Mechanical movement in electronic products and structures

该项目旨在发展非接触式接触式光学形式计量在莱昂纳多的使用。这将主要涉及评估和开发数字图像相关（DIC）的使用，以测量外部形式的运动，以揭示材料的机械性能。本项目将开发将DIC与热室结合使用的校准方法，以计算位移和热膨胀系数。它还将评估是否可以改进这些测量的可靠性和准确性。一旦可接受的测量方法被开发和表征，该项目将接着评估DIC测量在莱昂纳多特别感兴趣的一系列工业研究应用中的有用性和局限性。这将主要是利用DIC技术来揭示无铅焊料的性能及其与层压板pcb的结合使用。这些材料通常是复合结构，人们对其材料性质知之甚少。使用DIC技术获得的信息将用于开发复杂结构的有限元分析模型，以提高对未来结构的理解，并支持公司内部的设计数字化努力。制造商为GOM DIC系统提供的校准仅限于室温。对于高温测量，该设备没有合格的测试方法。因此，需要开发新的系统校准方法。使用DIC测量热膨胀系数是一种非标准的测试方法，其可靠性和通用性作为一种技术尚未得到充分的探索。使用DIC和热室测量CTE的技术的发展，将使一种精确的非接触方法能够了解材料特性，从而在未来改进建模。在热负荷中使用热室提供了更均匀的热量分布，并且与使用加热板的其他研究相比，使用DIC技术可以提供更准确的CTE测量。机械运动的测量，特别是在热负荷下，揭示了复合材料和结构的进一步信息，否则是不可用的。这些信息可用于告知复合材料结构在其使用寿命期间的可靠性和性能。本项目旨在了解DIC在研究的应用领域中可以应用到何种程度，并评估该测量方法在大尺度和小尺度上的局限性。DIC技术提供的信息也可以用来提高有限元模型的建模精度，而不是目前可用的。也有可能发展使用DIC与其他测试方法相结合。这可能包括使用LWIR相机进行直接热成像测量，这将需要在像素和信息级别进行图像配准和传感器数据融合。此外，将GOM形式畸变测量与声发射测试相结合可以提供有关材料特性的进一步信息。这将允许在比较结构时评估DIC的局限性。声发射传感器的增加将有可能在DIC成像传感器显示材料内部变形之前收集数据。结合使用，这些方法可以更好地了解复合材料结构的内应力和外部应变。

The project aims to develop the use of non-contact contact optical form metrology at Leonardo. This will primarily concern assessing and developing the use of digital image correlation (DIC) to measure movement in external form in order to reveal mechanical properties of materials. This project will develop calibration methods for the use of DIC in combination with a thermal chamber to calculate displacement and coefficients of thermal expansion. It will also assess whether any improvements to the reliability and accuracy of these measurements can be made. Once acceptable methods of measurement have been developed and characterised, this project will then move to assess the its usefulness and limitations of DIC measurements across a range of industrial research applications of particular interest to Leonardo. This will primarily be exploiting DIC technology to reveal properties of Lead free solder and its use in combination with laminate PCBs. These materials are often composite structures of which little is known about their material properties. The information revealed using DIC techniques will be used to develop finite element analysis models of the complex structures measured to improve understanding of future structures and support design digitization endeavors within the company.The calibration provided by the manufacturer for the GOM DIC system is limited to room temperature. For high temperature measurements, there is no qualified testing methodology for the device. Therefore new calibration methodology for the system should be developed. Measurement of coefficients of thermal expansion using a DIC is a non-standard test method and its reliability and versatility as a technique has not fully been explored. The development of a technique to measure CTE using DIC in conjunction with a thermal chamber would enable an accurate non-contact method to inform material properties for improved modelling in the future. The use of a thermal chamber in thermal loading provides a more uniform heat distribution and could provide more accurate CTE measurements with the DIC technology than performed in other studies using heater plates.The measurement of mechanical movement, particularly under thermal loads, reveals further information on composite materials and structures that is otherwise unavailable. This information can be used to inform on reliability and performance of composite structures over their lifetime. This project strives to understand to what extent DIC can be used in the application areas studied and to assess the limitations of the measurement method at the large and small scale. The information provided by DIC technology can also be used to improve the modelling accuracy of finite element models than what is currently available. There is also potential to develop the use of DIC in conjunction with other test methods. This may include direct thermal imaging measurements with a LWIR camera that will require image registration and sensor data fusion at the pixel and information levels. Moreover, combining GOM form distortions measurements with acoustic emissions testing may provide further information on material properties. This would allow the assessment of the limitations of DIC when comparing structures. The addition of acoustic emissions sensors would potentially allow data to be collected on internal material distortion before it becomes visible with the DIC imaging sensors. Used in conjunction, these methods could provide greater understanding on internal stress and external strain in composite structures.