Formica Giovanni, Lacarbonara Walter, Yabuno Hiroshi
Department of Architecture, Roma Tre University, 33328 Rome, Italy.
Department of Structural and Geotechnical Engineering, Sapienza University of Rome, 33328 Rome, Italy.
Nanomaterials (Basel). 2023 Jun 5;13(11):1808. doi: 10.3390/nano13111808.
A nonlinear MEMS multimass sensor is numerically investigated, designed as a single input-single output (SISO) system consisting of an array of nonlinear microcantilevers clamped to a shuttle mass which, in turn, is constrained by a linear spring and a dashpot. The microcantilevers are made of a nanostructured material, a polymeric hosting matrix reinforced by aligned carbon nanotubes (CNT). The linear as well as the nonlinear detection capabilities of the device are explored by computing the shifts of the frequency response peaks caused by the mass deposition onto one or more microcantilever tips. The frequency response curves of the device are obtained by a pathfollowing algorithm applied to the reduced-order model of the system. The microcantilevers are described by a nonlinear Euler-Bernoulli inextensible beam theory, which is enriched by a meso-scale constitutive law of the nanocomposite. In particular, the microcantilever constitutive law depends on the CNT volume fraction suitably used for each cantilever to tune the frequency bandwidth of the whole device. Through an extensive numerical campaign, the mass sensor sensitivity estimated in the linear and nonlinear dynamic range shows that, for relatively large displacements, the accuracy of the added mass detectability can be improved due to the larger nonlinear frequency shifts at resonance (up to 12%).
对一种非线性微机电系统多质量传感器进行了数值研究，该传感器设计为单输入单输出（SISO）系统，由一系列非线性微悬臂梁组成，这些微悬臂梁固定在一个穿梭质量块上，而穿梭质量块又由一个线性弹簧和一个阻尼器约束。微悬臂梁由一种纳米结构材料制成，即由排列的碳纳米管（CNT）增强的聚合物主体基质。通过计算质量沉积到一个或多个微悬臂梁尖端引起的频率响应峰值的偏移，来探索该器件的线性和非线性检测能力。该器件的频率响应曲线通过应用于系统降阶模型的路径跟踪算法获得。微悬臂梁由非线性欧拉 - 伯努利不可伸长梁理论描述，并通过纳米复合材料的细观尺度本构定律进行了补充。特别地，微悬臂梁的本构定律取决于为每个悬臂梁适当使用的碳纳米管体积分数，以调整整个器件的频率带宽。通过广泛的数值研究，在线性和非线性动态范围内估计的质量传感器灵敏度表明，对于相对较大的位移，由于共振时较大的非线性频率偏移（高达12%），可以提高附加质量可检测性的精度。
