissor units, also called scissor-like elements (SLE's). These consist of two straight beams connected through a revolute joint, the intermediate hinge, allowing a relative rotation, but at the same time introducing bending moments in the beams. By connecting such SLE's at their end nodes by hinges, a three-dimensional grid structure is formed, which can be transformed from a compact bundle of elements to a fully deployed configuration. Finally, by adding constraints, the mechanism is converted into a structure.

Although many different deployable systems have been proposed, few have successfully found their way into the field of temporary constructions. A cause for this can be found in the complexity of the design process and their sensitivity to geometric imperfections, an issue which may be more easily tackled in aerospace related applications, where the loading conditions are completely different [4-6]. The joints, which ensure the expansion of the structure during the deployment process, require careful and detailed design. Also, designing deployable structures requires a thorough understanding of the specific 2D and 3D configurations which will give rise to a fully deployable geometry. The key element is that there is a direct and mutual relationship between the geometry and the kinematic and structural response of the scissor system, both during deployment and in the final deployed state.

For architectural engineering applications, subtle and inevitable changes in the scissor geometry (manufacturing and assembly tolerances, hinge position, beam length, straight or curved beams) can have a dramatic effect on the final deployed shape (architectural performance) and on the deployment phase (input force, deformation). This can result in undesired behaviour or no deployment at all, thereby prohibiting the structure from fully performing its architectural function.

AcronymIWT533
StatusFinished
Effective start/end date1/01/1131/12/14

Keywords

  • Social Highrise
  • Truss Design
  • Design methods
  • Theory of architecture
  • Architecture
  • Social housing
  • Social highrise
  • Design education
  • Tensile structures
  • Education
  • Engineering
  • Harmonic Progression
  • Renovation
  • Formfinding
  • Building technology
  • renovation
  • Fire engineering

Flemish discipline codes

  • Civil and building engineering
  • Materials engineering