Rheological-dynamical continuum damage model for concrete under uniaxial compression and its experimental verification

Abstract

A new analytical model for the prediction of concrete response under uniaxial compression and its experimental verification is presented in this paper. The proposed approach, referred to as the rheological-dynamical continuum damage model, combines rheological-dynamical analogy and damage mechanics. Within the framework of this approach the key continuum parameters such as the creep coefficient, Poisson?s ratio and damage variable are functionally related. The critical values of the creep coefficient and damage variable under peak stress are used to describe the failure mode of the concrete cylinder. The ultimate strain is determined in the post-peak regime only, using the secant stress-strain relation from damage mechanics. The post-peak branch is used for the energy analysis. Experimental data for five concrete compositions were obtained during the examination presented herein. The principal difference between compressive failure and tensile fracture is that there is a residual stress in the specimens, which is a consequence of uniformly accelerated motion of load during the examination of compressive strength. The critical interpenetration displacements and crushing energy are obtained theoretically based on the concept of global failure analysis. [Projekat Ministarstva nauke Republike Srbije, br. ON 174027: Computational Mechanics in Structural Engineering i br. TR 36017: Utilization of by-products and recycled waste materials in concrete composites for sustainable construction development in Serbia: Investigation and environmental assessment of possible applications]

Rheological-Dynamical Continuum Damage Model Applied to Research of the Rotational Capacity of a Reinforced Concrete Beams

“…Moreover, to identify global failure as a continuum with damage, the damage variable must be formulated first. The proposed stress-strain curve given by the first author in [11] is shown to provide very good predictions for the stress versus strain response in the prepeak regime. Within this global model the three main failure characteristics, the residual stress, the critical value of interpenetration displacement and the crushing energy, are theoretically evaluated.…”

“…The numerically defined dynamic and static RDA curves are presented in Table 2. The acceleration coefficient f γ = 1.37 was used in the computation for all concrete compositions as detailed in [11].…”

“…2 Comparative analysis for five concrete compositions 2.1 Average RDA stress-strain curve The RDA modulus function has been used in [11] to obtain the quasi-static stress-strain curve, as follows…”

“…where ϕ * is the structural creep coefficient and K E is the structural-material constant at the limit of elasticity as detailed in [11]. As detailed by Van Mier et al [1], the stress-strain curves of concrete are dependent on two major groups of parameters: testing conditions and concrete characteristics.…”

“…To identify the basic mechanism that leads to concrete damage growth, some primary features of experimentally observed concrete behavior are presented first, see [11].…”