Dynamic photoelasticity as an aid to sizing surface crack by frequency analysis

Technical Report · Tue Apr 01 04:00:00 EST 1980

OSTI ID:6826790

Singh, A; Burger, C P; Schmerr, L W; Zachary, L W

A method using Rayleigh or surface waves for sizing surface cracks that have been modeled as machine slots is described. Dynamic photoelasticity was chosen to study the overall wave behavior and the mode conversions of a Rayleigh wave as it interacts with narrow slots cut from the edges of a two-dimensional plate model. This technique gives a full-field visualization of the stresses produced by an elastic wave traveling in a solid. The interaction between a Rayleigh wave and a slot was observed from a sequence of pictures taken with a high-speed Cranz-Schardin camera. The procedures and results are discussed. It was concluded that the ability of dynamic photoelasticity to produce full-field views of elastic stress fields can be used to provide an understanding of the ways in which the subsurface particle motions in Rayleigh waves are affected by a slot. As a consequence the Rayleigh wave property which relates the wavelength to its depth below the surface has been effectively used to find the depth of slots. The next step is to use conventional R-wave ultrasonic transducers on artificially machined slots or fatigue cracks to see how the slot depth relates to the cut-off wavelength. The transducers used should be broadband and the depth of the input R-wave should be greater than the slot depth so as to produce undercutting.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6826790
• Report Number(s): IS-M-288; CONF-8009135-1
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420500* -- Engineering-- Materials Testing
CRACKS
DYNAMIC LOADS
ELASTICITY
MATERIALS TESTING
MEASURING METHODS
MECHANICAL PROPERTIES
PHOTOELASTICITY
PHOTOGRAPHY
RAYLEIGH WAVES
SEISMIC SURFACE WAVES
SEISMIC WAVES
SIZE
SOLIDS
STRESS INTENSITY FACTORS
STRESSES
SURFACES
TENSILE PROPERTIES
TESTING
ULTRAHIGH-SPEED PHOTOGRAPHY