Section 6.13 - Damage Models for Concrete

Abstract

This chapter discusses damage models for concretes. It explains three types of models: isotropic damage model, nonlocal damage, and anisotropic damage model. The constitutive relation is valid for standard concrete with a compression strength of 30-40 MPa. Its aim is to capture the response of the material subjected to loading paths in which extension of the material exists. It should not be employed (1) when the material is confined because the damage loading function relies on extension of the material only, (2) when the loading path is severely nonradial, and (3) when the material is subjected to alternated loading. Further, the model provides a mathematically consistent prediction of the response of structures up to the inception of failure due to strain localization. After this point is reached, the nonlocal enhancement of the model is required. The purpose of nonlocal damage is to describe the nonlocal enhancement of the isotropic damage model. This modification of the model is necessary in order to achieve consistent computations in the presence of strain localization due to the softening response of the material. Further, anisotropic damage model describes a constitutive relation based on elastoplastic damage. This anisotropic damage model is compared to experimental data in tension, compression, compression-shear, and nonradial tension shear.