On Subsurface Crack Growth in Fibre Metal Laminate Materials
DELFT UNIV OF TECHNOLOGY (NETHERLANDS)DEPT OF AEROSPACE ENGINEERING
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Fatigue crack growth in fibre metal laminates FMLs is significantly more complex than in monolithic materials due to the interaction of various physical mechanisms that govern the growth of cracks in laminates. Extensive research has gone into the development of analytical models that try to predict the growth of surface and through-cracks in the FML Glare under fatigue loading. To date, less emphasis has been placed on developing fatigue crack growth models for part through cracks. These part through cracks exhibit different rates of growth for each layer of the laminate based upon differing stress levels and delamination zone sizes. To better predict the residual strength of FML structures, understanding the behavior of subsurface crack growth is required. For this reason, data of crack growth rates for layers of various laminates were compared to an analytical fatigue crack growth model developed for surface cracks in a specific type of FML, Glare. This paper gives an initial assessment of the models veracity for subsurface crack growth.