1. Scope

1.1 This test method covers measurements of direction of principal strains, 1 and 2 , and the photoelastic retardation, , using a compensator, for the purpose of analyzing strains in transparent or translucent plastic materials. This test method can be used to measure birefringence and to determine the difference of principal strains or normal strains when the principal directions do not change substantially within the light path.

1.2 In addition to the method using a compensator described in this test method, other methods are in use, such as the goniometric method (using rotation of the analyzer) mostly applied for measuring small retardation, and expressing it as a fraction of a wavelength. Nonvisual methods employing spectrophotometric measurements and eliminating the human judgment factor are also possible.

1.3 Test data obtained by this test method is relevant and appropriate for use in engineering design.

1.4 The values stated in either SI units or inch-pound units are to be regarded as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

There is no known ISO equivalent to this test method.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D618 Practice for Conditioning Plastics for Testing

D638 Test Method for Tensile Properties of Plastics

D882 Test Method for Tensile Properties of Thin Plastic Sheeting

D4000 Classification System for Specifying Plastic Materials

E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

Keywords

birefringence; photoelastic measurements; photoelastic retardation; strain; strain-optical constant; transparent plastics; Birefringence; Color--plastics; Deformation--plastics; Light transmission and reflection; Photoelastic measurement; Plastic sheet and film; Polariscopic examination; Reflectance and reflectivity; Refractive index; Residual strains; Retardation; Strain testing--plastics; Stress--plastics; Transparent plastics;

ICS Code

ICS Number Code 83.080.01 (Plastics in general)

DOI: 10.1520/D4093-95R05E01

ASTM International is a member of CrossRef.