Location

La Jolla, CA

Start Date

1-1-1987 12:00 AM

Description

Previous experiments in our laboratory [1,2] have demonstrated that changes in optical correlation intensity can be used to monitor small strain applied, for example, to aluminum alloy specimens in simple tension. By analyzing data separately for specimen translation, elastic strain, and plastic strain, respectively, we inferred that irreversible changes in correlation intensity associated with plastic strains of the order of 10-3 are caused by accompanying changes in surface topography [2]. In this paper, we present results which link metallographic observations of surface slip and related topographic changes directly to corresponding changes in optical correlation intensity, during uniaxial tensile straining of a stainless steel heat treated to two different initial conditions. The results show that in a given material, correlation intensity is not a unique function of plastic strain, but that it depends on the detailed topographic changes which occur when strain is applied.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

6B

Chapter

Chapter 8: Materials Characterization

Section

Cracks and Deformation

Pages

1625-1632

DOI

10.1007/978-1-4613-1893-4_183

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Evaluation of Strain-Induced Surface Changes by Optical Correlation

La Jolla, CA

Previous experiments in our laboratory [1,2] have demonstrated that changes in optical correlation intensity can be used to monitor small strain applied, for example, to aluminum alloy specimens in simple tension. By analyzing data separately for specimen translation, elastic strain, and plastic strain, respectively, we inferred that irreversible changes in correlation intensity associated with plastic strains of the order of 10-3 are caused by accompanying changes in surface topography [2]. In this paper, we present results which link metallographic observations of surface slip and related topographic changes directly to corresponding changes in optical correlation intensity, during uniaxial tensile straining of a stainless steel heat treated to two different initial conditions. The results show that in a given material, correlation intensity is not a unique function of plastic strain, but that it depends on the detailed topographic changes which occur when strain is applied.