DHI is engaged in development of an industrial GT. GT combustors are assigned a repair and replacement schedule based on the number of starts or number of running hours, therefore it is important to analyze the combustor to ensure that it will meet this requirement. The cyclic starting and stopping of the GT leads to LCF which causes cracks to form in components.
In this paper, the evaluation of structural stability of GT combustor under transient condition is presented. First several load conditions representing the start-up and shutdown of the GT are analyzed to obtain the stresses at various conditions. These transient stresses are reduced in to several closed stress cycles using the Rainflow counting procedure. The Strain range is then calculated using the Ramburg-Osgood method and the LCF calculates the cycle life for each strain range. Finally, all of the results are combined in to one cyclic fatigue life using a cumulative damage rule.