HELP versus HEDE in progressively cold-drawn pearlitic steels: Between Donatello and Michelangelo

Evaluation of the Technical State of Reinforcement of the Concrete-Beam Span of a Bridge Constructed at the End of the Last Century

Loss of Cohesion Between Concrete and Steel Reinforcement Under the Influence of Corrosive-Hydrogenating Media

We analyze the existing algorithms, models, and procedures of evaluation aimed at the investigation of the irreversible processes of land-sliding and deformation of soils and rock masses. We establish the advantages both of the Cundall procedure [based on the cyclic (in time) scheme of evaluation of the incremental strain rates according to Newton's second law of motion and the levels of stresses and strains according to generalized Hooke’s law] and of the Coulomb–Mohr strength model modified by introducing the ultimate tensile strength. The dissipation of the kinetic energy caused by the temporal disbalance of forces is described by the introduction of damping forces proportional to the active forces and strain rates. The novelty of results of our investigations is explained by the combination of the indicated algorithms and models on the basis of the finite-difference scheme of numerical analyses guaranteeing the possibility of reliable calculations of large irreversible deformations of rocks, which makes it possible to reproduce the actual history of their landslides and deformations beyond the level of ultimate strength. The practical significance of performed investigations is confirmed by the comparison of accumulated data with the data of geodesic observations of the landslides of ground slopes.

Modeling of the Irreversible Deformation of Soils and Rock Masses by the Methods of the Theory of Elasticity

Evaluation of the State of Subsurface Layers of the Metal Subjected to Shot Peening with the Help of Surface Acoustic Waves

The changes in the plasticity characteristics of prestressing steel wires in air and in hydrogenating environments caused by the process of cold drawing are investigated on the basis of slow strain-rate tests on smooth specimens. The tested pearlitic steel is highly susceptible to hydrogen embrittlement in all stages of cold drawing. The inconsistency is revealed between the changes of two plasticity characteristics: reduction in area and uniform elongation. The obtained results are analyzed by distinguishing the contributions of resistance to crack initiation and crack propagation. The susceptibility to crack initiation increases as a result of cold drawing with simultaneous improvement of the crack propagation resistance.

Analysis of the Plasticity Characteristics of Progressively Drawn Pearlitic Steel Wires

The susceptibility to hydrogen-assisted cracking of cold-drawn pearlitic steel wires used as reinforcement in concrete is studied in alkaline media modeling pore liquids in concrete The prestressing steel is established to become susceptible to hydrogen embrittlement under potentials of – 11 V (SCE) The maximum fracture load, as well as the elongation to fracture, decrease as the cathodic potential increases; the effect is more noticeable for slow strain rates The fracture mechanism in aggressive media differs from the fracture mechanism in air The role of surface defects in the environment-assisted cracking is discussed

Susceptibility of Prestressing Steel Wires to Hydrogen-Assisted Cracking in Alkaline Media Simulating Concrete Pore Solutions

We study the influence of plastic deformation of St.3 steel on the velocity of Rayleigh surface acoustic waves measured by the method of laser recording. It is shown that plastic strains lead to the formation of anisotropy of the acoustic properties mainly determined, according to the data of evaluation of residual mechanical stresses, by the texture of steel.

М. І. Hredil

Papers

Analysis of the Plasticity Characteristics of Progressively Drawn Pearlitic Steel Wires

Susceptibility of Prestressing Steel Wires to Hydrogen-Assisted Cracking in Alkaline Media Simulating Concrete Pore Solutions

Investigation of the Space Distribution of the Velocity of Surface Acoustic Waves in Plastically Deformed Steel by the Laser Method