What is the most challenging aspect you think about when dealing with fracture modelling, especially when the material is brittle like concrete, masonry, or rock? A fracture modelling, right? And the solution is element deletion techniques in Abaqus. It simulates progressive material failure by removing damaged elements during analysis.
This article covers the mechanics of element deletion in Abaqus, its integration with the Abaqus Concrete Damage Plasticity (CDP) model, applications in masonry wall studies, & why it is increasingly featured in the structural analysis courses.
What Is Element Deletion In Abaqus
It is a numerical modelling technique that removes mesh elements once they meet the predefined failure criteria. So instead of continuing to carry out the unrealistic stresses after cracking, these elements are deleted from the computational domain. It allows cracks to propagate naturally.
What are the Deletion Criteria
The typical deletion criteria in structural engineering Abaqus tutorials include:
- Strain-based criteria: the elements are removed when the tensile or compressive strain exceeds the threshold. It is useful for simulating progressive cracking in beams & slabs.
- Stress-based criteria: the elements are deleted when the maximum principal stress exceeds the material strength. It modelled localised damage in an impact or blast scenario.
- Energy-based criteria: the elements are deleted once the fracture energy (Gf) is dissipated.
Mostly used to analyse collapse mechanisms in brittle materials.
Abaqus CDP & Its Role in Fracture Modelling
The Abaqus Concrete Damage Plasticity (CDP) model is a constitutive law. It is widely used for simulating nonlinear behaviour in concrete. It explains both tensile cracking & compressive crushing while enabling realistic fracture simulations.
Salient features of CDP are:
- Tensile softening laws: to capture crack initiation & growth.
- Comprehensive damage functions: simulate spalling & crushing.
- Stiffness degradation rule: reduces material stiffness after cracking.
- Non-associated plastic flow: ensures realistic dilatancy.
When coupled with element deletion, CDP provides a robust framework for simulating complete structural failure. Research has found that combining CDP with deletion can predict crack paths with an improved accuracy of 20% to 30% compared to the model without deletion.
Application to Masonry Walls
Masonry walls are brittle due to the limited tensile capacity of the bricks & mortar joints. Simulation of their fracture response is important for the seismic & blast-resistant design.
In an Abaqus tutorial masonry walls study, element deletion was used to model:
- Diagonal shear cracking under lateral loads.
- Vertical cracking due to settlement or compression.
- Out-of-plane collapse during the seismic shaking.
Engineers integrate CDP with cohesive modelling (CZM) to improve accuracy. It allows the simulation of mortar-brick interface debonding. A study shows that element deletion predicts the progressive failure pattern closely, matching experimental results, especially for low-rise unreinforced masonry walls.
Advantages Of Element Deletion in Complex Fracture Problems
- Captures natural crack propagation. There is no need for predefined crack paths.
- Simulates progressive collapse. It’s essential for safety analysis in bridges, towers & masonry.
- Applicable across materials like concrete, masonry, metals, composites & rocks.
- Reduces the mesh bias when combined with fracture energy regularisation.
Practical Setup in Abaqus
A simplified workflow setup for the engineers learning through the structural analysis courses is:
1. Define Material Properties: Input elastic, compressive & tensile strengths along with the fracture energy.
2. Activate Abaqus CDP: It specifies the damage initiation (stress/strain) & evolution (energy)
3. Enable Element Deletion: Set element removal criteria in the damage evolution model
4. Mesh Sensitivity Check: Refine the mesh near stress concentration zones to minimise dependency.
5. Run Simulation & Validate: compare crack patterns with experimental or field data.
This workflow is covered in the structural engineering Abaqus tutorials. It gives learners a practical understanding of the real-world modelling challenges.
Why Learn This in Structural Analysis Courses
Advanced fracture modelling is included in many structural analysis courses. Because modern design codes demand performance-based analysis rather than just elastic designs.
The key learning outcomes are:
- Mastering Abaqus CDP for concrete fracture.
- Applying element deletion in beams, slabs & masonry structures.
- Understanding progressive failure analysis for collapse predictions. Developing practical skills for consulting, research & advanced designing.
By practising it with the tutorials, whether it’s structural engineering, an Abaqus tutorial on beams, or an Abaqus tutorial on a masonry wall case study. It helps engineers to gain a competitive edge in both academic & industrial roles.
Conclusion
Element deletion techniques in Abaqus represent a powerful approach to simulating complex fracture modelling in concrete & masonry structures. When integrated with the Abaqus CDP model, they allow engineers to capture crack initiation, propagation & ultimate collapse with remarkable accuracy.
Mastering element deletion is a key skill for engineers working in the safety-critical fields. This technique prepares professionals to tackle fracture & failure challenges with confidence.
Ready to build hands-on expertise in Abaqus fracture modelling? Join our Abaqus Structural Analysis CDP Training at Pigso Learning and gain practical skills through expert-led tutorials and real-world projects.
Contact us today to get started!
