Structural Adaptation through Large Shape Changes


This research builds upon the work on Minimum Energy Adaptive Structures to further investigate structure-control design strategies with the objective to improve structural performance as well as to reduce environmental impacts with respect to conventional passive structures.

The main contribution of this research is in the development and testing of new computational methods to design and control structures that able to adapt to loading through large shape reconfigurations involving geometrically non-linear effects. The design methodology that has been developed though this research comprises two stages. In stage 1 the structure is designed through sizing and geometry optimization to be able to morph into optimal shape configurations as the load changes. In stage 2, the actuator placement is optimized so that the structure can be controlled into the target shapes obtained in stage 1. The design criterion employed to coordinate stage 1 and stage 2 is minimization of whole-life energy (or equivalent carbon) which comprises a part embodied in the material and an operational part for sensing, control and actuation during service (see Minimum Energy Adaptive Structures).

Experimental testing has been carried out on 6.6m (length) x 1m (width) x 0.16m (depth) simply supported truss equipped with 12 linear actuators, strain gauges and an optical tracking system. This configuration can be thought of a scaled version of a footbridge or a roof system. The optimal/target geometry is computed in real-time through shape optimization as the load changes. Then, commands are determined to control the structure into the target shape which requires solving an inverse problem in real-time. The mechanics-based control algorithm developed in this work enables accurate shape adaptation using minimum computational cost, which makes it suitable for real-time applications.

Numerical and experimental testing have shown that structures that adapt to loading through large shape changes achieve marginal whole‐life energy savings with respect to structures that adapt to loading through small shape changes (see Minimum Energy Adaptive Structures). However, the ability to adapt into a shape that is optimal to counteract the effect of loading, enables effective stress homogenization which results in significant embodied energy (material mass or equivalent carbon) savings with respect to weight‐optimized passive structures as well as to structures that adapt through small shape changes.

The design strategy developed though this research is effective when operational energy is not of primary concern, for example if supplied from renewable sources. The deferral of energy usage obtained by replacing a large embodied share with an operational share, reduces life-cycle emissions because environmental impact costs of energy production will reduce in the future owing to technological advancements.

 

Acknowledgments

Gennaro Senatore has led this research during his time at Swiss Federal Institute of Technology (EPFL) in Lausanne. This work has been generously funded by: Swiss National Science Foundation, Arup and Mero Structures.

Team

Gennaro Senatore (Director)
Ian Smith (Director)
Arka Reksowardojo (PhD student) | Swiss Federal Institute of Technology (EPFL)
Chris Carroll, Henry Unterreiner | Arup UK

 

Publications

A. P. Reksowardojo, G. Senatore and I. F. C. Smith, “Design of structures that adapt to loads through large shape changes,” The Journal of Structural Engineering (ASCE), vol. 146, no. 5, p. 04020068, 2020.
DOI: https://doi.org/10.1061/(ASCE)ST.1943-541X.0002604

A. P. Reksowardojo, G. Senatore and I. F. C. Smith, “Experimental testing of a small-scale truss beam that adapts to loads through large shape changes,” Frontiers in Built Environment, vol. 5, no. 93, 2019.
DOI: https://doi.org/10.3389/fbuil.2019.00093

A. P. Reksowardojo and G. Senatore, “A proof of equivalence of two force methods for active structural control,” Mechanics Research Communications, vol. 103, p. 103465, 2020.
DOI: https://doi.org/10.1016/j.mechrescom.2019.103465

 

 

1 / 8