Non-Destructive Testing of Industrial Materials Using Inverse Techniques

使用逆向技术对工业材料进行无损检测

• 批准号: RGPIN-2014-06015
• 负责人: Schajer, Gary
• 金额: $ 2.4万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=588756
• 关键词: Non; Destructive; Testing; Industrial; Materials

Industrial quality control testing works straightforwardly when the quantity of interest can be measured independently. However, practical measurements often combine several quantities that then need to be separated. This can be done by using an “inverse” calculation. The “forward” calculation would be to sum all the target quantities, if they were known, to determine the combined measurement that would be made. The inverse calculation separates the various quantities and is much more difficult and mathematically sensitive. The two applications of inverse calculations explored here differ physically but they share substantial mathematical commonality and complementary features. Log Sorting in Sawmills using X-Ray Computed Tomography: To compete effectively in the international market, Canadian sawmills must produce the highest value products from the available raw material. This can be done by examining each log entering a sawmill, and strategically processing it for the highest value product. This sorting must be done well, else substantial wastage will occur either as high-quality material getting used for low-value products, or low-quality material failing to make high-value products. X-ray Computed Tomography (CT) provides a promising way to identify the quality-controlling interior features of logs. CT measurements are well established in the medical field, but are not well suited for industrial use in sawmills because of their complexity, cost and mechanical sensitivity. Work has been ongoing here to develop a simplified, economical and rugged CT scanner design. The key to the approach taken is the observation that the measured logs and their internal features have very specific geometries, for example, logs are cylindrical, heartwood and sapwood are arranged axi-symmetrically, and knots are arranged radially. Thus, a specialized CT inversion scheme can be developed to take advantage of this advance information and thereby reduce the demand on both required measurement accuracy and computational size. Very promising results have been obtained in laboratory tests, and the present proposal is directed towards further functional developments such as spiral scanning and to practical demonstrations. Practical Residual Stress Measurement in Industrial Components: Residual stresses are locked-in stresses that exist in materials without the presence of any external loads. These stresses are important because they significantly affect the dimensional stability and material strength of industrial components. If not detected and controlled in manufacturing processes, substantial material wastage premature product failures can occur. The “hidden” character of residual stresses makes them difficult to measure reliably and requires the use of “inverse” evaluations. Residual stress measurements are typically done by measuring the deformations that occur when some stressed material is removed, for example, by drilling a small hole. Optical techniques such as Digital Image Correlation (DIC) and Electronic Speckle Pattern Interferometry (ESPI) are attractive measurement techniques because they are non-contact, rapid and economical. They provide full-field optical data that allow sophisticated interpretation significantly beyond the more typical minimal data measurement approaches. Traditionally, DIC and ESPI have used monochromatic light. The proposed research is aimed at exploiting the larger data content available in multi-colour optical measurements. This allows 3-D deformation identifications from nominally 2-D data and enables more sophisticated evaluations of residual stresses, including some out-of-plane stress components that are not available with present measurement techniques.

当感兴趣的量可以独立测量时，工业质量控制测试可以直接进行。然而，实际测量通常将联合收割机的几个量结合起来，然后需要将其分离。这可以通过使用“逆”计算来完成。“向前”计算将是对所有目标量（如果它们是已知的）求和，以确定将进行的组合测量。逆计算将各个量分开，并且更加困难和数学敏感。这里探讨的逆计算的两种应用在物理上不同，但它们具有大量的数学共性和互补特征。 使用X射线计算机断层扫描仪在锯木厂进行原木分选： 为了在国际市场上有效竞争，加拿大锯木厂必须从现有的原材料中生产出最高价值的产品。这可以通过检查进入锯木厂的每根原木来完成，并战略性地加工它以获得最高价值的产品。这种分类必须做得很好，否则就会出现大量的浪费，因为高质量的材料被用于低价值的产品，或者低质量的材料不能制造高价值的产品。 X射线计算机断层扫描（CT）技术为原木质量控制性内部特征的识别提供了一种有效的方法。CT测量在医学领域已经得到了很好的应用，但由于其复杂性、成本和机械敏感性，并不适合在锯木厂中的工业应用。目前正在开发一种简化、经济和坚固的CT扫描仪设计。所采取方法的关键是观察到所测量的原木及其内部特征具有非常特定的几何形状，例如，原木是圆柱形的，心材和边材轴对称排列，节是径向排列的。因此，可以开发专门的CT反演方案以利用这种先进信息，从而降低对所需测量精度和计算量的要求。在实验室测试中已经获得了非常有希望的结果，并且本建议针对进一步的功能开发，例如螺旋扫描和实际演示。 工业部件中的实用残余应力测量： 残余应力是在没有任何外部载荷存在的情况下存在于材料中的锁定应力。这些应力非常重要，因为它们显著影响工业部件的尺寸稳定性和材料强度。如果在制造过程中没有检测和控制，可能会发生大量的材料浪费和过早的产品失效。残余应力的“隐藏”特性使得它们难以可靠地测量，需要使用“逆”评估。 残余应力测量通常通过测量当一些受应力的材料被去除时发生的变形来完成，例如，通过钻一个小孔。 光学技术如数字图像相关（DIC）和电子散斑干涉（ESPI）是有吸引力的测量技术，因为它们是非接触的，快速的和经济的。它们提供全场光学数据，允许复杂的解释显着超出了更典型的最小数据测量方法。传统上，DIC和ESPI使用单色光。 拟议的研究旨在利用更大的数据内容提供多色光学测量。这允许从名义上的2-D数据进行3-D变形识别，并能够对残余应力进行更复杂的评估，包括一些目前测量技术无法获得的平面外应力分量。