Implications of macroscopic failure criteria which are independent of hydrostatic stress

1975 ◽  
Vol 11 (3) ◽  
pp. 540-543
Author(s):  
C. T. Candland
Keyword(s):  
Hydrostatic Stress ◽  
Failure Criteria ◽  
Macroscopic Failure

Physicomechanical approaches to an analysis of macroscopic failure criteria. Report 3. Brittle failure

1989 ◽  
Vol 21 (7) ◽  
pp. 841-852 ◽  
Author(s):  
G. P. Karzov ◽  
B. Z. Margolin ◽  
V. A. Shvetsova
Keyword(s):  
Brittle Failure ◽  
Failure Criteria ◽  
Macroscopic Failure

Ductile Failure Analyses for API X65 Pipes Based on Local Failure Criteria

2006 ◽  
Author(s):  
Chang-Kyun Oh ◽  
Yun-Jae Kim ◽  
Jong-Hyun Baek ◽  
Young-Pyo Kim ◽  
Woo-Sik Kim
Keyword(s):  
Experimental Data ◽  
Failure Criterion ◽  
Hydrostatic Stress ◽  
Stress Triaxiality ◽  
Ductile Failure ◽  
Failure Criteria ◽  
Local Failure ◽  
Defective Region ◽  
Api X65 Steel ◽  
X65 Steel

A local failure criterion for the API X65 steel is applied to predict ductile failure of full-scale API X65 pipes with simulated corrosion and gouge defects under internal pressure. The local failure criterion is the stress-modified fracture strain for the API X65 steel as a function of the stress triaxiality (defined by the ratio of the hydrostatic stress to the effective stress). Based on detailed FE analyses with the proposed local failure criteria, burst pressures of defective pipes are estimated and compared with experimental data. The Failure of corroded pipes is governed by local necking and plastic collapse in the defective region, rather than failure. For pipes with gouge defects, on the other hand, it is found that fracture is dominant. The predicted burst pressures are in good agreement with experimental data. Noting that an assessment equation against the gouge defect is not yet available, parametric study is performed, from which a simple equation is proposed to predict burst pressure for API X65 pipes with gouge defects.

scholarly journals Mode-Independent and Mode-Interactive Failure Criteria for Unidirectional Composites Based on Strain Energy Density

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2813
Author(s):  
Nian Li ◽  
Cheng Ju
Keyword(s):  
Failure Mode ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Axial Loading ◽  
Failure Criteria ◽  
Physical Reality ◽  
Failure Envelopes ◽  
Wide Range ◽  
Axial Compressive Stress ◽  
Macroscopic Failure

The strain energy released plays a crucial role in generating macroscopic failure in unidirectional (UD) composites. This paper proposes two new strain energy-based failure criteria, regarding fiber-dominated and matrix-dominated failure mode as independent and interactive, respectively. The failure expression is formulated based on rigorous mathematical deducing, accompanied by physical interpretation. Based on the lack of experimentally feasible multi-axial strengths, a predefined assumption of infinite strength under bi-axial and tri-axial compressive stress provides the possibility for determining all coefficients only by using conventional uniaxial strengths. The failure envelopes predicted by the proposed criteria have been validated against experimental results under biaxial, off-axis and tri-axial loading cases. A better agreement with physical reality was achieved by the failure mode-interactive criterion, suggesting a wide range of applicability.

Modeling and Simulation of the Failure and Stiffness Degradation of a Graphite Epoxy in a Three Point Bending Test

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
E. H. Irhirane ◽  
M. Abousaleh ◽  
J. Echaabi ◽  
M. Hattabi ◽  
A. Saouab ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Experimental Approach ◽  
Failure Modes ◽  
Failure Criteria ◽  
Bending Test ◽  
Geometrical Parameters ◽  
Three Point Bending ◽  
Stiffness Reduction ◽  
Biaxial Tests ◽  
Macroscopic Failure

The use of composite materials with continuous fibers in the aeronautic and aerospace industries requires reliable and precise methods for the prediction of failure. Predicting failure stresses and failure modes in composite laminates is very difficult. The choice between failure criteria is complex, and there is a lack of experimental study to validate the result obtained partly because the biaxial tests are still difficult to perform. This work employs a mixed methodology based on a theoretical and an experimental approach to develop a procedure for the choice and the validation of the failure criterion. The comparison is concerned not only with the macroscopic failure but also with the succession of the failure, the failure mode, and the effect of the geometrical parameters of the test specimen. The most general failure criteria are tested by using two approaches of the stiffness reduction. A finite element code has been elaborated within our laboratory for postfailure treatment. The numerical simulation results are compared with the experimental ones and permit us to make a conclusion on the validity of the failure criteria used.

Modelling of superplastic deformation for metallic alloys using a cavity based approach

2017 ◽  
Vol 2 (81) ◽  
pp. 61-69
Author(s):  
M. Hedayati Marzbali
Keyword(s):  
Superplastic Deformation ◽  
Hydrostatic Stress ◽  
Deformation Characteristic ◽  
Failure Criteria ◽  
Time Algorithm ◽  
Metallic Alloys ◽  
Finite Element Software ◽  
Pressure Time ◽  
Failure Predictions ◽  
Aluminum 5083

Purpose: In this study, modeling of superplastic deformation characteristic for metallic alloys was investigated using GTN failure criteria in viscoplastic framework. Design/methodology/approach: The proposed model studied the simultaneous effects of cavitation and deformation parameter and considered the effects of strain hardening, static and dynamic recoveries, and hydrostatic stress. This cavity based model was then implemented in a creep subroutine in ABAQUS 6.12 finite element software. Findings: Experimental results of Aluminum 5083 from different studies were used to verify the model and evaluate its reliability. Afterwards, numerical simulations for uniaxial tension were performed, and good agreement between experimental and modeling results was obtained. Research limitations/implications: This study showed that using a viscoplastic framework with a cavity criterion ensures more precise pressure-time algorithm, lower deformation time and better failure predictions. These capabilities provides forming more complex parts and different geometries. Accordingly, applying this model is recommended to predict the behaviour of other metallic superplastic alloys.

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