
•Overview
•Stress Concentrations Around Cracks
•Modes of Loading
•Stress Intensity Factor
•Stress Intensity Factor Solutions
•Superposition for Combined Loading
•Fracture Toughness
•Fracture Toughness vs. Thickness
•Fracture Toughness vs. Strength
•Static Fracture Analysis Methods
•Linear Elastic Fracture Mechanics (LEFM)
•Fatigue Crack Growth
Explore how cracks concentrate stress, with an elliptical crack in an infinite plate; sigma max equals nominal stress times a curvature factor, revealing a stress singularity that plastic deformation mitigates.
Explore the stress intensity factor k, which characterizes the crack-tip stress field and predicts crack growth under mode one loading, with note on finite element estimates for complex cases.
Explore how time-varying loads cause fatigue crack growth, linking stress intensity range to the growth rate beyond the material's threshold via Paris law and the constants c and m.
•Discretization
•Shape functions definition
•Global matrix equation
•Post processing
•Basic XFEM formulation
•Crack Modelling
•Enrichment functions
•The Heaviside jump function
•Asymptotic crack-tip function
•Signed distance function
•Level set method
Explore fatigue crack growth relationships from threshold to rapid growth, and compare Paris, Walker, and comprehensive models for stress ratio and loading effects.
Predict life under cyclic loading by comparing maximum stress intensity to fracture toughness and considering yielding, then iteratively estimate cycles to failure and the factor of safety.
Create a deformable port in the port module using sketches, dimensions, and extrudes; add through-all cuts and holes to build a solid part, then explore the part creation module.
Define isotropic linear elastic material in Abaqus/CAE, set damage initiation via maximum principal stress, configure traction-separation damage evolution, and manage mixed-mode fracture energy for convergence.
Control Abaqus/CAE fracture and fatigue solution accuracy by tuning iterations, residuals, and time points. Use default 200 iterations, adaptive Fourier terms, and equilibrium checks to drive convergence.
Edit residual ratios and time incrementation in a loading step, then request restored analysis to continue interrupted runs by defining restart frequency, overlay options, and restarting from chosen increments.
Learn low cycle fatigue under high stress using direct cyclic analysis, continuum damage mechanics for ductile materials, and fracture mechanics with xfem for brittle materials, including crack growth and delamination.
Define spatial cracks with the extended finite element method in the interaction module, enabling crack initiation and propagation without remeshing using phantom nodes and VCD and Paris law criteria.
Define displacement-controlled loading and boundary conditions in abaqus cae, apply u2, and create tabular amplitude with rayleigh parameters; then mesh, run the analysis, and inspect results.
Explores case study 1: the compact tension specimen using abaqus cae, detailing geometry, boundary conditions, material properties for s355 steel, paris law implementation, and crack growth analysis under fatigue.
Explore Abaqus CAE, a five-part artificial hip joint assembly, including bone, cement, cup, bowl, and stem, and analyze static and fatigue behavior with crack growth.
Perform static analysis to calculate the stress intensity factor for stationary cracks. Use the geometric correction factor to derive delta k from stress and crack geometry.
Fatigue represents the most common cause of mechanical structure failures. To investigate this phenomenon, studies have conducted experiments, conducting actual fatigue experiments demands extensive time, substantial financial resources, and is constrained by size limitations. The solution lies in the development and validation of precise numerical models. This is the primary driver behind our course, as it enables accurate and reliable predictions of crack growth. This course delves into the advanced simulation of fatigue crack growth using the eXtended Finite Element Method (XFEM) combined with the Paris Law formulation, fully implemented in ABAQUS software. The course emphasizes the direct cyclic and low cycle fatigue approaches, providing a comprehensive framework for analyzing the degradation of materials under cyclic loading.
You Will Learn:
1. Fundamentals of fracture mechanics and Fatigue Crack Growth:
2. Finite Element Method (FEM) and eXtended Finite Element Method (XFEM)
- Core principles of FEM and how they apply to crack propagation simulations.
- Coverage of XFEM, including enrichment functions, and level-set methods.
- How to model cracks without remeshing the mesh during propagation and how XFEM handles discontinuities.
3. Fatigue Crack Propagation Regimes:
- Understanding the relationship between crack size and cycles, including factors like stress ratio effects.
- Detailed exploration of crack growth laws, including Paris Law, Walker Law, and NASGRO formulations.
- Methods for life prediction, failure criteria, and assessing the factor of safety in fatigue analysis.
4. Model Creation in ABAQUS:
- Step-by-step guidance on part creation and material definition, including damage models for traction separation.
- Implementation of direct cyclic and low cycle fatigue steps, focusing on Fourier representations, and convergence criteria.
- Special interaction properties like pre-crack definitions and Paris Law implementation for fatigue analysis.
5. Results Interpretation and Post-Processing:
- Visualizing crack propagation patterns across different cycles.
- Generating and analyzing key outputs such as crack length vs. cycle graphs and fatigue crack growth rates (da/dN vs. ΔK).
6. Three different case studies.
Course Features:
- Detailed theoretical background paired with practical modeling exercises in ABAQUS.
- Real-world case studies and examples, including complex geometries.
- Guidance on setting up simulations for brittle materials using LEFM principles.
Who Should Enroll:
This course is designed for engineers, researchers, and under graduate or graduate students who wanted to get a very good understanding of finite element analysis and wish to expand their knowledge in the field of fracture and fatigue analysis using ABAQUS. It is particularly beneficial for those interested in crack growth modeling and the application of advanced methods like XFEM and direct cyclic analysis in practical engineering scenarios.
By the end of the course, participants will be able to simulate, analyze, and interpret fatigue crack growth in various loading conditions, providing them with a competitive edge in the field of structural analysis and design.