Elastic behaviour characterisation of TRIP 700 steel by means of loading–unloading tests

Characterisation and modelling of in-plane springback in a commercially pure titanium (CP-Ti)

“…Therefore, considering elastic behaviour as a linear curve by using a single value for Young's modulus to describe the elastic region can potentially generate significant uncertainties in determination of springback. This is even more pronounced during unloading compared to loading [1,5,[7][8][9][13][14][15].…”

“…Accurate prediction of springback for such metals is a challenge, particularly for parts with complex geometries. An extensive body of the literature exists on studying springback in different materials, where the origin of springback is linked to the changes in materials mechanical properties and responses during plastic deformation [1,[6][7][8][9][10][11][12].…”

“…Earlier studies [1,7,8,10,11,[13][14][15][16][17] show a degradation in Young's modulus as a function of the level of plastic deformation for different alloys. This has usually been shown by comparing the initial elastic modulus, characterised using standard methods, at no plastic strain to those measured after various levels of plastic strain through interrupted tensile tests, consisting of a series of loading-unloading-loading steps on a same sample [5].…”

“…Different methodologies exist to study degradation in Young's modulus as a function of plastic deformation, such as interrupted uniaxial [1,7,8,[13][14][15]18] and biaxial loading-unloading-loading tensile tests [19,20], and pre-strained three-point bending tests [19,[21][22][23]. The former is the most reported method used for detailed characterisation of elastic modulus during plastic deformation [1,7,8,10,11,[13][14][15][16][17]. Despite the intensive application of interrupted tensile test technique, it has been argued that the pre-strained threepoint bending test provides measurement of degradation in elastic modulus during plastic deformation more accurately [19].…”

“…Benito et al [11] reported & 8% decrease in Young's modulus with 6% plastic deformation in pure iron deformed by drawing at room temperature, followed by a negligible increase in the Young's modulus (& 6 GPa) after further 3% deformation. In a study conducted on TRIP 700 steel by Mendiguren et al [7], the Young's modulus is decreased by 20% after 12% plastic deformation, which raised an alarm on considering this significant change in the prediction of post-forming springback. The level of degradation is shown to vary for different materials.…”