Speaker
Description
Mechanical metamaterials with periodic mesostructures pose severe challenges for full-field measurement techniques when subjected to large deformations. In this contribution, we present a model-driven Digital Volume Correlation (DVC) strategy that tightly couples continuum modeling with experimental analyses of pantographic metamaterials tested within a tomographic chamber.
At the macroscale, pantographic blocks are modeled as second-gradient continua, providing predictions for the displacement of a set of representative material points, chosen as the centers of hinges or pivots in the underlying architecture. These predictions are then used, via static condensation, to construct a mechanically consistent initial guess for a finite-element-based DVC scheme, which is subsequently refined by minimizing gray-level residuals with suitably tuned mechanical regularization.
The approach is applied to in situ three-point bending tests on 3D-printed pantographic blocks with both deformable hinges and perfect pivots, investigated under extreme loading conditions where imposed displacements reach a significant fraction of the specimen size. Non-incremental DVC analyses initialized by the model-driven procedure successfully reconstruct the deformed configurations, and comparisons with incremental DVC using intermediate scans show very close agreement in terms of displacement fields and gray-level residuals.
These results demonstrate that embedding suitable second-gradient models within DVC workflows enables reliable experimental quantification of complex deformation mechanisms in architected metamaterials, while also reducing computational cost and enlarging the range of experimentally accessible loading paths.
Main reference:
Ciallella, A., Murcia Terranova, L., Smaniotto, B., Vintache, A., Hild, F., Model-driven digital volume correlation: A step forward in experimental analyses of metamaterial deformations. Mathematics and Mechanics of Solids, 10812865251386430.