Fatigue Crack Growth Life Prediction for Surface Crack Located in Stress Concentration Part Based on 3D-FEM

2002 ◽  
Author(s):  
Youichi Yamashita ◽  
Masaharu Shinozaki ◽  
Yuusuke Ueda ◽  
Kenji Sakano
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Surface Crack ◽  
Influence Function ◽  
Fe Analysis ◽  
3D Fem ◽  
Paris Law ◽  
Influence Function Method

Fatigue crack growth prediction methods using three dimensional finite element analyses were investigated to improve the predictability of part-through surface crack growth life. First, a direct analysis method of cyclic finite element analysis was adopted. Fatigue crack growth was predicted on a step by step basis from the Paris’ law using stress intensity factor range (ΔK) calculated by 3D-FEM. This method takes the procedure of cyclic operation of FE-analysis modeled with crack tip elements, crack growth increment calculation and remeshing of FE-model. Second, a method based on influence function method for ΔK calculation directly using 3D-FE-analysis result has been developed and applied. It was found that crack growth prediction based on step by step finite element method and the method based on the influence function method showed good correlation with the experimental results if Paris’ law coefficient C determined by CT specimen was appropriately used for semi-elliptical surface crack.

Augmenting Generic Fatigue Crack Growth Models Using 3D Finite Element Simulations and Gaussian Process Modeling

2019 ◽  
Author(s):  
Adrian Loghin ◽  
Shakhrukh Ismonov
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Propagation ◽  
Gaussian Process ◽  
Crack Growth ◽  
Life Assessment ◽  
Growth Path ◽  
3D Fem

Abstract Assessing the crack propagation life of components is a critical aspect in evaluating the overall structural integrity of a mechanical structure that poses a risk of failure. Engineers often rely on industry standards and fatigue crack growth tools such as NASGRO [1] and AFGROW [2] to perform life assessment for different structural components. A good understanding of material damage tolerant capabilities, and the component’s loading mission during service conditions are required along with the availability of generic fracture mechanics models implemented in the lifing tools. Three-dimensional (3D) linear elastic fracture mechanics (LEFM) finite element modeling (FEM) is also a viable alternative to simulate crack propagation in a component. This method allows capturing detailed geometry of the component and representative loading conditions which can be crucial to accurately simulate the three dimensionality of the propagating crack shape and further determine the associated loading cycles. In comparison to a generic model, the disadvantage of the 3D FEM is the extended runtime. One feasible way to benefit from 3D modeling is to employ it to understand the crack front evolution and growth path for the representative loading condition. Mode I stress intensity factors (KI) along the predetermined crack growth path can be generated for use in fatigue crack growth tools such as NASGRO. In the current study, such a 3D FEM lifing process is presented using a classical bolt-nut assembly, components that are commonly used in engineering design. First, KI solutions for a fixed crack aspect ratio a/c = 1 are benchmarked against a similar solution available in NASGRO. Next, a predefined set of crack shapes and sizes are simulated using 3D FEA. A machine learning model Gaussian Process (GP) was trained to predict the KI solutions of the 3D model, which in turn was used in the crack propagation simulation to accelerate the life assessment process. Verification of the implemented procedure is done by correlating the crack growth curves predicted from GP to the results obtained directly from 3D FE crack propagation method.

Fatigue Crack Growth Prediction of Elliptical Corner Crack Using 3D FEM

2012 ◽  
Vol 248 ◽  
pp. 469-474
Author(s):  
M.H. Gozin ◽  
M. Aghaie-Khafri
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Crack Front ◽  
Crack Opening ◽  
3D Fem ◽  
Corner Crack ◽  
Closure Method

Plasticity induced crack closure (PICC) simulation using finite element analyses has been concerned by many researchers. In the present investigation elliptical corner fatigue crack growth from a hole was predicted using PICC method. An elastic-plastic finite element model is built with a suitably refined mesh and time-dependent remote tractions are applied to simulate cyclic loading. In a 3D geometry the crack opening value will vary along the crack front. For simplicity this shape evolution is neglected and the crack front is extended uniformly. Predicted fatigue life using crack closure method for elliptical corner crack is in good agreement with the experimental data. The results obtained highlighted the sensitivity of crack closure method to the opening stress intensity values.

Fatigue Crack Growth Life Prediction for Surface Crack Located in Stress Concentration Part Based on the Three-Dimensional Finite Element Method

2004 ◽  
Vol 126 (1) ◽  
pp. 160-166 ◽  
Author(s):  
Y. Yamashita ◽  
M. Shinozaki ◽  
Y. Ueda ◽  
K. Sakano
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Surface Crack ◽  
Three Dimensional ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Element Method

Fatigue crack growth prediction methods using three-dimensional finite element analyses were investigated to improve the predictability of part-through surface crack growth life. First, a direct analysis method of cyclic finite element analysis was adopted. Fatigue crack growth was predicted on a step by step basis from the Paris’ law using stress intensity factor range ΔK calculated by the three-dimensional finite element method. This method takes the procedure of cyclic operation of finite element analysis modeled with crack tip elements, crack growth increment calculation and remeshing of the finite element model. Second, a method based on the influence function method for the ΔK calculation directly using three-dimensional finite element method analysis result has been developed and applied. It was found that crack growth prediction based on the step by step finite element method and the method based on the influence function method showed good correlation with the experimental results if Paris’ law coefficient C, determined by CT specimen, was appropriately used for a semi-elliptical surface crack.

Finite Element Simulation of Stable Fatigue Crack Growth Using Critical CTOD Determined by Preliminary Finite Element Analysis

2014 ◽  
Vol 891-892 ◽  
pp. 1675-1680
Author(s):  
Seok Jae Chu ◽  
Cong Hao Liu
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Finite Element Simulation ◽  
Crack Growth ◽  
Crack Tip ◽  
Stress Intensity Factor Range ◽  
Crack Tip Opening Displacement ◽  
Element Analysis ◽  
Element Simulation

Finite element simulation of stable fatigue crack growth using critical crack tip opening displacement (CTOD) was done. In the preliminary finite element simulation without crack growth, the critical CTOD was determined by monitoring the ratio between the displacement increments at the nodes above the crack tip and behind the crack tip in the neighborhood of the crack tip. The critical CTOD was determined as the vertical displacement at the node on the crack surface just behind the crack tip at the maximum ratio. In the main finite element simulation with crack growth, the crack growth rate with respect to the effective stress intensity factor range considering crack closure yielded more consistent result. The exponents m in the Paris law were determined.

Fatigue crack growth of filament wound GRP pipes with a surface crack under cyclic internal pressure

2008 ◽  
Vol 43 (16) ◽  
pp. 5569-5573 ◽  
Author(s):  
Ahmet Samanci ◽  
Ahmet Avci ◽  
Necmettin Tarakcioglu ◽  
Ömer Sinan Şahin
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Internal Pressure ◽  
Crack Growth ◽  
Surface Crack ◽  
Filament Wound
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