Adaptive composites with embedded shape memory alloy wires

• Research unit: EU RFP
• Project number: 97.0450

Key words (English)

Shape memory alloys; composites; adaptive; vibration control

Alternative project number (English)

EU project number: BE97-4134

Research programs (English)

EU-programme: 4. Frame Research Programme - 2.1 Industrial and materials technologies

Short description (English)

See abstract

Partners and International Organizations (English)

Katholieke Universiteit Leuven, Department of Metallurgy and Materials Engineering (B), Institute of Chemical Engineering and High Temperature Chemical Processes (EL), Daimler-Chrysler Aerospace (D), British Aerospace( UK), EADS Deutschland GmbH, Military Aircraft (D)

Abstract (English)

The general objective of this European basic research project is the development and characterisation of new materials integrating thin shape-memory-alloy (SMA)-wires as actuating elements in fibre reinforced polymer matrix composites. This new material will allow the variation of its stiffness and vibration frequency in a controlled way. All steps from the selection and characterisation of the material constituents up to the development of simple, larger-scale laboratory models are followed in this project. Substantial progress, far beyond the knowledge available in literature, has been achieved. This resulted in large amount of scientific publications and the development of an actual SMA composite aerodynamic scale model.
The 'Ecole Polytechnique Fédérale de Lausanne, (EPFL)' has contributed during the whole period of the project to all main tasks:
In task 1, which concentrates on the selection and characterisation of the material constituents and mainly finished in the first half of the project, substantial knowledge of the curing process and the SMA wire resin interface was gained. SEM-studies of the surface of different types of wires have been carried at EPFL and are shown in the ADAPT Web-pages. They show always a more or less rough structure consisting of nickel and titanium oxides. For the characterisation of the resin the following techniques have been applied: differential scanning calorimetry to study the curing process, rheological dynamic analysis to determine viscosity, dynamic mechanical analysis for the mechanical properties and thermal expansion measurements
In task 2, EPFL has strongly contibuted to the production and characterisation of SMA composites. EPFL has developed and tested an experimental set-up consisting of a metallic frame, which allows the SMA-wires to be prestrained and maintains them strained during the curing process. SMA composites with different geometrical and functional properties can be produced. This frame has been sent to the British partner who was responsible for the production of different types of the new composites for all partners. An experimental set-up has been developed, constructed and tested at EPFL to measure the change of vibration frequency of the SMA-composites after activation of the SMA-wires. As expected, a displacement of the frequency towards higher values has been observed. This is one of the main milestones of the project. The wide range of experiments indicated that the overall quality of the produced SMA composites is good.
The prediction of the thermomechanical and functional properties of SMA composites was investigated in task 3.The different models developed correspond very well with the experimental results of task 2. This proves the quality of the modelling and provides a powerful tool for the prediction of the behaviour of SMA composites and applications.
The final step towards an application has been taken by the development of a demonstrator in task 4. An actual model of an aerodynamic profile has been built and tested. This realisation proves that the achievements of tasks 1 to 3 have brought the knowledge on SMA composites to a substantially higher level enabling a first step towards an industrial application.
At the end of this project it can be said that the research of SMA composites has taken a big step forward and that the project consortium owns valuable knowledge.
All results are collected in a common database, which can be consulted by all partners on protected Web-pages.
EPFL was the organiser of two of the regularly planned meetings of the partners.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 97.0450