Elastoplastic response and failure assessment of steel alloys: Empirical and computational analyses

Fatigue Fract Eng Mat Struct

Melo

Tavares

et al. 2020

Self Cite

This manuscript investigates the effect of existing slant cracks in finite plates subjected to the mode I loading condition using the stress dead-zone (SDZ) concept. For this purpose, standardised polymeric middle tension (MT) specimens containing slant notches with different orientations were mechanically tested under a unidirectional tensile load. The experimental data were collected and analysed using 3D digital image correlation (DIC) contributing to document the deformation field around slanted cracks and stress intensity factor (SIF) evaluation. Computationally, the fracture model was solved using the finite element method (FEM) to obtain results on the SIF, deformation field and the SDZ characterisations. The obtained SIFs were compared with a reference solution from the literature. An acceptable agreement has been accomplished amongst the results. Furthermore, the SDZ was assessed through deformation field obtained from DIC and FEM.

Section: Model Definitionmentioning

confidence: 99%

A fracture study of slanted cracks using the stress dead‐zone hypothesis

Fatigue Fract Eng Mat Struct

Melo

Tavares

et al. 2020

Self Cite

“…In order to perform the DIC analysis, to build a random pattern, the specimen was coated with a white matt ink and speckled with black dots as can be seen in Figure A. The procedure of DIC analysis followed former relevant works as for example Farahani et al As shown in Figure A, a concentrated load P = 1000.0 N, perpendicular to the crack plane, was prescribed respecting the test system frequency of f = 10.0 Hz. Figure B depicts the anticipated dead zone region (ideal unloaded one) near the crack flanks and also the intended area ahead of the crack tip to be considered in the compliance calculations.…”

Section: Model Definitionmentioning

confidence: 99%

Concept of stress dead zone in cracked plates: Theoretical, experimental, and computational studies

Fatigue Fract Eng Mat Struct

Eslami

Melo

et al. 2019

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This paper presents a study on stress dead zone implications and its characterization with uniaxial tensile testing on MT polycarbonate plate specimens. To obtain the experimental solution, digital image correlation (DIC) is used. Numerically, based on LEFM, the problem is solved using advanced discretization techniques, finite element, and meshless methods. Considering stress dead zone notion, it aims to determine alternative analytical solution of the SIF. Thus, the compliance method is adopted, which is associated with the specimen's dead zone region that does not involve the cracking resistance. Hence, LEFM formulations complying with strain energy release rate criterion are assumed. A proper comparison is made amongst results obtained from all theoretical, experimental, and numerical analyses. Furthermore, this work focuses on the variational fields' evaluation and, in particular, verification on the theoretical assumption of dead zone characteristics. The obtained results support adopted methodologies and are encouragingly robust and cost‐effective.

“…As the literature substantiated, 19,30,[46][47][48] the GTN damage criterion possesses a reasonable efficiency to forecast the damaged region and fracture characteristics such as stress triaxiality (TF), thickness variation, porosity and equivalent plastic strain (PEEQ). Among all, the TF could significantly affect material's stress/strain variation and later on the damage expansion.…”

Section: Fea: Ductile Fracture Predictionmentioning

confidence: 99%

“…16 Stuparu et al 17 adopted DIC to figure out the failure phase of dissimilar single lap joints manufactured from aluminium alloys and carbon fibre adherents considering various thicknesses. DIC was also adopted to study the failure mechanism of metallic alloys resorting to the fracture characterization, 18 damage phenomenon 8,19,20 and elastoplastic response. 7,21 It was also adopted to study how damage can influence on the strength of notched composite laminates.…”

Section: Introductionmentioning

confidence: 99%

Material characterization and damage assessment of an AA5352 aluminium alloy using digital image correlation

The Journal of Strain Analysis for Engineering Design

Amaral

Tavares

et al. 2019

Self Cite

The emergence of reliable material characterization techniques in automotive and aeronautical industries, in particular sheet metal forming, promises to underpin a novel advance in materials research. In this regard, 5xxx series aluminium alloys deliver the largest formability range and can be deformed at room temperature. This study aims at determining the mechanical properties of the AA5352 aluminium alloy, using digital image correlation. Thus, tensile sheet specimens manufactured from the corresponding alloy are mechanically tested under a uniaxial condition and deformation fields are monitored. Considering the force/displacement response and stress/strain curves, the material Poisson’s ratio, Young’s modulus and anisotropy coefficient in the transverse direction are characterized by the experimental digital image correlation data. It intends to obtain accurate and reliable mechanical properties to be considered in the future processing analyses. Numerically, adopting the experimentally obtained material properties, the Gurson–Tvergaard–Needleman damage model is implemented using finite element method formulation to forecast the ductile fracture performance of the tested AA5352 sheet. The predicted results are then compared with the experimental digital image correlation solution verifying good agreement with the force/displacement response and the deformation fields. Overall, the acquired numerical results imply that the Gurson–Tvergaard–Needleman damage criterion is capable to render an accurate prediction upon a high stress triaxiality state.