Introduction
Adaptive structures can be defined as structures designed to respond continuously and automatically to changes in the environment that are actuated by variations in temperature and other environmental conditions that affect the internal structure of civil engineering materials. This technology is most important for civil engineering structures in this modern age owing in part to the emissions that lead to more glaring and negative impacts on the stability of the climate as well as the shortage of civil engineering materials (Geiger, 2020).
Adaptive structures consist of the marriage of two design principles that have guided civil engineering designs for the time being. The first principle ensures that strength is designed into buildings in order to prevent collapse while the second principle which is applicable in most modern design codes ensures that structures and designed and built to be stiff enough to resist all forces or loads that would arise from external influences such as vehicle loads on bridges, gathering of large crowds, wind loads, earthquake loads, etc (The Construction Wiki, 2022). These afore-mentioned design principles often required the incorporation of heavy loads and high strength materials into structures which cost a lot of money and materials and constitute many loads in addition to environmental impacts.
Adaptive structures in contrast to conventional systems (described in the first two principles) try to divulge these two principles through the creation of structures that consists both of materials (conventional materials) and movement control systems. In essence, there should be room for the structure to respond to forces through movements without collapsing. Take for instance, when a heavy wind is blowing through a slender tree, we would notice that the tree would bend in response to the wind force which in effect reduces the impact of the wind force on the tree. The conventional materials in adaptive structures provide for safety while the control systems provide means by which the structures can move in response to loads or change their shapes under loads thereby reducing the impact of the load or force on the structure. Achieving this requires the creation of slender designs that require less materials consumption and less cost.
Importance of Adaptive Structures
- There would be savings in cost and materials when using adaptive structures.
- Construction time for adaptive structures would likely be less than for conventional structures.
- Less environmental impact would be expected when using adaptive structures because of less use of materials and less embodied energy released.
- Adaptive structures would reduce many fears associated with the environmental and ecological effects associated with climate change.
- It helps to reduce enormous waste arising from building construction and demolition.
- It ensures more efficient use of materials because the adverse conditions against which conventional design principles often apply are not always constant.
Disadvantages of Adaptive Structures
- Unlike conventional buildings, it requires influences from architecture, structural engineering, mechanical engineering, and control engineering to be properly integrated to design an optimal adaptive structure.
- When in operation, adaptive structures require power to keep the control system in operation. Therefore, a power outage could present a risk to the inhabitants.
Applications of Adaptive Structures
Adaptive structures can be applicable in the design and construction of high-rise buildings, portal frames, wide-span structures such as roofs or arch bridges, vaults, etc.
How to Achieve Adaptive Structures
Adaptive structure cannot be possible without artificial intelligence. In addition to the conventional materials (passive elements), the structures would contain actuators, sensors, and control intelligence that would have the capacity to control the load-bearing and deformation behaviour of the entire structure and thus helps to counter loads without user intervention or predetermined knowledge of external loads.
In adaptive structures, the strength of the materials used is very important. Thus, this should be thoroughly investigated since the structure is no longer standing as a common stiff unit. There should also be a thorough understanding of how to place actuators (Geiger et al, 2020a). A number of studies have been done previously that are pointing toward the future of adaptive structures (Kirsch and Moses, 1977; Hale et al., 1985; Kawaguchi et al. 1996; Senatore et al. 2017; Wagner et al., 2018 and Senotore et al. 2019). However, the most recent research by Geiger (2020) showed that it is possible to design passive structures and make them adaptive afterward with the proper introduction of the optimal number and location of actuators. With significant mass savings of as much as 65% observed when using adaptive structures for trusses and frames in buildings instead of conventional materials, the most important task now is to learn properly how to place actuators to ensure they understand how to respond to loads and variations of loads. There is also the importance of learning how to determine a single integral design process for adaptive structures without having to first go through the conventional structures design process.
Further Reading
Geiger, F., Gade, J., von Scheven, M., and Bischoff, M. (2020a). “Anwendung der Redundanzmatrix bei der Bewertung adaptiver Strukturen [Application of the redundancy matrix in the assessment of adaptive stuctures],” in Baustatik-Baupraxis, eds B. Oesterle, M. von Scheven, and M. Bischoff, Vol. 14 (Stuttgart: Institute for Structural Mechanics, University of Stuttgart), 119–128.
Geiger, F., Gade, J., von Scheven, M., & Bischoff, M. (2020). A Case Study on Design and Optimization of Adaptive Civil Structures. Frontiers in Built Environment, 6, 548153. https://doi.org/10.3389/fbuil.2020.00094
Hale, A. L., Lisowski, R. J., and Dahl, W. E. (1985). Optimal simultaneous structural and control design of maneuvering flexible spacecraft. J. Guid. Control Dyn. 8, 86–93. doi: 10.2514/3.19939
Kawaguchi, K.-I., Hangai, Y., Pellegrino, S., and Furuya, H. (1996). Shape and stress control analysis of prestressed truss structures. J. Reinf. Plast. Compos. 15, 1226–1236. doi: 10.1177/073168449601501204
Kirsch, U., and Moses, F. (1977). Optimization of structures with control forces and displacements. Eng. Optim. 3, 37–44. doi: 10.1080/03052157708902375
Senatore, G., Duffour, P., Winslow, P., and Wise, C. (2017). Shape control and whole-life energy assessment of an ‘infinitely stiff’ prototype adaptive structure. Smart Mater. Struct. 27:015022. doi: 10.1088/1361-665X/aa8cb8
Senatore, G., Duffour, P., and Winslow, P. (2019). Synthesis of minimum energy adaptive structures. Struct. Multidiscipl. Optim. 60, 849–877. doi: 10.1007/s00158-019-02224-8
The Construction Wiki (2022). Adaptive structures. Retrieved on 26th July, 2023. URL: https://www.designingbuildings.co.uk/wiki/Adaptive_structures
