Guided plate waves and reflection factor for NDE (Non-Destructive Evaluation) of composite materials

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:6739515

Balasubramaniam, K

An oblique incidence reflection factor analysis and a guided plate wave approach are being adopted in an attempt to explore the potential of utilizing the abundance of ultrasonic wave modes and particle displacement types for the characterization of the material state in fiber reinforced composite structures. The generation and the propagation of guided plate waves in fiber reinforced composites are demonstrated to qualitatively and quantitatively evaluate material degradation problems such as delamination, porosity, fiber volume fraction changes, hydrothermal degradation and fiber mis-orientation. Several anomaly modeling techniques are coupled in order to describe material degradation in multi-layered composites. The global anomalies in the fiber reinforced laminates are modeled as changes in the effective elastic constants and density. The laminated plate theory is then used to smear the elastic properties over the whole composite structure thus enabling the modeling of different ply lay-ups. A new generalized model for plate wave dispersion in composite plates is introduced to establish the relationships between the material state and wave mode generation. The sensitivity of plate wave modes and several of its features capable of characterizing material state is demonstrated, using both experimental and theoretical evidence. The critical angles and resonant frequencies, which are also related to the existence of plate wave modes also reveal the possibility of using oblique incidence reflection factor analysis in the Non-destructive Evaluation (NDE) field. Another useful derivative from this research is the scientific proof for an increased sensitivity of the oblique incidence longitudinal and the oblique incidence shear waves mode to global anomalies such as porosity in fiber reinforced composite materials, a practical NDE tool.

• Research Organization: Drexel Univ., Philadelphia, PA (USA)
• OSTI ID: 6739515
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
MICROSTRUCTURE
ULTRASONIC TESTING
DENSITY
ELASTICITY
FIBERS
LAYERS
MATHEMATICAL MODELS
MEASURING METHODS
NONDESTRUCTIVE TESTING
ORIENTATION
POROSITY
REINFORCED MATERIALS
THERMAL DEGRADATION
WAVE PROPAGATION
ACOUSTIC TESTING
CRYSTAL STRUCTURE
MATERIALS
MATERIALS TESTING
MECHANICAL PROPERTIES
PHYSICAL PROPERTIES
TENSILE PROPERTIES
TESTING
360603* - Materials- Properties