How to model cracking phenomena in Ansys Mechanical (Structural)

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 Cracking phenomena are the processes of initiation, propagation, and failure of cracks in materials or structures due to various factors, such as stress, temperature, fatigue, corrosion, etc. Cracking phenomena can affect the performance, safety, and reliability of engineering systems and components. Therefore, it is important to be able to model and analyze cracking phenomena using simulation tools such as Ansys Mechanical.

Ansys Mechanical is a software product that provides finite element analysis (FEA) solutions for modeling structural mechanics problems. Ansys Mechanical can handle linear and nonlinear, static and dynamic, and thermal and coupled physics problems. Ansys Mechanical can also simulate various types of materials, such as metals, plastics, composites, and biomaterials.

To model cracking phenomena in Ansys Mechanical, you need to use some special features and capabilities that are available in the software. Some of these features are:

  • Fracture: This is a feature that allows you to define and apply fracture criteria to your model based on stress intensity factors (SIFs), energy release rates (ERRs), or J-integrals. Fracture can be used to simulate linear elastic fracture mechanics (LEFM) or nonlinear fracture mechanics (NLFM) problems. Fracture can also be used to model different types of cracks, such as pre-meshed cracks, arbitrary cracks, or semi-elliptical cracks.
  • SMART Crack Growth: This is a feature that allows you to simulate the growth and propagation of cracks in your model using separating morphing adaptive remeshing technology (SMART). SMART Crack Growth can handle 2D or 3D crack problems with complex geometries and loading conditions. SMART Crack Growth can also account for mixed-mode loading, contact effects, plasticity effects, and thermal effects.
  • XFEM: This is a feature that allows you to model cracks without explicitly meshing them using the extended finite element method (XFEM). XFEM can enrich the standard finite element approximation with additional functions that capture the discontinuity and singularity of the crack. XFEM can be used to model stationary or propagating cracks with various criteria, such as maximum hoop stress, maximum circumferential stress, or Paris law.

These are some of the features that you can use to model cracking phenomena in Ansys Mechanical. You can also use other features and tools that are integrated with Ansys Mechanical, such as Ansys Workbench, Ansys Fluent, Ansys APDL, etc., to create and manage your simulation projects.

If you want to learn more about how to use these features and tools to model cracking phenomena in Ansys Mechanical, you can check out some of the sources that I found using Bing:

  • Ansys Multiphysics Simulation for Crack Propagation Analysis: This is a webinar that demonstrates a multiphysics simulation for crack propagation analysis using Ansys Workbench, Ansys Mechanical, and Ansys Fluent. You will learn how to use SMART Crack Growth to analyze crack growth due to thermo-mechanical fatigue (TMF).
  • Get Cracking with ANSYS Workbench 19.2: This is an article that revisits Ansys Workbench to carry out a series of fracture mechanics analyses using SMART Crack Growth. You will learn how to create and edit joints in Ansys Workbench, how to specify the degrees of freedom, stiffness, damping, and friction properties for the joints, how to apply loads and moments to the joints, and how to post-process the results of the joint analysis.
  • how to create a crack on a 3D surface body in ANSYS workbench?: This is a forum thread that discusses how to create a crack on a 3D surface body in Ansys Workbench using Pre-Meshed Crack option. You will learn how to select the crack edge, top surface, bottom surface, and coordinate system for the crack definition.
If you are looking for some material models that can handle the cracking phenomena in Ansys Mechanical, you are in luck! I have found some amazing models that can do just that. Let me tell you more about them:

- **Anisotropic Plasticity using Hill Potential**: This model is perfect for metals that have different strengths in different directions, like a sheet of paper. It can show you how the metal gets damaged and breaks due to bending or stretching.
- **Cast Iron**: This model is great for cast iron materials, which are very strong when you squeeze them, but very weak when you pull them apart. It can show you how the cast iron cracks and shatters under tension, and how it depends on the temperature, the speed of loading, and the shape of the grains.
- **Microplane**: This model is awesome for concrete, which is a mixture of rocks, cement, and water. It can show you how the concrete cracks and softens when you pull it, and how it crushes and expands when you push it.
- **Shape Memory Alloys**: This model is amazing for shape memory alloys, which are metals that can change their shape when you heat them or stress them. It can show you how the shape memory alloys transform from one phase to another, and how they recover their original shape after being deformed.

These are some of the material models that can help you with your cracking phenomena in Ansys Mechanical. You can learn more about them by clicking on the links I have provided. I hope you find this interesting and helpful. 

The sources for the text are:

- [Understand a Design’s Breaking Point with Simple Crack Propagation Simulations](^1^): This is a blog post from Ansys that explains how to use the unstructured mesh method (UMM) and the separating morphing and adaptive remeshing technology (SMART) to simulate crack propagation in Ansys Mechanical. It also compares the results of UMM with the traditional hexahedral mesh method.
- [Material property data for engineering materials](^2^): This is a PDF document from Ansys that provides some material property data for common engineering materials, such as density, thermal conductivity, elastic modulus, etc. It also includes some physical constants, such as the gas constant, the Boltzmann constant, etc.
- [Simulate Brittle Cracking](^3^): This is a forum post from Ansys Learning Forum that discusses how to simulate the cracking of a nutshell in Ansys static structural. It also provides some screenshots of the model and the boundary conditions.

(1) Understand a Design’s Breaking Point with Simple Crack ... - Ansys. https://www.ansys.com/blog/breaking-point-crack-propagation-strength-of-materials.
(2) Material property data for engineering materials - Ansys. https://www.ansys.com/content/dam/amp/2021/august/webpage-requests/education-resources-dam-upload-batch-2/material-property-data-for-eng-materials-BOKENGEN21.pdf.
(3) Simulate Brittle Cracking - Ansys Learning Forum. https://forum.ansys.com/forums/topic/simulate-brittle-cracking/.

I hope this helps you understand how to model cracking phenomena in Ansys Mechanical. If you have any questions or feedback, please let me know. 😊



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