Goangseup Zi

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  • Zdeň Ek, P Bažant, Jang-Jay H Kim, Isaac M Daniel, Emilie Becq-Giraudon, Goangseup Zi +1 other
  • 1999
The effect of structure size on the nominal strength of unidirectional fiber-polymer composites, failing by propagation of a kink band with fiber microbuckling, is analyzed experimentally and theoretically. Tests of novel geometrically similar carbon–PEEK specimens, with notches slanted so as to lead to a pure kink band (not accompanied by shear or(More)
This paper presents a three-dimensional, extrinsically enriched meshfree method for initiation, branching, growth and coalescence of an arbitrary number of cracks in non-linear solids including large deformations, for statics and dynamics. The novelty of the methodology is that only an extrinsic discontinuous enrichment and no near-tip enrichment is(More)
The main characteristics of the cohesive (or fictitious) crack model, which is now generally accepted as the best simple fracture model for concrete, are (aside from tensile strength) the fracture energies G F and G f corresponding to the areas under the complete softening stress-separation curve and under the initial tangent of this curve. Although these(More)
SUMMARY The paper deals with constitutive modelling of contiguous rock located between rock joints. A fully explicit kinematically constrained microplane-type constitutive model for hardening and softening non-linear triaxial behaviour of isotropic porous rock is developed. The microplane framework, in which the constitutive relation is expressed in terms(More)
  • Zden E Ek, P Ba Z Zant, Yong Zhou, Goangseup Zi, Isaac M Daniel
  • 2003
The effect of structure size on the nominal strength of closed-cell PVC foam (Divinycell H100) is investigated experimentally , theoretically and numerically. Two types of size effect are considered––Type I, characterizing failure of structures with large cracks or notches, and Type II, characterizing failure at crack initiation. Geometrically similar(More)
The previously developed eigenvalue method for computing the size effect of cohesive crack model is extended to the cohesive crack model with a finite residual stress. In this model, the structure size for which a specified relative length of kink-band corresponds to the maximum load is obtained as an eigenvalue of a homogeneous Fredholm integral equation.(More)
[1] A size effect law for fracture triggering in dry snow slabs of high enough length-to-thickness ratio is formulated, based on simplified one-dimensional analysis by equivalent linear elastic fracture mechanics. Viscoelastic effects during fracture are neglected. The derived law, which is analogous to Bažant's energetic size effect law developed for(More)
Based on a mathematical model developed in the preceding Part I of this study, a numerical analysis of the process of decontamination of radionuclides from concrete by microwave heating is conducted. The aim is to determine the required microwave power and predict whether and when the contaminated surface layer of concrete spalls off. As customary, the(More)
The paper analyzes a proposed scheme of decontamination of radionuclides from concrete structures, in which rapid microwave heating is used to spall off a thin contaminated surface layer. The analysis is split in two parts: ͑1͒ the hygrothermal part of the problem, which consists in calculating the evolution of the temperature and pore pressure fields, and(More)
Efficient numerical finite-element analysis of creeping concrete structures requires the use of Kelvin or Maxwell chain models, which are most conveniently identified from a continuous retardation or relaxation spectrum, the spectrum in turn being determined from the given compliance or relaxation function. The method of doing that within the context of(More)