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Manufacturing with Light Phase 2: Photoelasticity for sub-surface stress measurements in structural ceramics coating systems

光阶段 2 制造：结构陶瓷涂层系统中亚表面应力测量的光弹性

基本信息

批准号：
EP/N018249/1
负责人：
Andrew Moore
金额：
$ 55.53万
依托单位：
Heriot-Watt University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FN018249%2F1
关键词：
Manufacturing Light Phase Photoelasticity sub

项目摘要

Birefringence is a difference in refractive index that occurs along different axes in a material. In some materials this effect is intrinsic due to the atomic structure. In other materials, artificial birefringence can be induced by a mechanical stress that produces anisotropies in the material. Polarized waves travel at different velocities through the stressed regions depending on their polarization direction. This phenomenon is exploited in the well-established technique of photoelasticity, in which a model of the component of interest is made in an optically transparent plastic material and placed between polarizing optics. The induced birefringence is directly proportional to the stress experienced at a given point: contours of constant difference in the principal stresses and contours of the principal stress direction appear as fringe patterns. The technique has played a fundamental role in experimental mechanics, design and manufacturing.This project is concerned with measuring the stress-induced birefringence in materials that are opaque at visible wavelengths. We will use THz illumination up to 7.5 THz where some fraction is transmitted through a range of non-polar materials including ceramics, plastics and composites. Measuring the stress-induced birefringence will provide information on the internal stress distribution in real components that are opaque at visible wavelengths, removing the need to model it in transparent plastic as in photoelasticity. Measurement from the real components also enables direct validation of numerical models. These new techniques will enable in-process control during manufacturing applications and in-service quality assurance, for a range of materials where this is not currently available, enabling step changes in the manufacturing processes used and the components that can be produced.

双折射是指在材料中沿不同轴方向发生的折射率差异。在某些材料中，由于原子结构，这种效应是固有的。在其他材料中，人工双折射可以由产生材料各向异性的机械应力引起。极化波以不同的速度通过应力区，这取决于它们的极化方向。这种现象在成熟的光弹性技术中得到了利用，在这种技术中，感兴趣的组件的模型被制作在光学透明的塑料材料中，并放置在偏振光学器件之间。诱导双折射与在某一点所受的应力成正比：主应力和主应力方向的等高线呈条纹状。该技术在实验力学、设计和制造中发挥了基础性作用。这个项目是关于测量在可见光波段不透明的材料的应力诱导双折射。我们将使用高达7.5太赫兹的太赫兹照明，其中一些部分通过一系列非极性材料（包括陶瓷，塑料和复合材料）传输。测量应力诱导的双折射将提供在可见光波段不透明的真实组件内部应力分布的信息，从而消除了在透明塑料和光弹性中建立模型的需要。来自真实组件的测量也可以直接验证数值模型。这些新技术将使制造应用过程中的过程控制和服务质量保证成为可能，对于目前无法获得的一系列材料，使所使用的制造工艺和可生产的组件能够进行步骤更改。