Crack depth determination by ultrasonic frequency analysis aided by dynamic photoelasticity

Technical Report · Fri Aug 01 04:00:00 EDT 1980

DOI:https://doi.org/10.2172/5152960· OSTI ID:5152960

Singh, A

A non-destructive method for characterizing the depth of artificial surface-breaking flaws (slots) using Rayleigh surface waves is described. Dynamic photoelasticity was used to obtain a full-field visualization of the waves generated on interaction of a Rayleigh wave with a slot. This visualization showed that for slot lengths of the same order of size as the predominant wavelengths in the incident Rayleigh wave, there is a significant interaction of the subsurface Rayleigh disturbance with the slot tip, producing transmitted surface disturbances that were quantitatively analyzed. Specifically, the frequency content of these transmitted waves was found for four different slot depths. The high frequency components of these transmitted signals exhibited a maximum frequency which decreased with increasing slot depth. This was attributed to the fact that the maximum frequencies of the subsurface field of the incident Rayleigh wave decrease with increasing depth. Ultrasonic testing was also done on surface slots in steel blocks, using commercial Rayleigh wave transducers. A relationship similar to the photoelastic results was obtained for the frequency components of the transmitted waves at the surface relative to the slot depth. However, in the ultrasonic case, there was a definite high frequency cut off point which could be directly related to the slot depth for slots perpendicular to the surface. This relationship was shown to also accurately predict the depth of inclined slots.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5152960
• Report Number(s): IS-T-900
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420500* -- Engineering-- Materials Testing
ACOUSTIC TESTING
CONFIGURATION
CRACKS
DEFECTS
ELASTICITY
ELEMENTS
FRACTURE PROPERTIES
MATERIALS TESTING
MECHANICAL PROPERTIES
METALS
NONDESTRUCTIVE TESTING
PHOTOELASTICITY
RAYLEIGH WAVES
SEISMIC SURFACE WAVES
SEISMIC WAVES
TENSILE PROPERTIES
TESTING
ULTRASONIC TESTING