Analysis of ductile damage and fracture under reverse loading

Wei, Zhichao; Zistl, Moritz; Gerke, Steffen; Brünig, Michael

doi:10.1016/j.ijmecsci.2022.107476

Cited by 26 publications

(40 citation statements)

References 54 publications

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“…From Tables 4 and 5, and Figures 2 and 3, it is clear that as the lateral compressive stress increases Young's modulus reduces, generally (a reverse of the hydrostatic case). This is one point where Saint Venant's theory failed, in not accounting for hydrostatic effects, which tend to strengthen the material to sustain higher loads than indicated by that theory (Wei, 2022;He, et al, 2014;Karp & Durban, 2011). In the actual experiments, it is observed that rupture in most of the biaxial cases occurred at the point of application of the lateral stress.…”

Section: Discussionmentioning

confidence: 98%

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Concept of Equivalent Stress Criterion For Predicting Failure of Brittle Materials

Sackey

Ngewana

2022

AJAR

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Purpose: A paucity of proven failure criteria for brittle engineering materials exists, and this paper intends to present and validate a novel concept of equivalent stress criterion for predicting the failure of brittle isotropic homogeneous materials based on the concept of effective causative failure stress. Design/Methodology/Approach: Mathematical modelling is first performed based on strain-state equivalence, followed by conversion to the equivalent causative stress. The model is then validated with experimental and other data and with comparisons to traditional models. The material studied is BS 1452 Grade 250 continuous-cast grey cast iron with a Young’s Modulus of 39 000 MPa and ultimate tensile strength of 290 MPa. The test samples were prepared square in shape 12 mm x 12 mm to enable stresses in two perpendicular directions. Data is generated from uniaxial and bi-axial tests, performed using a standard universal testing machine, INSTRON 880, improvised to enable bi-axial recordings. Findings: Results point consistently to higher fidelity and transparency of the new model in representing the state of stress, especially in the second and fourth quadrants of the principal stress diagram, where Rankine’s criterion completely ignores stress differences and Mohr handles shear stresses in a suboptimal fashion. Both the maximum principal stresses and maximum shear stresses predicted by the proposed model are found to be somewhat greater than those from the traditional models, indicating higher accuracy and greater aggressiveness in prediction. The findings have further revealed that shearing effects play a greater role in the failure of engineering brittle materials than traditional failure theories have considered. Research Limitation: The study involved improvisation to enable biaxial stress recordings. This process was not perfect, resulting in smaller-than-ideal values of the lateral stresses. Practical implication: The study recommended process and equipment development toward perfecting multiaxial tests. Social implication: The survey will enrich the literature with pertinent design methodology to help in product design, including social-interest products. Originality / Value: Since truly homogeneous materials are known to withstand very high hydrostatic pressures, direct stresses alone do not constitute valid failure criteria for all loading conditions.

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Section: Discussionmentioning

confidence: 98%

“…It was widely recognized and applied to engineering practice for many decades (He et al, 2014). The theory had the advantage that strains are often easier to measure than stresses Despite this, it became defunct due to its failure to account for hydrostatic effects and shear-stress effects (Wei, Zistl, Gerke, & Brünig, 2022).…”

Section: Introductionmentioning

confidence: 99%

Concept of Equivalent Stress Criterion For Predicting Failure of Brittle Materials

Sackey

Ngewana

2022

AJAR

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“…where T represents the effective Kirchhoff stress tensor, ᾱ is the effective back stress tensor, the hydrostatic stress coefficient is measured as a/c = 32 TPa −1 [8], and c depicts the equivalent yield stress. Furthermore, an extended Voce hardening law for isotropic hardening…”

Section: Constitutive Modelingmentioning

confidence: 99%

“…The aim of this work is to find the mentioned stress-state-dependent parameters suitable for a wide class of the ductile metals, and the micro-numerical analysis and corresponding material parameters have been presented by Brünig et al [10]. Most important, those parameters have been validated by doing series of experiments and numerical simulations with different metals: for aluminum alloy EN-AW 6082 [7,8] and ductile steel X5CrNi18-10 [11].…”

Section: Parameter Identificationmentioning

confidence: 99%

Analysis of ductile damage evolution and failure mechanisms due to reverse loading conditions for the aluminum alloy EN‐AW 6082‐T6

Wei

Zistl

Gerke

et al. 2023

Proc Appl Math and Mech

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This paper deals with experiments and numerical simulations for reverse uniaxial tension‐compression and shear tests to investigate the ductile damage and fracture behavior of the aluminum alloy EN‐AW 6082‐T6. For this purpose, experiments with different loading sequences and number of loading cycles with uniaxial tensile and new shear specimens have been performed. Furthermore, the digital image correlation (DIC) technique captures the deformations and strain fields during the experimental processes. A modified anisotropic stress‐state‐dependent elastic‐plastic‐damage continuum model is proposed and is validated by experimental strain fields measured by DIC. Moreover, numerically predicted distributions of the principal damage strains are compared with fracture images taken by scanning electron microscopy (SEM).

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“…For geomaterials [3] as well as some metals [4] whose behaviours exhibit a strong dependence on the hydrostatic pressure, the yield function adopted in the constitutive equations should include a pressure-sensitivity. One of the most widely accepted criteria is the Drucker-Prager yield criterion as its structure is quite simple [5].…”

Section: Introductionmentioning

confidence: 99%

A two‐surface damage‐plasticity model based on a Drucker—Prager yield criterion

Zhang

Brepols

Reese

2023

Proc Appl Math and Mech

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A gradient-extended two-surface damage-plasticity model based on a von Mises yield criterion has been proposed by [1,2], which can be flexibly adapted to (quasi-)brittle-like, ductile-like, or various material behaviors in between. However, the von Mises yield criterion does not take into account the effect of hydrostatic pressure, therefore it can hardly model the failure behavior of pressure-sensitive materials such as geomaterials and some metals. For this reason, a pressure-dependent twosurface damage-plasticity model based on the Drucker-Prager yield criterion is proposed in the current work, and the nonlinear hardening is also included. Plasticity and damage are treated as distinct but coupled dissipative phenomena by a two-surface approach. Furthermore, the numerical implementation of the Drucker-Prager yield criterion is discussed in this study, and the return mapping procedures of the smooth portion and the vertex of the cone are discussed in detail.

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Analysis of ductile damage and fracture under reverse loading

Cited by 26 publications

References 54 publications

Concept of Equivalent Stress Criterion For Predicting Failure of Brittle Materials

Concept of Equivalent Stress Criterion For Predicting Failure of Brittle Materials

Analysis of ductile damage evolution and failure mechanisms due to reverse loading conditions for the aluminum alloy EN‐AW 6082‐T6

A two‐surface damage‐plasticity model based on a Drucker—Prager yield criterion

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