Localisation Phenomenon Investigation on SMATed Stainless Steel Samples by Speckle Interferometry

Abstract

In‐plane Electronic Speckle Pattern Interferometry (ESPI) has been successfully used during tensile tests on SMA‐treated (Surface Mechanical Attrition Treatment) and as‐received 316L stainless steel in order to measure the strain rate field. The heterogeneity in the strain rate field can be observed from a stage of deformation which doesn’t coincide with the classic Considère’s criterion (dF = 0) for the diffuse neck initiation (or plastic instability). The initiation of this heterogeneity strongly depends on treatments undergone by the material. In this paper, a comparison was performed about the heterogeneity initiation of specimens SMATed during 30 min with 2 mm shot, 3 mm shot and a non‐treated sample. The formation of the two slip band system until fracture of the tensile specimen was also studied.

Multilayer modelling of stainless steel with a nanocrystallised superficial layer

“…In order to justify the use of equation (1.4) as starting point for our model, the hypothesis that plane sections remain plane was verified by measuring the deformation through the thickness of the sample at one edge with Electronic Speckle Pattern Interferometry (ESPI) [14][15][16][17].…”

A Closer Look at the Diffuse and Localised Necking of A Metallic Thin Sheet: Evolution of the Two Bands Pattern

“…Applied to in-situ analysis of strain localisation, pioneering work has been carried out by Toyooka and Gong [16,17]. Then it was developed and extended by Madjarova [18] and Yoshida and co-workers [19,20], Guelorget et al [21,22], Montay et al [23,24] and J. Petit et al [25][26][27] regarding to the different modes of loading, different materials and different surface conditions of the specimens. Compared with Digital Image Correlation which depends on the size of the sub-images chosen to calculate the correlation function, ESPI has a one pixel spatial resolution (or 2-3 pixels if a light filtering is applied).…”

Pitting Kinetics of 304 Stainless Steel Using ESPI Detection Technique

“…ESPI is a kind of optical measurement method which is based on laser and optoelectronic techniques and digital image processing. The chief advantages of ESPI are whole field, fast, noncontacting, and especially sensitive in temporal and space resolution [34,35]. It has been recognized as a highly accurate method for measuring surface displacements and has been widely used for deformation measurement and nondestructive tests, such as monitoring tensile and vibration tests, three-dimensional strain measurement and diffusion measurement in biochemical engineering [34][35][36][37][38][39][40].…”