A new microvoid-damage model for ductile fracture

1986 ◽  
Vol 25 (3) ◽  
pp. 377-384 ◽  
Author(s):  
Wei Hua Tai ◽  
Bing Xian Yang
Keyword(s):  
Ductile Fracture ◽  
Damage Model

Numerical Investigation of Ductile Fracture in Pipelines Under Complex Loading Using a Phenomenological Damage Model

2021 ◽  
Author(s):  
Iago S. Santos ◽  
Diego F. B. Sarzosa
Keyword(s):  
Ductile Fracture ◽  
Mechanical Response ◽  
Numerical Study ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Numerical Procedure ◽  
Complex Loading ◽  
Experimental Tests ◽  
Compact Tension ◽  
Axial Tensile

Abstract This paper presents a numerical study on pipes ductile fracture mechanical response using a phenomenological computational damage model. The damage is controlled by an initiation criterion dependent on the stress triaxiality and the Lode angle parameter, and a post-initiation damage law to eliminate each finite element from the mesh. Experimental tests were carried out to calibrate the elastoplastic response, damage parameters and validate the FEM models. The tested geometries were round bars having smooth and notched cross-section, flat notched specimens under axial tensile loads, and fracture toughness tests in deeply cracked bending specimens SE(B) and compact tension samples C(T). The calibrated numerical procedure was applied to execute a parametric study in pipes with circumferential surface cracks subjected to tensile and internal pressure loads simultaneously. The effects of the variation of geometric parameters and the load applications on the pipes strain capacity were investigated. The influence of longitudinal misalignment between adjacent pipes was also investigated.

Ductile Tearing Simulation of Circumferential Cracked Pipe Under Cyclic Loading Using Damage Criteria Determined by Monotonic Pipe Test Data

2018 ◽  
Author(s):  
Jin-Ha Hwang ◽  
Gyo-Geun Youn ◽  
Naoki Miura ◽  
Yun-Jae Kim
Keyword(s):  
Fracture Toughness ◽  
Cyclic Loading ◽  
Ductile Fracture ◽  
Test Data ◽  
Strain Energy ◽  
Fracture Strain ◽  
Damage Model ◽  
Fracture Toughness Test ◽  
Ductile Tearing ◽  
Damage Criteria

To evaluate the structural integrity of nuclear power plant piping, it is important to predict ductile tearing of circumferential cracked pipe from the view point of Leak-Before-Break concept under seismic conditions. CRIEPI (Central Research Institute of Electric Power Industry) conducted fracture test on Japanese carbon steel (STS410) circumferential through-wall cracked pipes under monotonic or cyclic bending load in room temperature. Cyclic loading test conducted variable experimental conditions considering effect of stress ratio and amplitude. In the previous study, monotonic fracture pipe test was simulated by modified stress-strain ductile damage model determined by C(T) specimen fracture toughness test. And, ductile fracture of pipe under cyclic loading simulated using damage criteria based on fracture strain energy from C(T) specimen test data. In this study, monotonic pipe test result is applied to determination of damage model based on fracture strain energy, using finite element analysis, without C(T) specimen fracture toughness test. Ductile fracture of pipe under variable cyclic loading conditions simulates using determined fracture energy damage model from monotonic pipe test.

A void evolution-based damage model for ductile fracture of metallic materials

2019 ◽  
Vol 04 (04) ◽  
pp. 1950008
Author(s):  
He Gong ◽  
Changhong Chen ◽  
Yao Yao
Keyword(s):  
Ductile Fracture ◽  
Damage Mechanics ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Metallic Materials ◽  
Numerical Predictions ◽  
Void Evolution ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
1045 Steel

A modified damage model is developed for describing ductile fracture of metallic materials by introducing damage variables with respect to porosity. Based on the geometric characteristics of the void deformation process, modified governing equations of void evolution are proposed to reduce the dependence of micro parameters. A transformed variable is introduced to incorporate the porosity into continuum damage mechanics. The numerical predictions are compared with experimental results for AISI-1095, AISI-1090 and AISI-1045 steel.

Establishment of Unified Correlation of In-Plane and Out-of-Plane Constraints with Ductile Fracture Toughness of Steel

2016 ◽  
Vol 853 ◽  
pp. 22-27 ◽  
Author(s):  
Bo Rui Yan ◽  
G.Z. Wang ◽  
Fu Zhen Xuan ◽  
Shan Tung Tu
Keyword(s):  
Fracture Toughness ◽  
Ductile Fracture ◽  
Structural Integrity ◽  
Damage Model ◽  
Equivalent Plastic Strain ◽  
Specimen Thickness ◽  
Wide Range ◽  
Out Of Plane ◽  
Correlation Line ◽  
Ductile Fracture Toughness

In this paper, the finite element method (FEM) based on GTN damage model was used to obtain ductile fracture toughness and investigate the establishment method of unified correlation of in-plane and out-of-plane constraints with ductile fracture toughness of steels. The unified constraint parameter Ap at different equivalent plastic strain (εp) isolines has been calculated and analyzed for SEN(B) specimens with a wide range of in-plane and out-of-plane constraints. The results show that the average Ap along the specimen thickness (Apave) can well characterize a wide range of in-plane and out-of-plane constraints. The suitable εpisolines range for establishing the unified correlation between Apave and ductile fracture toughness of the steel has been obtained. For the specimens with lower constraint, the higher εp values should be used. The results also show that the correlation line of JC/Jref-Apave1/2is independent of the selections of the suitable εp isolines and the reference specimen. This may bring convenience for the establishment and application of the JC/Jref-Apave1/2correlation lines. Using ductile fracture toughness data of a small number of specimens with different constraints (such as three specimens with different a/W) together with FEM calculations of the parameter Ap, the correlation line of JC/Jref-Apave1/2can be established. The correlation line may be used in structural integrity assessments incorporating both in-plane and out-of-plane constraints.

Characterization of Notched Ductile Failure With Continuum Damage Mechanics

1990 ◽  
Vol 112 (4) ◽  
pp. 412-421 ◽  
Author(s):  
C. L. Chow ◽  
K. Y. Sze
Keyword(s):  
Ductile Fracture ◽  
Circular Hole ◽  
Damage Mechanics ◽  
Damage Model ◽  
Ductile Failure ◽  
Continuum Damage Mechanics ◽  
Thin Plates ◽  
Continuum Damage ◽  
Anisotropic Model ◽  
Aluminum Alloy 2024

A recently developed anisotropic model of continuum damage mechanics has been applied successfully to characterize ductile fracture of cracked plates under mode I and mixed mode failures. The damage model is further extended in this investigation to examine its applicability to include notch ductile fracture of thin plates containing a circular hole. Two hole sizes of 16 mm and 24 mm diameters are chosen and the specimen material is aluminum alloy 2024-T3. Fracture loads of the plates are predicted by the damage model and compared satisfactorily with those determined experimentally. This investigation provides an important confirmation that not only the anisotropic model of continuum damage mechanics but also the same failure criterion developed can be effectively employed to characterize both ductile fracture for plates containing an isolated macro-crack or circular hole which would otherwise not be possible using the conventional theory of fracture mechanics. The successful development of the unified approach to characterize ductile failure provides a vital impetus for design engineers in the general application of the theory of continuum damage mechanics to solve practical engineering problems.

scholarly journals Comparison of MMC and BW fracture models for constructing 3D ductile fracture envelope of AA6063 during cold forming

2020 ◽  
Author(s):  
Jianye Gao ◽  
Tao He ◽  
Yuanming Huo ◽  
Miao Song ◽  
Tingting Yao ◽  
...  
Keyword(s):  
Ductile Fracture ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Compression Tests ◽  
Cold Forming ◽  
Tension Tests ◽  
Wide Range ◽  
Round Bar ◽  
Fracture Models ◽  
Fracture Envelope

Abstract The 3D ductile fracture envelopes of AA6063-T6 was developed to predict and prevent its fracture. Smooth round bar (SRB) tension tests were carried out to characterize the flow stress, and a series of experiments were conducted to characterize the ductile fracture firstly, such as notched round bar (NR) tension tests, compression tests and torsion tests. These tests cover a wide range of stress triaxiality (ST) and Lode parameter (LP) to calibrate the ductile fracture criterion. Plasticity modeling was performed, and the predicted results were compared with corresponding experimental data to verify the plasticity model after these experiments. Then the relationship between ductile fracture strain and ST with LP was constructed using the modified Mohr–Coulomb (MMC) model and Bai and Wierzbicki (BW) model to develop the 3D ductile fracture envelope. Finally, a new ductile damage model was proposed based on the 3D fracture envelope of AA6063. The final results show that the predicted results from the proposed ductile fracture model showed good agreement with experimental results.

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