Abstract
Surface strains in flat plates subjected to static loads were accurately determined from projection-moiré displacements. The moiré displacements and strains were evaluated by comparison with the dial-gage deflections and strains measured by resistance-type strain gages. The moiré diflections and strains were further evaluated by comparison with the values predicted by three analytical methods—small-deflection beam theory, large-deflection beam theory, and small-deflection plate theory. It was found that strains in flat-plate structures can be determined from projection-moiré displacements to an accuracy better than 10 percent.
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Abbreviations
- A m ,B m :
-
amplitudes of displacement, m
- a, b :
-
length and width of the four-point-bending plate specimen, m
- \(\bar D\) :
-
bending rigidity of plate\( - E\bar I/1 - v^2 ,N - m\)
- E :
-
Young's modulus, Pa
- h :
-
thickness of specimen, m
- I :
-
ray number which can have positive or negative values
- \(\bar I\) :
-
moment of inertia of cross section=bh 3/12, m4
- \(\bar P\) :
-
concentrated point load on the beam, or total line load on the plate, N
- q :
-
intensity of uniformly distributed load, Pa
- X B ,X C :
-
horizontal lengths of regions AB and BC of the beam, m
- Y B ,Y C :
-
vertical displacements of loading point B and the tip of the beam specimen, m
- W :
-
deflections of plate, m
- \(\varepsilon _x ,\varepsilon _y \) :
-
strain components, μm/m
- ν:
-
Poisson's ratio
- j, m :
-
summation subscripts
- x, y :
-
Cartesian-coordinate axes
- ζ:
-
coordinate defining the position of loads, m
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Raju, B.B., West, B.S. & Piekutowski, A.J. Strains in flat plates from moiré-displacement patterns. Experimental Mechanics 24, 93–101 (1984). https://doi.org/10.1007/BF02324990
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DOI: https://doi.org/10.1007/BF02324990