Thermo-mechanical de-icing

清除空气动力表面的结冰是航空领域的一项常见挑战，这危及飞行安全。另一方面，冰沉积也是地面固定设施的一个问题，例如风力涡轮机。为了解决这个问题，特别是对于采用纤维复合材料的现代轻质建筑来说，一种新的除冰概念正在被开发出来。这一概念基于形状记忆合金(SMA)的工作原理。环形形状的SMA丝嵌入弹性体中。合金被加热激活，导致环收缩。由此产生的收缩会使弹性体膨胀。热激活的热还会增加表面温度，从而降低粘接强度。通过叠加机械效应(膨胀)和热效应(温度升高)，沉积的冰将更容易和有效地被清除。如果加热中断，SMA焊丝不再活动并冷却。由于弹性体的弹性力，SMA钢丝在相变后会变形回初始位置。本项目的目的是从功能一致性的角度详细研究热机械除冰系统的概念。在新的除冰原理中，弹性体和SMA必须和谐地相互作用。由于SMA独特的热和力学耦合特性，SMA提供了一种天然的混合式除冰系统。通过这个项目，我们希望彻底调查影响性能的机制。这包括改善个别影响参数，如弹性体导热系数和刚度，提高形状记忆合金的工作频率。此外，还将在气动载荷下研究新的功能模型。

The removal of ice deposits on aerodynamic surfaces is a frequent challenge in aviation, which jeopardises flight safety. On the other hand, ice deposition is also a concern for stationary installations on the ground, such as wind turbines. To solve this problem, especially for modern lightweight construction with fibre composites, a novel de-icing concept is being developed. The concept is based on the working principle of shape memory alloys (SMA). The ring-shaped SMA wire is embedded in an elastomer. The alloy is activated by heat, causing the ring to contract. The contraction thus produced causes the elastomer to bulge. The heat of the thermal activation additionally increases the surface temperature and thus reduces the adhesive strength. By superimposing the mechanical (bulging) and thermal effect (temperature increase), the deposited ice is to be removed more easily and efficiently. If the heating is interrupted, the SMA wire is no longer active and cools down. Due to the spring force of the elastomer, the SMA wire deforms back to its initial position after the phase transformation.The aim of this project is to investigate in detail the concept for a thermo-mechanical de-icing system with regard to functional conformity. The elastomer and SMA must interact harmoniously in the new de-icing principle. This requires the temporal and spatial coupling of thermal and mechanical effects.Due to the unique coupled thermal and mechanical properties, SMA offers a natural hybrid de-icing system. With this project we want to thoroughly investigate the mechanisms that influence performance. This includes the improvement of individual influencing parameters such as the thermal conductivity and stiffness of the elastomer, the increase of the working frequency of the SMA. Furthermore, the new functional models will be investigated under aerodynamic load.