Kirkpatrick S J, Duncan D D
Department of Oral Biology, University of Nebraska Medical Center, College of Dentistry, Lincoln 68583-0740, USA.
J Biomed Mater Res. 1995 Nov;29(11):1437-42. doi: 10.1002/jbm.820291115.
A technique is presented that allows for highly sensitive and highly accurate measurements of microstrain in biomaterials. It is particularly useful for measuring strains in materials where the use of conventional extensometers or strain gauges is impracticable, such as reinforcement fibers and orthodontic wires and in hostile environments. The technique is based on the well known technique of observing translating laser speckle with a linear-array charge-coupled device (CCD) camera. However, it employs a relatively new data processing algorithm involving a two-dimensional frequency transform of the data. Advantages of the technique include: insensitivity to slow surface microstructure changes, insensitivity to zero-mean noise processes, compact design, modest resolution requirements, and the fact that it is truly noncontact. Strain rate measurements were made on an 0.028-gauge round stainless steel orthodontic wire as an example of this technique. The Young's modulus of the wire based on the speckle technique was 2.04 x 10(11) Nm(-2), which is very close to the textbook value.
本文介绍了一种能够对生物材料中的微应变进行高灵敏度和高精度测量的技术。该技术对于测量那些使用传统引伸计或应变片不可行的材料中的应变尤为有用，比如增强纤维、正畸钢丝以及在恶劣环境中的材料。该技术基于一种众所周知的技术，即使用线性阵列电荷耦合器件（CCD）相机观察移动的激光散斑。然而，它采用了一种相对较新的数据处理算法，该算法涉及数据的二维频率变换。该技术的优点包括：对缓慢的表面微观结构变化不敏感、对零均值噪声过程不敏感、设计紧凑、分辨率要求适中，以及它是真正的非接触式测量。作为该技术的一个例子，对一根0.028规格的圆形不锈钢正畸钢丝进行了应变速率测量。基于散斑技术测得的钢丝杨氏模量为2.04×10¹¹ Nm⁻²，这与教科书上的值非常接近。
