Development of Shape Memory-Based Elastic-Adaptive Damping Elements for Sport and Rehabilitation Equipment

Abstract

Abstract The generation and variation of forces necessary to achieve a training stimulus is often realized in sports and rehabilitation equipment by manually adjustable masses or by complex motor-brake systems. This leads to heavy and unwieldy systems, which cannot be used flexibly, and in addition to high costs. The main objective of this paper is to prove that pseudoelastic shape memory alloys (SMA) are potentially suitable for use in sports and rehabilitation equipment and offer additional value in the area of training flexibility combined with high training resistance. Therefore, the properties of pseudoelastic SMAs for this application were investigated. These multifunctional materials offer the potential for special elastic and sensory properties. The pseudoelastic effect is based on stress-induced martensite formation, which allows high elastic deformations. During this phase transformation, the mechanical stress passes through a plateau. The stress plateau can be moved by changing the temperature of the SMA. The determination of properties of pseudoelastic SMAs with different alloy compositions was carried out according to the specifications of “VDI 2248: Product Development with Shape Memory Technology”. With a functional model based on the material tests, which replaces a commercially available force clamping device, the monitoring of force, displacement and temperature changes can be realized by the integrated sensor technology. This paper presents the methodology, experiments and findings for the use of pseudoelastic SMAs in sport and rehabilitation devices. It concludes with prospects to commercial application.