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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.

折射率差是在材料中沿沿着不同轴出现的折射率差。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，人工双折射可以由在材料中产生各向异性的机械应力引起。偏振波根据其偏振方向以不同的速度通过应力区域。这种现象在光弹性的成熟技术中得到了利用，其中感兴趣的组件的模型由光学透明的塑料材料制成，并放置在偏振光学器件之间。诱导双折射与在给定点处经历的应力成正比：主应力的恒定差的轮廓和主应力方向的轮廓呈现为条纹图案。该技术在实验力学、设计和制造中发挥了重要作用。本项目涉及测量在可见光波长下不透明的材料中的应力诱导双折射。我们将使用高达7.5 THz的THz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。测量应力引起的双折射将提供关于在可见光波长下不透明的真实的组件中的内部应力分布的信息，从而消除了在光弹性中在透明塑料中对其进行建模的需要。从真实的部件的测量还能够直接验证数值模型。这些新技术将能够在制造应用过程中进行过程控制，并为目前不可用的一系列材料提供服务质量保证，从而能够在所使用的制造工艺和可以生产的组件中进行步骤更改。