Research project

Characterisation and modelling of adaptive structures

(Project B01 of the Collaborative research center SFB 1244)

Overview

  • Background
  • Characterization of adaptive structures
  • Modelling of the actuation

Project description

Background

Since the early 1970s, structures that can react automatically to a change in external loads or boundary conditions have been investigated in the USA. Mainly the aerospace industry was interested in these developments, as they lead to economic lightweight structures. In the last few years, sustainability and economical lightweight structures have played a major role in construction, which is why adaptive systems are becoming the focus of research. There are various application fields where adaptive systems offer efficient solutions. Mainly the aims are to influence design-decisive peak loads, to homogenize stress states and to reduce deformations.

Adaptivity of structures describes the ability to react automatically to a change in external loads or boundary conditions. This reaction can be carried out in various ways, e.g. changes of geometry, forces or material properties, which can be made by actuators. The control of the actuators requires a sensor system, which is able to detect the effects of the changes on the load-bearing structure. Thereupon a controlled reaction of the actuator system can be executed in order to configure the load-bearing structure optimally for the prevailing situation.

Stuttgarter Träger Adaptivity
Simulation of the "Stuttgarter Träger" (ILEK): Reduction of the vertical deformation under the single load by horizontal actuation of the right support. Passive state above, active state below.

Characterization of adaptive structures

Crucial for the work with adaptive systems is the definition of what an adaptive system exactly is. The required terminology, which is quite different in the fields of mechanical-, control- and civil-engineering, has to be brought together. In order to compare different designs, objective measures to value an adaptive system are needed. They can be calculated using redundancy contributions, gramian controllability matrices or similar. These matrices contain information, which can be used for an optimized placement of actuators in the structure. This is a crucial point in the assessment of the performance of an adaptive structure. Using a suitable actuator placement and control, e.g. stiffness-governed design tasks can be transferred into strength-governed tasks. For example, in the design of high-rise or wide spanned structures, the design decisive results can be deformations or accelerations in the structure. A well-designed adaptive structure is able to manipulate those quantities in order to reduce the amount of matter significantly, which is needed in the primary structure to comply with constraints.

Sizing passive vs active
Comparison of results for a sizing of the cross sections of a passive (left) and an adaptive Structure (right) subjected to the same load cases and constraints. The maximum utilizations of the cross sections (a) are larger in the adaptive structure, therefore smaller cross sections (b) are necessary, what leads to a lighter structure.

Modelling of the actuation

The focus in this research area is the modelling and simulation of adaptive systems. To carry out an exact analysis, which represents the behaviour of the adaptive structure realistically, the actuators, sensors and control technology must be integrated into the model. This is also beneficial in the development of algorithms that control the system. Towards an efficient simulation of adaptive structures using the finite element method, suitable finite actuator elements are defined.

Active truss element
Retracting active truss element.

Project data

Project title:
Teilprojekt B01 - Charakterisierung, Modellierung und Reduktion adaptiver Tragwerke
project webpage
Funding:

German Research Foundation (DFG), Collaborative Research Centre SFB 1244 "Adaptive Hüllen und Strukturen für die gebaute Umwelt von morgen", GEPRIS project number 324663295
Project partner:
Institute of Engineering and Computational Mechanics (ITM), University of Stuttgart


Publications

  1. 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, 94. https://doi.org/10.3389/fbuil.2020.00094
  2. Geiger, F., Gade, J., von Scheven, M., & Bischoff, M. (2020). Anwendung der Redundanzmatrix bei der Bewertung adaptiver Strukturen. Manfred Bischoff, Malte von Scheven, Bastian Oesterle (Hrsg.) Berichte der Fachtagung Baustatik – Baupraxis 14, 23. und 24. März 2020, Universität Stuttgart, 119–128. https://doi.org/10.18419/opus-10762
  3. Fröhlich, B., Gade, J., Geiger, F., Bischoff, M., & Eberhard, P. (2019). Geometric element parameterization and parametric model order reduction in finite element based shape optimization. Computational Mechanics, 63, 853–868. https://doi.org/10.1007/s00466-018-1626-1
  4. Wagner, J. L., Gade, J., Heidingsfeld, M., Geiger, F., von Scheven, M., Böhm, M., Bischoff, M., & Sawodny, O. (2018). On steady-state disturbance compensability for actuator placement in adaptive structures. at – Automatisierungstechnik, 66, 591–603. https://doi.org/10.1515/auto-2017-0099
  5. Weidner, S., Kelleter, C., Sternberg, P., Haase, W., Geiger, F., Burghardt, T., Honold, C., Wagner, J., Böhm, M., Bischoff, M., Sawodny, O., & Binz, H. (2018). The implementation of adaptive elements into an experimental high-rise building. Steel Construction, 11, 109–117. https://doi.org/10.1002/stco.201810019

Researcher:

This picture showsFlorian Geiger
M.Sc.

Florian Geiger

Scientific Staff

This picture showsJan Gade
M.Sc., B.Sc.

Jan Gade

Scientific Staff

This picture showsMalte von Scheven
Dr.-Ing.

Malte von Scheven

Deputy Head of Institute

To the top of the page