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Item type:Publication, Access status: with files , Application of welding simulation to block joints in shipbuilding and assessment of welding-induced residual stresses and distortionsDuring ship design, welding-induced distortions are roughly estimated as a function of the size of the component as well as the welding process and residual stresses are assumed to be locally in the range of the yield stress. Existing welding simulation methods are very complex and time-consuming and therefore not applicable to large structures like ships. Simplified methods for the estimation of welding effects were and still are subject of several research projects, but mostly concerning smaller structures. The main goal of this paper is the application of a multi-layer welding simulation to the block joint of a ship structure. When welding block joints, high constraints occur due to the ship structure which are assumed to result in accordingly high residual stresses. Constraints measured during construction were realized in a test plant for small-scale welding specimens in order to investigate their and other effects on the residual stresses. Associated welding simulations were successfully performed with fine-mesh finite element models. Further analyses showed that a courser mesh was also able to reproduce the welding-induced reaction forces and hence the residual stresses after some calibration. Based on the coarse modeling it was possible to perform the welding simulation at a block joint in order to investigate the influence of the resulting residual stresses on the behavior of the real structure, showing quite interesting stress distributions. Finally it is discussed whether smaller and idealized models of definite areas of the block joint can be used to achieve the same results offering possibilities to consider residual stresses in the design process. © SNAK, 2014.Publicationtype: Journal ArticleScopus© Citations 5 229 289 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Eigenspannungs- und Fertigungseinflüsse an Sektionsstößen von Schiffen(2013); Fricke, WolfgangThe dissertation deals with the following influence parameters on the fatigue and fracture strength of block joints: the welding gap width to be filled (8, 15, 30 mm), the welding technique (string-bead and weaving technique), the steel grade (A235, D36), the welding position (PA,PF) and the residual stresses influenced by these factors. The investigations were carried out experimentally and calculational with small scale specimens and in addition numerically by considering the original block joint.Publicationtype: Doctoral Thesis648 380 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Welding of large gaps of block joints in ships using different techniquesWhen welding block joints of ships it may occur that the gaps between them are relatively large. Furthermore high stresses due to the constraint conditions may result in high residual stresses. Therefore an investigation was performed to determine if gap widths up to 30 mm fulfil the requirements regarding the fatigue and fracture strength. The welding of butt joints at 250 mm wide plates was performed under definite constraints presenting the surrounding ship structure. Among other parameters the welding method (string-bead, weaving technique) was varied. During the welding the reaction force was measured and it was noticed that it was remarkably higher for the weaving technique compared to the string-bead technique. Both welding techniques lead to different fracture and fatigue results. The weaving technique seems to be more adequate when welding large gaps. A numerical welding simulation using the weaving technique showed compressive plastic strains in the root layer that maybe reasonable for the good results. Generally the investigations indicated a clear influence of welding technique on the fatigue and fracture strength. The gap width did not have a significant influence. © 2011 Taylor & Francis Group, London.Publicationtype: Conference Paper68 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Erster Interdisziplinärer Workshop Maritime Systeme : aktuelle Ergebnisse aus laufenden Promotionsprojekten an der TUHH(Forschungsschwerpunkt Maritime Systeme der TUHH, 2010-02-09); ; ; ; Es handelt sich um die Sammlung der Beiträge zum ersten Interdisziplinären Workshop Maritime Systeme der TUHH. Folgende Beiträge sind enthalten: - Vereinfachte Bestimmung des effektiven Nachstroms in Manövriersituationen - Numerische Untersuchungen zur Grundberührung von Schiffen Betriebsgrenzen von Ladeoperationen im Seegang - Innovative lasergestützte Schweißfertigung im Schiffbau - Festigkeit von mit großem Luftspalt verschweißten Stößen von Schiffssektionen - Mehrskalenberechnungen mit Anwendungen auf zelluläre Materialien - Corporate Sustainability Management in der Containerschifffahrt - EMV Probleme auf modernen Schiffen - Source Localization and Tracking with a Swarm of Autonomous Underwater VehiclesPublicationtype: Conference Proceedings1032 1082