Papers by Keyword: Welded Structures

Abstract: The structural integrity and safety of the vessels depends significantly on the quality of their welded joints, particularly at specific nodes where high-stress concentrations are common. This research leverages computer-aided design, artificial intelligence and materials science advancements to develop an innovative software tool that integrates expert knowledge, and best practices, for inland vessel welding. The proposed expert software system offers several key features, including the visualization of specific ship nodes, their parameters, as well as the residual stresses and strains that are specific to each node. By integrating these functionalities, the software aims to minimize human error, reduce inspection time, and ultimately improve the overall structural reliability of inland vessels.

Abstract: The application of mechanical vibration has been known for many years, but some controversy still exists. According to some ideas the mechanical vibration reduces the technological stresses by summation of technological stress and stress from external loads (vibration). But on the other hand, the mechanical vibration causes more complicated phenomena (micro-relaxation) resulting in dimensional stability close to natural seasoning effects. In the present study authors present results of research into mechanical vibration from the experimental and practical point of view, proving that this process can be used to obtain dimensional stability. The results has also indicated that the reduction of the technological stresses is highly questionable.

Abstract: The paper presents background information and experimental results regarding the assessment of fatigue damage in welded steel structures by thermographic investigations of thermomechanical coupling effects. The results confirm the high potential of specialized thermographic methods for the experimental characterization of all stages of fatigue damage in welded and un-welded components. The technique provides a new experimental mean to investigate early inhomogeneous fatigue damage as mesoplasticity and cracks in the weld toe. The method has been successfully applied during fatigue testing of welded components and allows detecting localized damage as early as 10% to 20% of the total fatigue lifetime of the tested specimens.

Abstract: We surveyed literature and proposed a procedure to identify the fatigue properties from the Brinell hardness and Young’s modulus. And we developed a parameter similar to the S.W.T. parameter with the Brinell hardness and Young’s modulus. Using the parameter and finite element analyses, we evaluated fatigue lives of four kinds of welded joints. The predicted results are in a good agreement with experimental results.

Abstract: Large welded structures, including ships and offshore structures, are normally in operation under cyclic fatigue loadings. These structures include many geometric as well as material discontinuities due to weld joints, and the fatigue strength at these hot spots is very important for the structural performance. In the past, various Non-Destructive Evaluation (NDE) techniques have been developed to detect fatigue cracks and to estimate their location and size. However, an important limitation of most of the existing NDE methods is that they are off-line; the normal operation of the structure has to be interrupted and the device often has to be disassembled. In this study, a new impedance-based structural health monitoring system employing piezoceramic transducers is developed with a special interest in applying the technique for welded structural members in ship and offshore structures. In particular, the impedance-based structural health monitoring technique that employs the coupling effect of piezoceramic (PZT) materials and structures is investigated.