Predicting Steel Tensile Responses and Fracture Using the Phenomenological Ductile Shear Fracture Model

Abstract

In the literature, all the micromechanical fracture models used for predicting structural steel tensile responses and fracture are based on the ductile fracture mechanism that uses the Lode angle parameter to simulate shear fracture under low-stress triaxiality. Using the phenomenological shear fracture model that uses the shear stress ratio rather than the Lode angle parameter, this technical note presents the finite element predictions of the responses of S690 steel solid and perforated coupons under tension and of the fractures of TRIP (transformation-induced plasticity) 690 steel specimens under pure shear and combined shear and tension. The calibrated phenomenological shear fracture model parameters are obtained through a phenomenological curve-fitting process that does not involve costly laboratory tests. This technical note demonstrates that the phenomenological shear fracture model can accurately predict the responses and fracture of structural steels under tension, pure shear, and combined shear and tension.

Block tearing of S700 high strength steel bolted connections: Testing, numerical modelling and design

“…The eight-node brick element C3D8R [21], which has been extensively used in the numerical modelling of metallic bolted connections [9,10,14,[22][23][24][25][26][27][28][29], was employed herein to model the bolts, inner plates and outer plates of the S700 high strength steel bolted connection specimens.…”

“…Damage of the material was triggered when the equivalent plastic strain reached the damage initiation strain. This was followed by the evolution of damage, which was described in terms of the displacement at failure; it is worth mentioning that the value of the displacement at failure was also determined by means of trial and error [9,10,14,28,29] and taken as 0.2 mm herein. Once the equivalent plastic displacement reached the displacement at failure (i.e.…”

“…The standard solver in ABAQUS [21] often encounters convergence problems when applied to FE models containing a large number of contact interactions; this was found to be the case herein. Hence, the explicit solver [21], originally developed for dynamic structural analyses and also shown to be suitable for quasi-static and static structural analyses [9,10,23,28,32], was adopted to analyse the developed S700 high strength steel bolted connection FE models. The step time was taken as 1 s herein, which was sufficient to limit the kinetic energy to no more than 5% of the total internal energy and ensure that the numerical behaviour of the S700 high strength steel bolted connection FE models were essentially static.…”

Finite Element Analysis of Double-Bolt Shear-Out Fracture Failure

“…The details of the phenomenological curve fitting process, which involved the FE tensile testing of the Q550D and Q690D steel grades tension coupons validated with the tension test results in the experimental work of [20] are not presented in this work for brevity. The details of the phenomenological curve fitting process are available in the several published works co-authored by the first author (see [16][17][18]). The general contact (explicit) algorithm with the tangential behaviour, penalty frictional interaction, and a coefficient of friction of 0.15 (a value between the 0.0 and 0.3 employed in the published literature) were employed to model the contact between the steel sheet models and the bolts.…”

“…The details of the isotropic elastic-plastic and the phenomenological shear damage and fracture models are not presented for brevity. Interested readers are referred to [14] and [15], and the several published works of the first author (see [16][17][18][19]) for the details of the isotropic elastic-plastic and the phenomenological shear damage and fracture models.…”