GALCIT Colloquium

Experiment inspires theory, and theory challenges experiment. X-ray tomography, a 3D visualization tool, can become a precision measurement instrument for full-field spatiotemporal mechanical measurements in materials. An exemplary case testifies continuum theories of elastic fracture mechanics through tests on architected solids, revealing unexpected ductile behaviour in discrete brittle systems. This reshapes mechanical metamaterial design, also providing a plausible explanation for rising R-curves in bones. X-ray measurements can go beyond visualization, by developing methods for 3D strain measurements in nominally homogeneous solids (Flux Enhanced Tomography for Correlations) from rubbers to alloys. The results enrich established constitutive models in rubber elasticity (showing the presence of a mobile phase that violates volume conservation locally). The extensive three-dimensional dataset fuels data-driven mechanics too. Looking forward, the vision is to establish a laboratory for comprehensive X-ray-based full-field measurements, covering all nine components of total strain in 3D, including elastic components (energy dispersive X-ray diffraction)—an ambitious effort, the first of its kind in a laboratory, addressing the challenge of constitutive modelling based on experimental data. This approach can unlock interdisciplinary research realms, from functionally graded alloys to understanding material micromechanics. Applications span from aerospace structures to biomedical devices, promising precision, innovative material design, and exploration of a new area in experimental mechanics.