Department of Structural Engineering, University of California-San Diego, La Jolla, CA 92093-0085, USA.
Material Science and Engineering Program, University of California-San Diego, La Jolla, CA 92093-0085, USA.
Sensors (Basel). 2018 Sep 9;18(9):3015. doi: 10.3390/s18093015.
The objective of this study was to develop a noncontact, noninvasive, imaging system for monitoring the strain and deformation states of osseointegrated prostheses. The proposed sensing methodology comprised of two parts. First, a passive thin film was designed such that its electrical permittivity increases in tandem with applied tensile loading and decreases while unloading. It was found that patterning the thin films could enhance their dielectric property's sensitivity to strain. The film can be deposited onto prosthesis surfaces as an external coating prior to implant. Second, an electrical capacitance tomography (ECT) measurement technique and reconstruction algorithm were implemented to capture strain-induced changes in the dielectric property of nanocomposite-coated prosthesis phantoms when subjected to different loading scenarios. The preliminary results showed that ECT, when coupled with strain-sensitive nanocomposites, could quantify the strain-induced changes in the dielectric property of thin film-coated prosthesis phantoms. The results suggested that ECT coupled with embedded thin films could serve as a new noncontact strain sensing method for scenarios when tethered strain sensors cannot be used or instrumented, especially in the case of osseointegrated prostheses.
本研究的目的是开发一种用于监测骨整合假体应变和变形状态的非接触、非侵入式成像系统。所提出的传感方法包括两部分。首先，设计了一种无源薄膜，使其介电常数随着拉伸载荷的施加而增加，随着卸载而减小。结果发现，对薄膜进行图案化可以提高其对应变的介电性能灵敏度。该薄膜可以在植入前作为外部涂层沉积在假体表面上。其次，实施了电容量层析成像 (ECT) 测量技术和重建算法，以捕获在不同加载情况下纳米复合涂层假体模型的介电性能因应变而产生的变化。初步结果表明，ECT 与应变敏感型纳米复合材料结合使用时，可以定量测量薄膜涂层假体模型因应变而引起的介电性能变化。结果表明，ECT 与嵌入式薄膜结合使用，可以作为一种新的非接触应变传感方法，用于无法使用或无法进行应变传感器测量的情况，特别是在骨整合假体的情况下。
