Non-contact strain measurement in the mouse forearm loading model using digital image correlation (DIC).
Non-contact strain measurement in the mouse forearm loading model using digital image correlation (DIC).
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DOI：
10.1016/j.bone.2015.09.007
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发表时间：
2015-12
期刊：
影响因子：
4.1
通讯作者：
Thiagarajan G
中科院分区：
文献类型：
--
作者：
Begonia MT;Dallas M;Vizcarra B;Liu Y;Johnson ML;Thiagarajan G
本研究使用一种称为数字图像相关(DIC)的非接触式方法来测量小鼠前臂在轴向压缩载荷下的应变。采用双摄像机系统同时分析前臂内侧和外侧的位移，并将得到的DIC应变测量结果与尺骨和桡骨的应变片读数进行比较。研究了感兴趣区域(ROI)位置、透镜放大率、噪声和离面运动等因素对DIC应变测量的影响。我们证实，我们的DIC系统可以区分ROI位置，因为它检测到尺骨的平均应变高于桡骨，并检测到内侧骨表面的压缩应变与外侧骨表面的拉伸应变。有趣的是，DIC方法还捕捉到了表面应变场中的非均质性，这是基于应变计的方法无法检测到的。对DIC系统固有噪声的单独分析也表明，噪声在所有DIC应变测量中所占的比例不到4.5%。此外，前臂的有限元(FE)模拟表明，平面外运动并不是影响DIC测量的重要因素。最后，我们观察到，平均DIC应变测量可以比内侧骨表面的平均应变片读数大1.5-2倍。这些发现表明，与应变片相比，通过DIC更好地捕捉到小鼠前臂模型中加载的应变，应变片由于粘在骨骼表面而人为地使骨骼僵硬，导致对应变响应的低估。
This study investigates the use of a non-contact method known as Digital Image Correlation (DIC) to measure strains in the mouse forearm during axial compressive loading. A two camera system was adapted to analyze the medial and lateral forearm displacements simultaneously, and the derived DIC strain measurements were compared to strain gage readings from both the ulna and radius. Factors such as region-of-interest (ROI) location, lens magnification, noise, and out-of-plane motion were examined to determine their influence on the DIC strain measurements. We confirmed that our DIC system can differentiate ROI locations since it detected higher average strains in the ulna compared to the radius and detected compressive strains on medial bone surfaces vs. tensile strains on lateral bone surfaces. Interestingly, the DIC method also captured heterogeneity in surface strain fields which are not detectable by strain gage based methods. A separate analysis of the noise intrinsic to the DIC system also revealed that the noise constituted less than 4.5% of all DIC strain measurements. Furthermore, finite element (FE) simulations of the forearm showed that out-of-plane motion was not a significant factor that influenced DIC measurements. Finally, we observed that average DIC strain measurements can be up to 1.5–2 times greater than average strain gage readings on the medial bone surfaces. These findings suggest that strain experienced in the mouse forearm model by loading is better captured through DIC as opposed to strain gages, which as a result of being glued to the bone surface artificially stiffen the bone and lead to an underestimation of the strain response.