Compression and Fatigue Testing of High-Strength Thin Metal Sheets by Using an Anti-Buckling Device

Abstract

Background The modelling of the sheet metal forming operations requires accurate and precise data of the material plastic behaviour along non-proportional strain paths. However, the buckling phenomenon severely limits the compressive strain range that could be used to deform thin metal sheets. Objective The main aim of this paper was to propose an effective device, that enables to determine of accurate stress-strain characteristics of thin metal sheet specimens subjected to axial deformation without buckling and with a special emphasis on friction correction. Methods In this paper, an anti-buckling fixture was proposed to assess the deformation characteristics of X10CrMoVNb9-1 (P91) power engineering steel, and DP500 and DP980 dual-phase steels, under compression loading. The fixture enables monitoring of the friction between the specimen and supporting blocks during the test, and thus the precise stress response of the material could be determined. Results The effectiveness of the fixture was evaluated under tension–compression cyclic loading and during the compression tests in which high-strength thin metal sheets were successfully deformed up to 10% without specimen buckling. Furthermore, the successful determination of a friction force variation between supporting blocks and the specimen during tests enabled to determine an actual force acting on the specimen. Conclusions The proposed testing fixture was successfully assessed during the compression and cyclic tension–compression of high-strength thin metal sheets as no buckling was observed. Its advantage lies in adapting to change its length with specimen elongation or shrinkage during a test. The friction force generated from a movement of both parts of the device could be effectively monitored by the special strain gauge system during testing and thus its impact on the stress-strain characteristics could be successfully eliminated.

In Situ Uniaxial Compression of Textured Magnesium AZ31B

“…To constrain the sample during compression to prevent it from buckling, a novel close-fitting anti-buckling guide (ABG) was developed. The ABG fitted closely to the sample without interfering with the mechanical test [41,42], while at the same time allowing for an extensometer to contact the sample and allowing space for the incident and scattered electron beams. So that the same area of the sample could be mapped multiple times without signal degradation due to sample preparation-induced corrosion [43,44] and hydroxide formation [45], a new method of As the mechanical properties of materials are derived from the microstructure, studies of the granular, inter-granular and sub-granular deformation mechanisms form the basis for understanding the material behavior and for predicting properties such as strength, brittleness and ductility [19][20][21][22].…”