Methodology and technological equipment development for treatment processes metal plastic flow research. Part 2. Special equipment and methodology development for experiment research by digital image correlation method

Abstract

The metal plastic flow regularities experimental estimation, as well as the residual stresses (RS) values in the treatment processes is an important task to correctness justification of obtained finite element modeling solutions. However, the currently known and used plastic flow regularities and RS experimental determination methods in most cases have a significant disadvantages: labor intensity, low accuracy, sample preparation necessity and difficult to apply on real parts. This work purpose is to develop special equipment and methods for researches by the digital image correlation method for conducting experimental metal plastic flow and RS researches during free orthogonal cutting and surface plastic deformation (SPD) under the technological treatment factors variation. The paper substantiates orthogonal loading schemes in the metal plastic flow research in the cutting and SPD processes, research accessories and equipment is developed. The machine movement errors were determined, the sample sizes and loading routines were determined and justified. Using the digital image correlation method, the metal plastic flow experimental researches in the deformation zone during free orthogonal cutting and surface plastic deformation processes were performed. For experimental samples RS determinination after free orthogonal cutting and surface plastic deformation, the digital image correlation and probing hole drilling methods combination was used for the first time, which idea is to determine the material particles movements on the sample top from two images: the sample surface having residual stresses and the same surface after high-speed probing hole.