Full-field elasto-plasticity in dissimilar welded joins

由于性能的不确定性，焊接性能的设计规范过于保守。重要的是，标准测试不适用于复杂的应力状态和高度可变的连接几何形状，例如T型连接。这是一个空间复杂的问题，适合于空间分辨全场测量变形。然而，我们迫切需要数值方法来解释有用的参数提取，通知组件设计的实验数据。该项目的目的是开发综合实验建模方法与数字图像相关（DIC）和虚拟领域的方法（VFM）提取全场变形行为的融合相关的不同连接。这将通过现有的数值方法的发展来实现，以提取弹塑性本构参数和真实的应力应变数据，从不同的不同连接几何形状与控制应力集中，以反映托卡马克工程相关的situations.This博士项目将推动VFM参数化对变形区域内不同的焊接接头的自动检测。与有限元分析相比，VFM的速度快125倍，因为它不需要正向建模，迭代求解非线性问题的弱形式平衡方程。

Design codes for weld properties are over-conservative due to uncertainty in performance. Importantly, standard tests are not suitable for the complex stress states involved and the highly variable geometry of joins, e.g. T-joins. This is a spatially complex problem that lends itself to spatially-resolved full-field measurements of deformation. However, we urgently require numerical methods to interpret the experimental data for useful parameter extraction to inform component design. The purpose of this project is to develop integrated experimental-modelling methods with Digital Image Correlation (DIC) and the Virtual Fields Method (VFM) for extracting the full field deformation behaviour of fusion-relevant dissimilar joins. This will be achieved through the development of existing numerical methods to extract elasto-plastic constitutive parameters and true stress-strain data from varied dissimilar join geometry with controlled stress concentrators to reflect tokomak engineering-relevant situations.This PhD project will push VFM parameterisation towards the automatic detection of deformation zones within dissimilar welded joins. In comparison to finite element analyses, the VFM is up to 125 times faster as it requires no forward modelling, iteratively solving the weak form of the equilibrium equations for non-linear problems.