engleski

Validation of the developed triaxial nonlinear material model for concrete

This paper presents validation of newly developed material model for concrete. The model is based on combination of elasto-fracture-plastic formulation, considering all dominant influences in concrete: yielding in compression, fracture in tension, softening and hardening. The modified Mohr-Coulomb criterion for dominant compression stresses, the modified Rankine criterion for dominant tension stresses, exponential softening and function for hardening are considered in this model. All constitutive equations are defined by elementary material parameters (Young’s modulus of elasticity, Poisson’s coefficient, maximal uniaxial tensile and compression stresses, coefficient of tensile correction, maximal tensile and maximal compression strains). A multi-surface presentation of the model is implemented which permits the rapid convergence of the mathematical procedure. Model uses return-mapping algorithm for the integration of the constitutive equations with associated and non-associated flow rules. Considering triaxial stress state, paper presents the structural validation of developed numerical model, which is incorporated into computer programme PRECON3D, on four examples, both experimental and numerical, taken from the literature: (i) four point bending of normal- strength and high-strength reinforced concrete beams with four different constant-zone lengths and two different reinforcement ratios ; (ii) three point bending of reinforced concrete beam ; (iii) prestressed concrete beam ; (iv) prestressed Π-beam.

material model ; nonlinearity ; triaxial stress state ; concrete ; numerical analysis ; validation

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