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In this paper, Isoparametric finite element formulations are derived for special elements for representing the steel‐concrete interface. Curved multi‐noded Isoparametric element for reinforcing steel idealization is proposed. In addition, special thin Isoparametric element in a form of a sheath is suggested in order to model the bond‐slip characteristics. Special provisions are taken into account to avoid numerical difficulties. The proposed elements are incorporated in non‐linear finite element program DMGPLSTS and applied to the problem of tension stiffening of reinforced concrete members. The results are noted to reflect a softer overall response attributable to the slip effect.

The most simple equivalent frame system with reduced degrees of freedom is proposed for handling multi‐story multi‐bay infilled frames. The system is composed of homogenized continuum for the reinforced concrete members braced with unilateral diagonal struts for each bay, which are only activated in compression. Identification of the equivalent system characteristics and nonlinear material properties are accomplished from the concepts of inverse analysis approach along with statistical tests of hypotheses is employed to establish the appropriate filtering scheme and the proper accuracy tolerance. The suggested system allows for nonlinear finite element static and dynamic analysis of sophisticated infilled reinforced concrete frames. Sensitivity analysis is undertaken to check the suitability of the proposed system to manipulate various structural applications.

This article presents the galvanostatic anodic oxidation of two types of stainless steel alloys, ferritic (15.03% Cr) and austenitic (20.45% Cr, 8.37% Ni), in molten NaNO₃‐KNO₃ eutectic mixture at different temperatures ranging from 673‐873K. At a temperature of 673K the shape of polarization curves for the alloys is complex, while at higher temperatures it is simple. The passivity potential range was calculated as the difference between the passivation potential, E_p, and the breakdown potential, E_b. The value of E_b – E_p decreases with the increase of temperature. The amount of iron, chromium and nickel dissolved in the melt was determined after each experiment using atomic absorption spectroscopy. The composition and structure of the corrosion products formed on the surface of electrodes were examined by X‐ray diffraction analysis. Corrosion parameters derived from the polarization curves are calculated; these are: polarization resistance at low current densities, R_p, exchange current density, i_o, corrosion current density, i_corr, passivation current density, i_p. It was found that the increase of temperature increases i_o, i_corr, and i_p while R_p, decreases. From these results it was found that, under the given conditions, the austenitic stainless steel alloy is more corrosion resistant than the ferritic one. The activation energy of corrosion was estimated for the two alloys.