Measurements of damping for nondestructively assessing the integrity of fiber reinforced composites
Development of an experimental method to measure material damping and the assessment of the utility of damping measurements as a tool for quantitatively assessing the integrity of fiber reinforced composites was undertaken. An impulse technique using a non contact probe displacement motion transducer was developed for the measurement of material damping up to the third mode of vibration. The test specimens, fixed-free beams vibrating transversely, were fabricated from five types of composite materials. They were graphite/epoxy, Kevlar/epoxy, and glass/epoxy continuous fiber composites, chopped glass fiber composite, and hybrid composite. The severity of damage simulated by milling-machine cuts correlates well with increased damping. There were no significant changes in damping of the specimens having mylar inserts to represent delaminations. This is attributed to three factors; (1) the inserts being bonded with the material; (2) material damping variation between the specimens being more than the damping change due to inserts; and (3) the variation in damping due to clamping at the mounting base being more than the damping change caused by the mylar inserts.
- Research Organization:
- Florida Univ., Gainesville (USA)
- OSTI ID:
- 6809552
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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