Abstract A bistable composite tape-spring (CTS) is stable in both the extended and coiled configurations, with fibres oriented at ±45°. It is light weight and multifunctional, and has attracted growing interest in shape-adaptive and energy harvesting systems in defence-, civil- and, especially aerospace engineering. The factors governing its bistability have been well-understood, but there is limited research concerning the mechanics of structural failure: here, we investigate the shear failure mechanisms in particular. We perform in-situ neutron diffraction on composite specimens using the ENGIN-X neutron diffractometer at Rutherford Appleton Laboratory (STFC, UK), and shear failure is characterised at both macroscopic and microscopic scales. Elastic and viscoelastic strain evolutions at different strain levels reveal the fundamentals of micromechanical shear failure, and their temperature dependency. Multiscale shear failure mechanisms are then proposed, which will benefit the optimisation of structural design to maintain structural integrity of CTS in aerospace applications.

中文翻译：

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双稳态复合带弹簧的原位多尺度剪切破坏

摘要 双稳态复合带弹簧 (CTS) 在拉伸和盘绕配置中都很稳定，纤维取向为 ±45°。它重量轻、功能多，并且在国防、土木和特别是航空航天工程中的形状自适应和能量收集系统引起了越来越多的兴趣。控制其双稳态的因素已被很好地理解，但关于结构破坏力学的研究有限：在这里，我们特别研究了剪切破坏机制。我们使用 Rutherford Appleton 实验室（STFC，英国）的 ENGIN-X 中子衍射仪对复合样品进行原位中子衍射，并在宏观和微观尺度上表征剪切破坏。不同应变水平下的弹性和粘弹性应变演变揭示了微机械剪切破坏的基本原理及其温度依赖性。然后提出了多尺度剪切破坏机制，这将有利于结构设计的优化，以保持 CTS 在航空航天应用中的结构完整性。