Crack Setup Using MAT_ADD_EROSION in ANSYS LS-DYNA

[Yalew Tebeje]

Dear Ls-dyna community,

I hope you all are pretty fine. I am reaching out to seek your expertise in ANSYS LS-DYNA, specifically regarding the modeling of crack setups using the MAT_ADD_EROSION material model during the blasting of hard rock.

I am currently working on a project that involves simulating crack propagation in hard rock under blast loading conditions. I aim to use the MAT_ADD_EROSION model in LS-DYNA to capture material failure and erosion effectively. However, I am facing challenges in setting up the model correctly, particularly in defining the erosion criteria and ensuring accurate crack propagation behavior.

Could you kindly provide guidance or share best practices for the following:

·        Properly configuring the MAT_ADD_EROSION parameters for hard rock blasting simulations.

·        Defining appropriate failure criteria to model crack initiation and propagation.

·        Any specific meshing techniques or element types recommended for capturing crack behavior accurately.

·        Common pitfalls to avoid when setting up such simulations in LS-DYNA.

If you have any example input files, case studies, or references related to similar applications, I would greatly appreciate it if you could share them. Additionally, I’d be happy to discuss my project in more detail or provide specific information about my setup if that would help in tailoring your advice.

Thank you for your time and consideration. I look forward to your insights and any recommendations you might have.

Regards,

Yalew Tebeje

[Ram Gopisetti]

Hi, 

I initially recommended that you develop a thorough understanding of each parameter within MAT_ADD_EROSION, including what each one represents and how it contributes to modeling failure criteria. Given the brittle nature of the material in question, it is essential to investigate how brittle failure mechanisms are captured using the selective parameters provided within MAT_ADD_EROSION, especially when used in conjunction with parent materials such as JHC, MAT_193, or MAT_173, among others.

In most cases, brittle failure is characterized by strain-based criteria and associated parameters. Therefore, focus should be placed on how strain and its thresholds are defined and utilized within this context to simulate brittle material failure accurately.

Cheers, Ram 

[julmeshreeya2210]

Dear Sir/Madam,

I hope you are doing well.

I am currently working on a Notched Semicircle Bend test simulation project in ANSYS LS-DYNA and would greatly appreciate your guidance regarding crack propagation modeling.

In my model, I am using MAT_ELASTIC along with MAT_COHESIVE_MIXED_MODE and MAT_ADD_EROSION to simulate crack initiation and material failure under three point loading. However, despite implementing these material models, the crack is not propagating as expected during the analysis.

I suspect the issue may be related to the erosion parameters, cohesive zone calibration, mesh dependency, or contact/timestep settings. Since I am relatively new to this type of coupled damage modeling, I would be very grateful for any suggestions or best practices you could share.

Specifically, I would like to seek guidance on:.
Appropriate failure criteria for realistic crack initiation and propagation.
Proper setup of MAT_COHESIVE_MIXED_MODE parameters.
Recommended element types and mesh strategies for crack tracking.
Possible reasons why cohesive cracks fail to propagate .
Common mistakes or numerical stability issues to avoid in LS-DYNA.

Thank you very much for your time and support. I look forward to learning from your experience and insights.

Best regards,

Shreeya Julme

[Rob]

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