Non‐orthogonal cracks in a smeared finite element model

TLDR

The decomposition enables coupling crack formation with plasticity, creep, thermal effects, shrinkage, and comparison to existing concrete crack models. The study introduces a new model for non‑orthogonal cracks within the smeared crack concept. The model decomposes total strain into concrete and crack components and is applied to shear‑failure problems in reinforced concrete beams and slabs. Results show that reduced integration is unreliable for crack problems and that numerical divergence does not necessarily indicate structural failure.

Abstract

A new model for handling non‐orthogonal cracks within the smeared crack concept is described. It is based on a decomposition of the total strain increment into a concrete and into a crack strain increment. This decomposition also permits a proper combination of crack formation with other non‐linear phenomena such as plasticity and creep and with thermal effects and shrinkage. Relations are elaborated with some other crack models that are currently used for the analysis of concrete structures. The model is applied to some problems involving shear failures of reinforced concrete structures such as a moderately deep beam and an axisymmetric slab. The latter example is also of interest in that it confirms statements that ‘reduced integration’ is not reliable for problems involving crack formation and in that it supports the assertion that identifying numerical divergence with structural failure may be highly misleading.