Experimental Mechanics

, Volume 4, Issue 11, pp 335–344 | Cite as

Plastic strains and energy density in cracked plates

Part I-experimental technique and results To facilitate presentation of data and comparison to available theory, this paper is divided into two parts: the first is primarily concerned with experimental procedure and results; and the second is concerned with correlation of data to elastic theory and a discussion of ductile fracture in light of experimental evidence
  • William W. Gerberich


A technique is presented which allows separation of the principal plastic strains within an enclave at a crack tip in relatively thin plates. For plates with a number of crack lengths, several degrees of tensile loading are applied to five ductile materials with widely varying mechanical properties. Principal plastic strain distributions, plastic distortional strain energy density and total plastic energy are determined within the resulting plastic encalves. It is shown that the degree of loading and strain hardening greatly affect the principal plastic strain and energy density distributions and that this is reflected in the amount of strain energy that can be plastically absorbed at a crack tip.


Energy Density Fluid Dynamics Plastic Strain Density Distribution Crack Length 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



half crack length


incremental area within enclave


principal plastic strains


relative retardation of 2.27×10−5 in. corresponding to first fringe order


tensile modulus of elasticity


loading factor defined in eq (7)


octahedral shear strain


strain optical coefficient


strain-hardening exponent

r, θ

polar coordinates


distance from crack tip along maximum extension of enclave


arbitrary value to define elastic-plastic boundary


shape of enclave


maximum extension of enclave measured at ɛ1=2000 μin./in


distance from crack tip along line of crack extension


applied stress, gross section


uniaxial yield stress


plate thickness


thickness of photoelastic coating


octahedral shear stress


plastic strain energy in one enclave


plate width


plastic distortional strain energy density


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Copyright information

© Society for Experimental Mechanics, Inc. 1964

Authors and Affiliations

  • William W. Gerberich
    • 1
  1. 1.Philco Research LaboratoryFord Motor Co.Newport Beach

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