Fatigue Analysis Of Aluminium Soft Toe Bracket Structures

With the current ship lightweight, quickly, large-scale trend of rapid development,high-speed lightweight ship arises at the historic moment. Due to the performancerequirements of high-speed light ship, many of the structure are made by aluminum alloymaterials. Although aluminum alloy to ensure the structure strength of the ship, but dueto the changes in the trading area, the high-frequency vibrations of the engine made thesoft toe bracket structure in high-speed light ship vulnerable to fatigue failure. Thefatigue properties of aluminum alloy soft toe bracket structures in shipbuilding industryis still relatively small, Separated in this paper the soft toe bracket structures alone, tostudy the fatigue performance, has an important academic significance and theoreticalvalue.First, based on the S-N curve and Palmgren-Miner linear cumulative damage theory,fatigue properties of the soft toe bracket structures were analyzed. Explored size changeon the fatigue performance of the soft toe bracket structures, put forward a moreoptimized improved model.Secondly, based on the virtual crack closure technique, the fatigue performance ofthe existing initial crack soft toe bracket was analyzed. Based on the basic assumptionsof the theory of virtual crack closure technology, used FORTRAN language programmodel into a computable eight-node fatigue unit based on the basic assumptions of thetheory of virtual crack closure technology, check the program. Analysis of the memberthickNess of the soft toe bracket structure fatigue performance impact analyzed to thereducing-hole size and soft toe size of structural fatigue performance of the soft toebracket. Several different soft toe bracket structures were proposed, and a comparativeanalysis of its fatigue properties.Finally, the results show that:(1) the eight nodes fatigue development unit can accurately analyze the fatigue properties of the structure of traditional soft toe bracketstructure is optimized, its fatigue properties have been greatly improved.(2) The fatigueproperties of the panel structure of the soft toe bracket largest show strong regularity ofthe other component parameters on the performance impact of structural fatigue.Generally speaking, of this paper work that analysis to provide ideas for the fatigueperformance of the typical structure of a ship, and also can provide some reference forengineering applications.