SAID T. GOMAA, MOHAMMED H. BALUCH, HAMDY H. ABDEL‐RAHMAN and AMMAR K. MOHAMMED
A finite element formulation for flexure of isotropic plates based on a recent refined theory is developed. The refined theory incorporates effects of transverse shear, transverse…
Abstract
A finite element formulation for flexure of isotropic plates based on a recent refined theory is developed. The refined theory incorporates effects of transverse shear, transverse normal stress and transverse normal strain. The Galerkin finite element method was used to develop the finite element equations for both plate bending and inplane problems. The performance of the proposed finite element model was evaluated by solving problems of uniformly loaded thick plates with different support conditions. The results of the present formulation are compared with Mindlin/Reissner and elasticity solutions.
Details
Keywords
M.S.A. ABBASI, M.H. BALUCH, A.K. AZAD and H.H. ABDEL‐RAHMAN
This paper presents the full range sensitivity study of various components of material model on the response of reinforced concrete slabs subjected to central patch loads using…
Abstract
This paper presents the full range sensitivity study of various components of material model on the response of reinforced concrete slabs subjected to central patch loads using non‐linear finite element analysis. A layered degenerate quadratic plate element with five degrees of freedom was employed. Smeared crack model was used with orthogonal cracking. The components considered in this work are: perfectly plastic models versus hardening models, role of crushing condition on collapse load, influence of dowel effect on punching capacity, parametric variation of tension stiffening parameter, parametric variation of degraded shear modulus and the role of yield criterion.
Details
Keywords
Hamdy H. Abdel‐Rahman, Mohammed H. Baluch and Ali I. Al‐Hejji
A new finite element model has been developed for the analysis of thick beams that incorporates the influence of transverse normal strain in addition to the effect of transverse…
Abstract
A new finite element model has been developed for the analysis of thick beams that incorporates the influence of transverse normal strain in addition to the effect of transverse shear strain. It has been shown that the inclusion of the normal strain effect into Timoshenko beam formulation, in the new model, results in the modification of the element force vector only, where a new term is added, while keeping the flexural and shear contributions to the element stiffness matrix unchanged. Comparisons between closed form solutions, Timoshenko beam results and the results of the new model for isotropic beams of depth to span ratio of up to 0.5, show that the new development reduces the errors with respect to exact solutions to almost a half at a very little extra expense.
A.M. Abdel‐Gaber, H.H. Abdel‐Rahman, A.M. Ahmed and M.H. Fathalla
The aim of this paper is to elucidate the mechanism and the effect of different monohydric organic solvent on the corrosion behaviour of zinc in distilled water.
Abstract
Purpose
The aim of this paper is to elucidate the mechanism and the effect of different monohydric organic solvent on the corrosion behaviour of zinc in distilled water.
Design/methodology/approach
The corrosion behaviour of zinc in stagnant distilled water containing 0‐70 percent (v/v) methanol, ethanol or n‐propanol was investigated at 25‐40°C using potentiodynamic polarization technique. The activation parameters that govern zinc corrosion in mixed solvent system were also calculated.
Findings
The data revealed that, the corrosion of zinc in mixed solvents depends on two factors: the hydrolysis rates of the metal ions in alcohol‐water solutions and the chemisorption of organic solvent molecules at the metal surface. When the latter effect predominant the final result is an increase of the inhibiting effect. On the other hand, when the first factor is dominant the final result is a decrease in the protection efficiency and may exhibit an accelerating effect.
Research limitations/implications
Special attention should be made on using mixed water‐alcohol solvents. Methanol, 50 percent (v/v), has unexpected accelerating effect whereas 70 percent (v/v) exhibits protection efficiency of ≈58 percent.
Originality/value
Owing to environmental concerns, the use of alcohol in automotive fuel increases. Therefore, it is of importance to study the corrosion behaviour of zinc in alcoholic solution.
Abd El-Thalouth I., Rekaby M., Abdel-Rahman A.H. and El-khabery Sh. A.
Galactomannan gum isolated from the seeds of sesbania is subjected to chemical modification via phosphorylation. This is conducted via heating moistened blends of the gum with a…
Abstract
Galactomannan gum isolated from the seeds of sesbania is subjected to chemical modification via phosphorylation. This is conducted via heating moistened blends of the gum with a mixture of orthophosphate salt. Three different phosphate ester derivatives are prepared by changing the reaction time. The %P increases from 0.07 to 0.12 to 0.61 by increasing the reaction time from 30 to 60 to 90 minutes.
Modification of sesbania gum via phosphorylation increases the stability of their pastes to storing. Investigation of the rhelogical properties of these pastes indicate that they are characterised by non-Newtonian pseudoplastic behaviour. As the extent of the reaction increases, i.e. %P, the apparent viscosity of the pastes at a constant rate of shear decreases, while storing does not change the rheological characteristics of the pastes.
Utilization of these derivatives as thickening agents in printing wool fabrics by using acid dyes indicate that phosphate derivatives of sesbania seeds could be used as a thickening agent in printing wool fabrics with acid dyes, where the K/S slightly decreases less than the commercial thickening agent named (Meypro gum) while the overall fastness properties are nearly identical.
Details
Keywords
Jungyul Sohn, Geoffrey J.D. Hewings and Tschangho John Kim