Analysis of Crack Growth Path under Simple and Mixed-Mode Loading in Specimens with Rectangular Section

2016 ◽  
Vol 251 ◽  
pp. 194-199 ◽  
Author(s):  
Sebastian Faszynka ◽  
Dariusz Rozumek
Keyword(s):  
Crack Growth ◽  
Stress Ratio ◽  
Rectangular Cross Section ◽  
Fatigue Tests ◽  
Test Results ◽  
Growth Path ◽  
Rectangular Section ◽  
Α Phase ◽  
Crack Growth Path ◽  
Crack Paths

The paper presents the test results on the fatigue crack growth under bending, torsion and proportional bending with torsion. The tests were performed at the fatigue test stand MZGS-100 at the constant amplitude of moment MB = MT = MBT = 15.84 N⋅m and stress ratio R = -1. Specimens with rectangular cross-section in fatigue tests were used and were made of EN AW-2017A aluminium alloy. The EN AW-2017A alloy consists of α grains and the Al2Cu phase. The effect of the microstructure on the crack paths in specimens was observed. Transcrystalline cracks through grains of the α phase have been usually observed on the fractures.

Thermal Effects while Fatigue Cracking Growth under Bending

2013 ◽  
Vol 592-593 ◽  
pp. 700-703
Author(s):  
Dariusz Rozumek ◽  
Norbert Szmolke
Keyword(s):  
Crack Growth ◽  
Thermal Effects ◽  
Fatigue Cracking ◽  
Fatigue Tests ◽  
Temperature Gradients ◽  
Growth Path ◽  
Temperature Changes ◽  
Crack Growth Path ◽  
Molecular Friction

The paper presents the results of fatigue tests where temperature changes on specimen surfaces were registered. Some different materials were tested. A relation between the crack growth and temperature changes in the propagation place was found. The highest temperature gradients were measured on the crack growth path, and it was caused by molecular friction.

Computational Fatigue Analysis of the Pin-Loaded Lug with Quarter-Elliptical Corner Crack

2017 ◽  
Vol 09 (04) ◽  
pp. 1750058 ◽  
Author(s):  
Slobodanka Boljanović ◽  
Stevan Maksimović ◽  
Andrea Carpinteri ◽  
Boško Jovanović
Keyword(s):  
Crack Growth ◽  
Stress Ratio ◽  
Crack Path ◽  
The Finite Element Method ◽  
Growth Path ◽  
Growth Data ◽  
Corner Crack ◽  
Nonlinear Stress ◽  
Crack Growth Path ◽  
Crack Growth Model

In the present paper, mathematical models based on a new fracture mechanics methodology are developed for the failure analysis of an attachment lug with one/two quarter-elliptical crack(s) emanating from a hole. The strength of lug subjected to cyclic loading is theoretically examined through the following issues: the stress analysis, the estimation of life up to failure and the crack path evolution. The nonlinear stress field along the crack front is simulated by using the [Formula: see text]-integral method together with the finite element method. Furthermore, analytical and numerical methods are employed for the stress intensity factor calculation. The stress-ratio dependence crack growth model is applied in order to evaluate both the life up to failure and the crack growth path. The proposed models are validated through available crack growth data, and the comparison between different results is satisfactory.

Fatigue Crack Growth in Specimens with Rectangular Section under Torsion and Bending with Torsion

2016 ◽  
Vol 250 ◽  
pp. 10-15 ◽  
Author(s):  
Sebastian Faszynka ◽  
Dariusz Rozumek
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Length ◽  
Crack Growth ◽  
Stress Ratio ◽  
Fatigue Cracks ◽  
Experimental Tests ◽  
Test Results ◽  
Constant Amplitude ◽  
Rectangular Section

The paper presents the test results on the fatigue crack growth under torsion and proportional bending with torsion in the aluminium alloy EN AW-2017A-T4. The tests were performed at the fatigue test stand MZGS-100 at the constant amplitude of moment MB = MT = MBT = 15.84 N⋅m and stress ratio R = -1. Plane specimens with stress concentrators in form of the external one-sided blunt notch were tested. The results of experiments were described on graphs of the fatigue crack length „a” versus numbers of cycles N. A non-uniform fatigue cracks growth on both lateral surfaces of specimens was observed during experimental tests.

Crack Growth by Dimensional Reduction Methods

2012 ◽  
Vol 525-526 ◽  
pp. 17-20
Author(s):  
P.H. Wen ◽  
M.H. Aliabadi
Keyword(s):  
Crack Growth ◽  
Dimensional Reduction ◽  
Crack Extension ◽  
Initial Growth ◽  
Stress Criterion ◽  
The Maximum Principle ◽  
Reduction Methods ◽  
Small Increments ◽  
Crack Growth Path ◽  
Crack Paths

This paper presents a new fatigue crack growth prediction by using the dimensional reduction methods including the dual boundary element method (DBEM) and element-free Galerkin method (EFGM) for two dimensional elastostatic problems. One crack extension segment, i.e. a segment of arc, is introduced to model crack growth path. Based on the maximum principle stress criterion, this new prediction procedure ensures that the crack growth is smooth everywhere except the initial growth and the stress intensity factor of mode II is zero for each crack extension. It is found that the analyses of crack paths using coarse/large size of crack extension are in excellent agreement with analyses of the crack paths by the tangential method with very small increments of crack extension.

Capture of 2-D Crack Growth Path by the Polygonal Numerical Manifold Method

2012 ◽  
Vol 166-169 ◽  
pp. 3224-3227
Author(s):  
Hui Hua Zhang
Keyword(s):  
Crack Propagation ◽  
Crack Growth ◽  
High Efficiency ◽  
Numerical Manifold Method ◽  
Growth Path ◽  
Great Flexibility ◽  
Materials Modeling ◽  
Polygonal Elements ◽  
Crack Growth Path ◽  
Numerical Manifold

Due to the independence of physical domain and the mathematical cover system, the numerical manifold method (NMM) can efficiently simulate crack propagation without remeshing. At the same time, the polygonal elements are also very attractive due to their great flexibility in meshing and high efficiency in materials modeling. In the present paper, the NMM is applied to solve 2-D crack propagation problems on polygonal elements. Our numerical results show that the proposed method can well capture the crack growth trajectory compared with the reference solution

Morphology Analysis of Mixed Mode Fatigue Crack Growth in a Low Alloy Steel

2013 ◽  
Vol 787 ◽  
pp. 745-749
Author(s):  
Hui Fang Li ◽  
Xiao Ju Sun ◽  
Lan Qing Tang ◽  
Cai Fu Qian
Keyword(s):  
Fatigue Crack ◽  
Fracture Surface ◽  
Crack Growth ◽  
Alloy Steel ◽  
Mixed Mode ◽  
Low Alloy Steel ◽  
Growth Path ◽  
Fatigue Fracture Surface ◽  
Final Fracture ◽  
Crack Growth Path

In this paper, I+II mixed mode fatigue crack propagation in a low alloy steel 16MnDR was experimentally investigated. Morphologies of crack growth path and fracture surface are analyzed. It is found that upon initiation from the inclined pre-crack, the newly formed crack grows in a direction to be perpendicular to the applied load, making crack mode transformation from I+II mixed mode to mode I. The crack growth is transgranular and no clear branches are presented. Striations and dimples are found on the fatigue fracture surface and the final fracture surface, respectively, showing that the material is ductile in nature.

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