Issue 62

S.Bouhiyadi et alii, Frattura ed Integrità Strutturale, 62 (2022) 634-659; DOI: 10.3221/IGF-ESIS.62.44

Figure 11: A comparison between the result of the simulation and the experimental compression test.

P LASTIC AND RUPTURE DAMAGE PROPERTIES OF COMPRESSED EARTH BLOCKS

T

he plasticity model of a damaged block on ABAQUS, uses the concepts of isotropic damaged elasticity in combination with isotropic plasticity in tension and compression, to represent the inelastic behavior of the block. The two main rupture mechanisms are assumed to be:  Tensile cracking;  Compressive crushing of the material. The plastic damage model on ABAQUS is based on the models proposed by Lubliner et al (1989) and Lee and Fenves (1998) [18]. The model is described in the rest of this section. An overview of the main ingredients of the model is given first, followed by a more detailed discussion of the different aspects of the constitutive model. Strain rate decomposition Additive strain rate decomposition is assumed for the velocity independent model [14]:

     * * * ( ) el pl

(6)

with:  *

: the total strain rate;

  el  *pl

: the deformation rate of the elastic phase; : the strain rate of the plastic phase.

Stress-strain relationship The stress-strain relationship is governed by the damaged scalar elasticity [14,18]:

el

  ) pl

el

pl



 

 

  

0 (1 ) : ( d D

D

: (

)

(7)

where

0 el D el D

: is the initial (undamaged) elastic stiffness of the material;

: is the degraded elastic stiffness. In Fig. 12, the elastic phase is linear up to the value of the initial yield which corresponds to 40% of the ultimate compressive stress   cm u f . According to Hashim et al [17], the 40% ratio is essential to define Young's modulus, which

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