Fatigue Crack Growth and Retardation Using Polycarbonate.
Abstract
This experimental study investigates the 'retardation' effects observed when tensile overloads are applied during fatigue tests of polycarbonate, a transparent polymer. Fatigue cracks are grown in 4-point bend polycarbonate specimens at constant stress intensity ranges in order to obtain constant fatigue crack growth rates. Peak overloads are then applied to the specimens in order to investigate their effects on subsequent crack growth. Simple optical methods are used to observe and photograph the crack tip front at the center of the specimen. Tensile overloads are shown to retard fatigue crack growth in polycarbonate in a manner similar to that observed in metals. Crack tip blunting and crack closure appear to be associated with the retardation mechanism; however, their exact relationship is not investigated. It is concluded that polycarbonate offers potential as a model material for further retardation studies. (Author-PL)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1973
- Accession Number
- AD0769926
Entities
People
- Daniel H. Banasiak
Organizations
- Air Force Institute of Technology