Macro strain-stress determination in a high pressure rotational anvil apparatus.

With the increasing development of techniques that utilize high-pressure shear in multiple fields, constructing a proper interpretation of strain and stress in rotational anvil apparatuses is becoming more and more urgent. A macro strain analysis in a rotational anvil apparatus that generates high pressure and shear was performed based on a polycrystal strain spatial distribution. Based on the strain, macro stress components were retrieved. Three analytical methods suitable for various application purposes are presented that can be used to conduct stress/strain analysis of a sample under pressure and shear: a sample center fitting method that obtains macro strain components from the refinement of d-spacing azimuth angle distribution, a six-point graphical method that calculates macro strain components from graphical strain distribution, and a four-point graphical method that determines the components directly from a diffraction image. This study also discusses and verifies the validity of and comparison between the methods through experimental data. The present work is expected to provide a foundation for further experimental studies of shear at pressures and expand the field of high-pressure sciences. [ABSTRACT FROM AUTHOR]