Knowledge of the mechanical properties of materials is required for the design and analysis of engineering products, however, the characterisation of heterogeneous properties using traditional techniques is limited by spatial resolution or insufficient reliability. This paper presents a novel methodology for the characterisation of heterogeneous mechanical properties by extending the virtual fields method through the automated spatial parameterisation of constitutive parameters. Collaboration with the United Kingdom Atomic Energy Authority provided this project with an application focus on the characterisation of the spatially-varying, elastoplastic mechanical properties of welded joints. The developed methodology enables the novel characterisation of welds with assorted geometries, varied loading configurations and dissimilar materials. Numerical verification of the developed method was performed using synthetic data equivalent to that obtained experimentally using optical measurements, where the kinematic fields are known and controlled. The results confirm that the proposed approach converges towards the target parameter maps without any a priori information on the distribution of the properties, successfully demonstrating the established methodology as a proof of concept.

翻译：材料力学性能的认知是工程产品设计与分析的必要前提，然而，传统技术对异质性能的表征受限于空间分辨率或可靠性不足。本文提出了一种通过本构参数自动空间参数化扩展虚拟场方法的新颖方法，用于表征异质力学性能。与英国原子能管理局的合作使本项目聚焦于焊接接头空间变化的弹塑性力学性能表征。所开发的方法能够对具有不同几何形状、多样加载配置及异种材料的焊缝进行创新性表征。利用与光学测量实验数据等效的合成数据对开发方法进行了数值验证，其中运动场已知且受控。结果证实，所提方法在无需任何性能分布先验信息的情况下收敛于目标参数图，成功展示了所建立方法作为概念验证的有效性。