Predicting crack paths without manual remeshing

Fatigue crack growth simulations are traditionally iterative and labor intensive. Each increment in crack length requires geometry updates, remeshing, state mapping, and manual intervention. This procedure slows down development, especially when evaluating multiple geometrical variations or load cases.

For linear elastic fracture mechanics problems under cyclic loading, engineers need: 

1. Accurate stress intensity factor evaluation

2. Robust crack path prediction 

3. Automated mesh update near the crack front

4. Minimal analyst intervention
   

The 2026 Abaqus Standard capability for fatigue crack growth with tetrahedral element based adaptive remeshing addresses exactly this bottleneck.

Combining Paris law with contour integral fracture mechanics

The method integrates classical fracture mechanics with automatic remeshing.

Crack growth rate is computed using the Paris Law:

[ da/dN = C(\ΔK)^m ]

Where ΔK is obtained using the contour integral method at the crack front.

After each crack increment:

1. The crack front is updated

2. A new tetrahedral mesh is automatically generated 

3. The mesh conforms to the updated crack geometry

4. The next fatigue increment is solved. 

   
   

Because the method is limited to linear elastic fatigue crack growth, no state mapping is required between increments. This significantly simplifies the workflow.

Modified compact tension benchmark with curved crack path

To demonstrate the capability, a modified compact tension specimen based on Miranda et al. (2003) is analyzed. An additional hole is introduced to curve the crack propagation path.

Figure 1: A modified compact tension specimen (dimensions in mm) subjected to cyclic loading

The geometry of the described specimen includes:

1. A standard compact tension specimen with a primary crack notch

2. An additional hole of 7 mm diameter placed to the side of the crack path 

3. Cyclic tensile loading applied at stress ratio R = 0.1

4. Two configurations, CT1 and CT2, with the hole positioned at slightly different vertical distances from the notch root

The relative hole position determines whether the crack deflects away from the hole or propagates toward it.

CT1 case: Crack deflection away from the hole

In the CT1 configuration, the crack initially propagates toward the hole. As it approaches, the stress intensity redistribution causes the crack to deflect away.

Figure 2: A comparison of the crack path obtained based on finite element prediction with experimental measurement for the modified compact tension specimen CT1

The numerical prediction aligns closely with the experimental trajectory.

To better visualize the crack evolution:  

Figure 3: Animation of how the crack proagates for the modified compact tension specimen CT1.

Figure 4: Animation of a local view of how the crack propagates for the modified compact tension specimen CT1.

CT2 case: Crack attraction and penetration into the hole

In the CT2 configuration, the hole position causes a different stress redistribution. The crack propagates toward the hole and ultimately merges into it.

Figure 5: A comparison of the crack path obtained based on finite element prediction with the experimental measurement for the modified compact tension specimen CT2

The simulation reproduces the experimentally observed attraction effect.

For visualization:

Figure 6: Animation of how the crack propagates for the modified compact tension specimen CT2

Figure 7: Animation of a local view of how the crack propagates for the modified compact tension specimen CT2.

How automated crack growth improves engineering workflows

This capability eliminates the need for:

1. Manual crack front advancement 

2. Rebuilding meshes between increments

3. Custom scripting for geometry updates

4. Repeated analyst driven preprocessing

It enables:

1. Fully automated fatigue crack growth studies

2. Rapid evaluation of geometric variations

3. Early stage durability validation

4. More reliable crack path prediction in complex geometries

For industries such as aerospace, offshore, heavy machinery, and energy, this reduces simulation turnaround time and increases robustness of fracture assessment workflows.

Implementing adaptive fatigue crack growth in practice

To use this capability effectively:

1. Define a linear elastic material model

2. Use contour integral evaluation for stress intensity factors

3. Activate tetrahedral adaptive remeshing 

4. Define fatigue parameters via Paris law

5. Validate against known benchmark geometries

Correct setup of fracture criteria and remeshing controls is essential for stable convergence.

Accelerating fracture simulations with the right setup 

Adaptive fatigue crack growth requires more than activating a feature. It requires correct fracture setup, mesh control strategy, validation methodology, and alignment with your durability process.

4RealSim supplies SIMULIA Abaqus licenses and supports companies in implementing automated fracture workflows, from initial benchmark replication to integration into production durability programs.

If you are evaluating Abaqus for fatigue crack growth or want to replace manual crack propagation procedures with a robust automated workflow, contact 4RealSim at marketing@4realsim.com. or fill in the contact form to discuss software acquisition and technical implementation support.

References

Miranda,  A., M. Meggiolaro, J. Castro, L. Martha, and T. Bittencourt, “Fatigue Life and Crack Path Predictions in Generic 2D Structural Components,” Engineering Fracture Mechanics, vol. 70, 2003.

This article is based on publicly available information from Dassault Systèmes SIMULIA.