虚位移场法是一种基于全场变形信息表征材料力学参数的新方法，其具有单次实验可实现多参数测量、测量效率高、实验成本低等优点。研究表明，准确的试件变形场是虚位移场法应用的关键，但目前的网格法和数字图像相关法均难以满足上述需求，迫切需要引入高精度的全场变形测量技术。云纹法测试灵敏度高，测试区域大，具有为虚位移场法提供准确变形场的巨大潜力。但在云纹法测试中，高频云纹栅的制备已成为限制其发展的技术瓶颈。本项目将研究基于云纹法的虚位移场法表征方法和测试技术（云纹虚场法），拟解决虚位移场法表征中高精度变形数据获取的难题；发展基于软压印的新型云纹栅制备和评价技术，突破云纹栅制备的技术瓶颈。研究云纹虚场法测量理论，发展虚位移场优化设计方法，抑制实验误差对参数反演的干扰，研究云纹虚场法的最优试件类型和加载方案，编制云纹虚场法数据处理软件，并应用于高温定向凝固合金及其焊接区域的常温/高温力学参数表征中。

Virtual Fields Method (VFM) is a novel characterization method of constitutive parameters based on the full-field deformation information, possessing the advantages of multi-parameters measurement, high efficiency and low cost. The available results demonstrate that the acquisition of accurate deformation field is crucial for the successful utilization of VFM, but the common used grid method and digital image correlation are difficult to satisfy the requirement, and thus an accurate full-field deformation measurement method is in urgent requirement. Moiré method, owing to its superiorities of high sensitivity and large testing area, has a great potential to offer the desired deformation information for VFM. However, the moiré grating becomes a technical bottleneck which limits the development and application of moiré method, because of the complicated fabrication process and expensive cost. Focusing on the above mentioned challenges, this project is going to establish the moiré-VFM by combine the moiré method with VFM creatively, and solving the difficulty on moiré grating through developing new grating fabrication techniques based on the soft lithography. Furthermore, in this project, we will study the principle of moiré-VFM and relative measurement techniques, establish the design and optimization technique for virtual fields, minimize the disturbance of test error on the reversed constitutive parameters, determine the optimal specimen type and loading mode, develop the process software for moiré-VFM measurement, and apply the moiré-VFM to the room/high temperature constitutive parameters characterization of the directionally-solidified superalloy and its welding zone.