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Numerical Analysis on Fatigue Crack Growth at Negative and Positive Stress Ratios
Abdulnaser M Alshoaibi1, Yahya Ali Fageehi1
1Mechanical Engineering Department, Jazan University, Jazan 45142, Saudi Arabia.
Materials (Basel, Switzerland)
|May 27, 2023
Summary
This study used the finite element method to analyze how stress ratio affects fatigue crack growth. Higher stress ratios significantly increase fatigue life by reducing stress intensity and von Mises stress.
Area of Science:
- Mechanical Engineering
- Materials Science
- Computational Mechanics
Background:
- Fatigue crack propagation is a critical failure mechanism in engineering components.
- Understanding the influence of stress ratio is essential for accurate fatigue life prediction.
- Linear elastic fracture mechanics provides a framework for analyzing crack behavior.
Purpose of the Study:
- To investigate the effect of various stress ratios (positive and negative) on fatigue crack propagation.
- To analyze the relationship between stress ratio, stress intensity factor, and fatigue life.
- To evaluate the impact of stress ratio on von Mises stress distribution.
Main Methods:
- Finite element method (FEM) using ANSYS Mechanical R19.2.
- Application of separating, morphing, and adaptive remeshing technologies (SMART).
- Mixed-mode fatigue simulations on a modified four-point bending specimen with a non-central hole.
Main Results:
- Equivalent stress intensity factor (ΔKeq) decreases with increasing stress ratio.
- Stress ratio significantly influences fatigue life and von Mises stress distribution.
- Increased stress ratio leads to decreased von Mises stress and increased fatigue life cycles.
Conclusions:
- The stress ratio is a critical parameter in fatigue crack propagation.
- Numerical results align with existing experimental and simulation data.
- This research provides valuable insights for designing components subjected to cyclic loading.
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