Takahashi Azuma, Suzuki Sara, Aoyama Yusuke, Umezu Mitsuo, Iwasaki Kiyotaka
Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo, Japan.
Department of Modern Mechanical Engineering, Graduate School of Creative Science and Engineering, Waseda University, Shinjuku, Tokyo, Japan.
PLoS One. 2017 Sep 14;12(9):e0184782. doi: 10.1371/journal.pone.0184782. eCollection 2017.
The mechanical interaction between blood vessels and medical devices can induce strains in these vessels. Measuring and understanding these strains is necessary to identify the causes of vascular complications. This study develops a method to measure the three-dimensional (3D) distribution of strain using tomographic particle image velocimetry (Tomo-PIV) and compares the measurement accuracy with the gauge strain in tensile tests.
The test system for measuring 3D strain distribution consists of two cameras, a laser, a universal testing machine, an acrylic chamber with a glycerol water solution for adjusting the refractive index with the silicone, and dumbbell-shaped specimens mixed with fluorescent tracer particles. 3D images of the particles were reconstructed from 2D images using a multiplicative algebraic reconstruction technique (MART) and motion tracking enhancement. Distributions of the 3D displacements were calculated using a digital volume correlation. To evaluate the accuracy of the measurement method in terms of particle density and interrogation voxel size, the gauge strain and one of the two cameras for Tomo-PIV were used as a video-extensometer in the tensile test. The results show that the optimal particle density and interrogation voxel size are 0.014 particles per pixel and 40 × 40 × 40 voxels with a 75% overlap. The maximum measurement error was maintained at less than 2.5% in the 4-mm-wide region of the specimen.
We successfully developed a method to experimentally measure 3D strain distribution in an elastic silicone material using Tomo-PIV and fluorescent particles. To the best of our knowledge, this is the first report that applies Tomo-PIV to investigate 3D strain measurements in elastic materials with large deformation and validates the measurement accuracy.
血管与医疗设备之间的机械相互作用可在这些血管中诱发应变。测量和了解这些应变对于确定血管并发症的原因至关重要。本研究开发了一种使用断层粒子图像测速技术（Tomo-PIV）测量应变三维（3D）分布的方法，并将测量精度与拉伸试验中的应变片应变进行比较。
用于测量3D应变分布的测试系统由两台相机、一台激光器、一台万能试验机、一个装有甘油水溶液以调节与硅胶折射率的丙烯酸腔室以及与荧光示踪粒子混合的哑铃形试样组成。使用乘法代数重建技术（MART）和运动跟踪增强技术从二维图像重建粒子的三维图像。使用数字体积相关计算三维位移的分布。为了从粒子密度和询问体素大小方面评估测量方法的准确性，在拉伸试验中将应变片应变和Tomo-PIV的两台相机之一用作视频引伸计。结果表明，最佳粒子密度和询问体素大小分别为每像素0.014个粒子和40×40×40体素，重叠率为75%。在试样4毫米宽的区域内，最大测量误差保持在2.5%以下。
我们成功开发了一种使用Tomo-PIV和荧光粒子通过实验测量弹性硅胶材料中3D应变分布的方法。据我们所知，这是第一篇应用Tomo-PIV研究大变形弹性材料中3D应变测量并验证测量精度的报告。
