Abstract
An experimental investigation of the central normal impact and penetration of plates of Columbia Resin No. 39, simply supported at the corners, was conducted using both photoelastic and strain-gage techniques. Both conically-pointed and blunt-nosed steel projectiles of 1/4-in. diam were employed at initial velocities ranging from 191 to 272 fps. Sequences of fringe photographs were obtained by repeating shots on different plates, using various predetermined time intervals between impact and photograph. A dynamic value of Young's modulus has been calculated from the velocity of propagation of tension waves, and a strain-optic coefficient of 398 microinches per fringe for the material was determined from a quasi-static test. Both fringe order and strain histories for various impact conditions have been ascertained and are compared.
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Abbreviations
- c plate :
-
limiting velocity of expansion waves in plates
- E :
-
Young's modulus
- μ:
-
Poisson's ratio
- ρ:
-
mass density
- λ:
-
wave length of fundamental component of loading pulse
- τ:
-
period of fundamental component of loading pulse
- ∈θ :
-
circumferential normal strain
- ∈ r :
-
radial normal strain
- σ θ :
-
circumferential normal stress
- σ r :
-
radial normal stress
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Goldsmith, W., Dabaghian, L. Photoelastic and strain-gage investigation of penetration of thin plates. Experimental Mechanics 1, 121–128 (1961). https://doi.org/10.1007/BF02322900
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DOI: https://doi.org/10.1007/BF02322900