A mechanism-based random field projection for stochastic analysis of concrete structures and other quasibrittle structures

This study investigates the mathematical algorithm for mapping the continuous random fields of material properties onto the FE meshes, and its implications for the mesh sensitivity in stochastic FE analysis of quasibrittle fracture.We adopt a continuum damage constitutive model, and develop a mechanistic mapping method.The projection of the random fields of material properties onto the FE mesh is governed by the prevailing damage pattern of the finite element.The model is applied to stochastic FE analysis of notched and unnotched flexural specimens under different loading configurations.The numerical analysis also considers different correlation lengths of the random fields of material properties.The simulation shows that, even with the proper energy regularization scheme, the commonly used local mapping and local average methods could yield considerable mesh dependence of the peak load statistics.By relating the mapping algorithm to the underlying damage pattern, the present model is able to mitigate the mesh sensitivity for different specimen geometries, loading configurations, and correlation lengths.