Abstract Torsion testing machines are widely used either to measure the strength, stiffness and stress-strain properties of materials or to replicate real-life service conditions. In this paper, a novel experimental method is presented, based on the development of a dedicated steel structure to be used in conjunction with a universal testing machine. This equipment allows applying cyclic in-plane torsion loads on disk-shaped components. The proposed approach aims to enable the assessment of stiffness and damping properties on specimens enabling the application of higher loads in comparison with the traditional machines. Specifically, dynamic trials were performed by attaching the composite specimens and the steel structure to the testing machine, such that the uniaxial controlled displacements can be used to exert the desired cyclic loads onto the specimen. Both torsional stiffness and energy loss were measured from the steady-state load-displacement hysteresis cycles. Amplitudes of sine signals, from 0.05 to 0.2 mm, and a frequency ranging between 1 and 20 Hz, were used in the experiments. The results are presented comparing the behaviour of two polymer matrix composites, with the same number of identical laminae, but characterized by different stacking sequences, namely unidirectional and quasi-isotropic configurations.

中文翻译：

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通过面内扭转试验评估圆盘形聚合物基复合材料试样的刚度和耗能性能

摘要 扭转试验机广泛用于测量材料的强度、刚度和应力应变特性，或复制现实生活中的使用条件。在本文中，基于与万能试验机结合使用的专用钢结构的开发，提出了一种新的实验方法。该设备允许在盘状部件上施加循环平面内扭转载荷。所提出的方法旨在评估试样的刚度和阻尼特性，从而与传统机器相比能够施加更高的载荷。具体来说，通过将复合试样和钢结构连接到试验机上进行动态试验，这样可以使用单轴受控位移将所需的循环载荷施加到试样上。扭转刚度和能量损失均通过稳态载荷-位移滞后循环进行测量。实验中使用的正弦信号幅度为 0.05 至 0.2 毫米，频率范围为 1 至 20 Hz。结果比较了两种聚合物基复合材料的行为，这些复合材料具有相同数量的相同层，但具有不同的堆叠顺序，即单向和准各向同性配置。