Three-Dimensional Fatigue Crack Growth Analysis Using Failure Mechanism Approach In Ansys
Critical cracks exist mainly on surfaces of mechanical components in engineering. To predict fatigue crack propagation, fatigue crack growth life, and characterization of a surface crack through different simulation tool are widely being implemented. From fracture analysis it is known that the st...
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| Format: | Monograph |
| Language: | English |
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Universiti Sains Malaysia
2019
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| Online Access: | http://eprints.usm.my/58534/ http://eprints.usm.my/58534/1/Three-Dimensional%20Fatigue%20Crack%20Growth%20Analysis%20Using%20Failure%20Mechanism%20Approach%20In%20Ansys.pdf |
| Summary: | Critical cracks exist mainly on surfaces of mechanical components in
engineering. To predict fatigue crack propagation, fatigue crack growth life, and
characterization of a surface crack through different simulation tool are widely being
implemented. From fracture analysis it is known that the stress field in a 3D surface
crack differs from the conventional plane strain tip field. The stress intensity factor
(SIF) depends additionally on crack front curvature, crack edge to free surface, and
structure configuration. Especially, SIF may vary non-proportionally with crack
growth. Predictability and accuracy of the fracture mechanics to 3D surface crack are
still interesting issue for many mechanical parts under different geometry and loading
conditions. So, this thesis proposes Separating, Morphing, Adaptive, and Remeshing
Technology (SMART) which is a new feature available in ANSYS version 19.0 and
above to analyze fatigue crack growth under cyclic loading in 3D analysis. This
research is to evaluate the fatigue crack growth (FCG) life, effect of geometric
discontinuity variation and loading position different on the crack trajectory and fatigue
life respectively. Finite element analysis (FEA) was performed on a test specimen taken
from a published research to obtain the direction of crack propagation under fatigue
loading. The analysis was executed using ANSYS 19.2 under mechanical workbench
platform. The crack propagation on the specimen was simulated using Life-Cycle
Prediction (LC) method under SMART feature. This thesis verifies the validity of this
new feature for crack growth analysis and to portray the effect of geometric
discontinuity variation and different loading application on the crack propagation angle
and specimen fatigue life respectively. It was found that, geometric discontinuity and
loading application variation give a major effect on the crack propagation angle and
specimen’s fatigue life cycle. This also justify that the crack angle and fatigue life is
influenced by loading position, geometric discontinuity and defect that present in the
specimen. |
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