Abstract In this work, we report on the fabrication and characterization of a buckling system constituted by square array holes able to modify its structural configuration and its optical response as a function of the applied force. Herein, polydimethylsiloxane (PDMS) auxetic structures are fabricated by means of 3D printing mold and casting/peeling off steps. From a mechanical point of view, it has been demonstrated that the structure presents a transformation to a strikingly different pattern of alternating mutually orthogonal ellipses above a nominal force of 23 N, a clear signature of the auxetic structures behavior. This feature has been exploited to create a reversible and sensitive optical force sensor, that makes use of the variation on the light intensity or its optical rotation (θ) upon application of a force. In fact, it has been demonstrated that the application of the force induces a variation of the refractive index of the auxetic system, associated to the presence of stress. For the structure realized a sensitivity of about Δ ( Δ θ ) Δ F = 0.033 rad/N in the range between 23 N and 28 N has been determined. Finally, the presented study suggests that it is possible to realize a sensitive and reversible optical force sensor taking advantages of the peculiar features of buckling periodic elastic materials.

中文翻译：

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评估作为光学力传感器的屈曲周期弹性材料的机械和光学性能

摘要 在这项工作中，我们报告了由方形阵列孔构成的屈曲系统的制造和表征，该系统能够根据所施加的力来修改其结构配置和光学响应。在此，聚二甲基硅氧烷 (PDMS) 拉胀结构是通过 3D 打印模具和浇铸/剥离步骤制造的。从力学的角度来看，已经证明该结构在 23 N 的标称力之上呈现出显着不同的交替相互正交椭圆模式的转变，这是拉胀结构行为的明显特征。该特征已被用于创建可逆且灵敏的光学力传感器，该传感器利用施加力时光强度或其旋光度 (θ) 的变化。实际上，已经证明，施加力会导致拉胀系统的折射率发生变化，这与应力的存在有关。对于实现的结构，在 23 N 和 28 N 之间的范围内确定了大约 Δ ( Δ θ ) Δ F = 0.033 rad/N 的灵敏度。最后，所提出的研究表明，利用屈曲周期弹性材料的特殊特性，可以实现灵敏且可逆的光学力传感器。