Fatigue Performance of Sandwich Composites [chapter]

B Shafiq, F Just, A Quispitupa
2007 Earthquakes and Acoustic Emission  
This paper delineates the results of fatigue testing performed to characterize, i. tensile fatigue lifetime and ii. flexure fatigue lifetime as a function of the thickness of foam core. Sandwich composites were made of single ply carbon fiber facesheets with urehane foam core. Acoustic emission analysis indicated core damage to be the predominant failure activity while fiber rupture served as a precursor to catastrophic failure. Near crack tip region was observed to have multiple crack
more » ... iple crack initiation sites before the onset of crack growth. Crack path was found to erratic on the facesheets while the crack in the foam primarily followed a planar growth along the interface with the facesheets. Both mode I and II cracking was observed in the core and along the interface between the core and the facesheets. Flexural fatigue life was found to be unlimited below 75% of the ultimate static load. Foam core size effect is found to be significant in the crack growth and lifetime behavior. An AE based stiffness reduction model was developed to quantify the extent of damage and stochastic analysis was performed to account for large scatter in the lifetime data.
doi:10.1201/9780203936115.ch20 fatcat:uqvxriimrbhcrgh3hxed7hwcn4