الفهرس 
Introduction and Aim of The WorkOnly 14 pages are availabe for public view
 |  | from | 62 |  |  |
| | | from | 62 | | |
Abstract
High-strength steel is widely used in shipbuilding industries. It is extremely fatigue sensitive due to cutting and welding activities in shipyards. Implementing the cutting process followed by grinding and sandblasting could reduce the effect of surface roughness on fatigue strength. Also, Welded joints represent the major components where the crack begins from the weld toe because of the sudden change in geometry that affects the fatigue life of the structure. Recent developments in numerical modeling methods and automated assessment tools have led to the application of new lightweight structures with improved fatigue design. An investigation of the application of the structural hot spot stress method in the fatigue life assessment of the connection details between the main deck and bulkhead of a navy ship. the fatigue strength of a structural detail will be analyzed by considering the overall structural response from a global model and integrating the global behaviour through a sub-modelling technique into the local model. Parametric modeling is implemented in ANSYS. The fatigue strength could be improved by performing some automated adjustments to the model. On the other hand, normal stress is slightly influenced by the new scantlings which are modified for decreasing the weight of the structure. The fatigue loading is considered in the axial direction due to the hogging action of the waves. After creating a coarse model and getting the critical areas, the sub-model is used for refining the mesh. Optimization by MATLAB software is conducted to obtain optimum mass with infinite endurance structural detail. It is noted that the weight reduction is about 400 kg. The fatigue life and the fatigue strength for the structure are increased.