Towards a physical damage variable for a heterogeneous quasi-brittle material
Publication Name: Proceedings of the 11th International Conference on Fracture
Publication URL: https://www.researchgate.net/profile/Eric-Landis/publication/238691283_TOWARDS_A_PHYSICAL_DAMAGE_VARIABLE_FOR_A_HETEROGENEOUS_QUASI-BRITTLE_MATERIAL/links/557736ba08aeacff2000487d/TOWARDS-A-PHYSICAL-DAMAGE-VARIABLE-FOR-A-HETEROGENEOUS-QUASI-BRITTLE-MATERIAL.pdf
Damage mechanics models have been applied to a variety of materials for many years because of the elegant way the models handle progressive degradation and failure. Damage models can be developed with a varying degree of sophistication, can provide insight into different types of material behavior, and can be tailored to a
wide range of applications. A weakness of traditional damage models is the phenomenological nature of the damage variables. Damage variables must be established from laboratory measurements, which can become expensive depending on the model sophistication. The focus of this work is a first step towards defining damage in terms of physical microstructural changes. Small concrete specimens were subjected to cyclic compressive loading while simultaneously being scanned by a synchrotron-based tomography system. The tomography system allowed us to examine internal structural changes at high spatial resolution. Damageinduced changes in specimen stiffness were evaluated using recorded load-deformation response, while internal damage was measured using an array of 3D image processing techniques. Preliminary measurements suggest a power law relationship between the damage variable and measured microcrack surface area.