The effects of a corrosive environment on crack growth rate in chainsteel / A. Amirat (1987)

Public ISBD Titre : The effects of a corrosive environment on crack growth rate in chainsteel Type de document : texte imprimé Auteurs : A. Amirat, Auteur ; W.J. Plumbridge, Directeur de thèse Editeur : Bristol : [s.n.] Année de publication : 1987 Importance : 111 f. Présentation : ill. Format : 30 cm. Note générale : Master of science : Environment : University of Bristol : 1987 Bibliogr. f. 47 - 50 Langues : Anglais (eng) Mots-clés : Corrosive Environment Chainsteel Index. décimale : Ms00787 Résumé : The work presented in this thesis, is a study of the effects of a corrosive environment (3.5% NaC1 solution) on crack growth in tempered chainsteel. Crack growth rates have been investigated in single-edge notched specimens. For growth rates above 10-⁵mm/cycle fatigue crack growth is independent of tempering temperature. A drop of frequency from 78 Hz to 0.6 Hz causes an increase of fatigue crack growth in air by a factor of two. At the lower frequency, in the corrosive environment fatigue crack growth is faster than that in air. These effects are attributed to the fatigue crack tip - environment interaction. Apart from the general observation that Kiscc decreases as the yield strength increases, a significant difference in Kiscc is observed for the 500 °C temper condition according to the specimen location in the heat treated bar. This effect is associated with the hardness difference (10 to 15 Hv30) existing between the outer and inner specimens. Residual stresses in the parent bar after tempering have been found to be compressive at the surface and tensile within the core. However, manufacture of the thin testpiece eliminated most of the residual stresses. The effects of a corrosive environment on crack growth rate in chainsteel [texte imprimé] / A. Amirat, Auteur ; W.J. Plumbridge, Directeur de thèse . - Bristol : [s.n.], 1987 . - 111 f. : ill. ; 30 cm. Master of science : Environment : University of Bristol : 1987 Bibliogr. f. 47 - 50 Langues : Anglais (eng) Mots-clés : Corrosive Environment Chainsteel Index. décimale : Ms00787 Résumé : The work presented in this thesis, is a study of the effects of a corrosive environment (3.5% NaC1 solution) on crack growth in tempered chainsteel. Crack growth rates have been investigated in single-edge notched specimens. For growth rates above 10-⁵mm/cycle fatigue crack growth is independent of tempering temperature. A drop of frequency from 78 Hz to 0.6 Hz causes an increase of fatigue crack growth in air by a factor of two. At the lower frequency, in the corrosive environment fatigue crack growth is faster than that in air. These effects are attributed to the fatigue crack tip - environment interaction. Apart from the general observation that Kiscc decreases as the yield strength increases, a significant difference in Kiscc is observed for the 500 °C temper condition according to the specimen location in the heat treated bar. This effect is associated with the hardness difference (10 to 15 Hv30) existing between the outer and inner specimens. Residual stresses in the parent bar after tempering have been found to be compressive at the surface and tensile within the core. However, manufacture of the thin testpiece eliminated most of the residual stresses.

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Code-barres	Cote	Support	Localisation	Section	Disponibilité	Spécialité	Etat_Exemplaire
Ms00787	Ms00787	Papier	Bibliothèque centrale	Mémoire de Master	Disponible

The microcomputer and the engraving / Mohamed Sahari (1985)

Public ISBD Titre : The microcomputer and the engraving : profile milling machine Type de document : texte imprimé Auteurs : Mohamed Sahari, Auteur Editeur : Bristol : [s.n.] Année de publication : 1985 Importance : 260 f. Présentation : ill. Format : 29 cm. Note générale : PhD Thesis : Electrical engineering : University of Bristol : 1985 Bibliogr. f. 235 - 237 Langues : Anglais (eng) Mots-clés : Microcomputer Engraving Milling machine Profile Index. décimale : D007185 Résumé : The design of a software based control for an engraving/profile milling machine with two-axis contouring and a limited third-axis movement is described. The probleme of encoding and editing character shape on low resolution display devices are identified. Computer graphics techniques are discussed and applied, and a method for character generation for high resolution output devices is developed. A retrofit system for the well known hand-operated pantograph for the production of company seals and nameplates, notices, logos, etc., is described. A novel approach, using an interactive graphics package, for controlling a two-axis contouring machine is presented. A stepper drive system is employed, as it is ideal for digital control. The microcomputer and the engraving : profile milling machine [texte imprimé] / Mohamed Sahari, Auteur . - Bristol : [s.n.], 1985 . - 260 f. : ill. ; 29 cm. PhD Thesis : Electrical engineering : University of Bristol : 1985 Bibliogr. f. 235 - 237 Langues : Anglais (eng) Mots-clés : Microcomputer Engraving Milling machine Profile Index. décimale : D007185 Résumé : The design of a software based control for an engraving/profile milling machine with two-axis contouring and a limited third-axis movement is described. The probleme of encoding and editing character shape on low resolution display devices are identified. Computer graphics techniques are discussed and applied, and a method for character generation for high resolution output devices is developed. A retrofit system for the well known hand-operated pantograph for the production of company seals and nameplates, notices, logos, etc., is described. A novel approach, using an interactive graphics package, for controlling a two-axis contouring machine is presented. A stepper drive system is employed, as it is ideal for digital control.

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Code-barres	Cote	Support	Localisation	Section	Disponibilité	Spécialité	Etat_Exemplaire
D007185	D007185	Papier	Bibliothèque Annexe	Thèse de Doctorat	Disponible	Autre	Consultation sur place