VUMAT for the JHB and JH-2 Ceramic Model in ABAQUS

The purpose of the Abaqus VUMAT JHB and JH-2 Ceramic Model tutorial course is to learn, how to use Johnson-Holmquist (JH-2) and Johnson, Holmquist, and Beissel (JHB) built-in material models to simulate the failure behavior of brittle materials like ceramics.

With the release of Abaqus/Explicit 6.10 and later, two constitutive models for ceramics and other brittle materials are included as built-in material VUMATs:

• Johnson, Holmquist, and Beissel (JHB)
• Johnson and Holmquist (JH-2)

These models can be used to simulate the behavior of materials under high strain rate loading conditions, such as impacts.

Implementing Johnson-Holmquist Damage Models for Brittle Ceramics in Abaqus

The JHB and JH-2 models are continuum damage mechanics models used to simulate the failure of brittle ceramic materials. They are implemented in a VUMAT (user material) subroutine for Abaqus simulations to model the nonlinear behavior and damage of ceramics.

The JHB and JH-2 models are best suited for modeling the failure of brittle ceramic materials with linear elastic behavior up to failure and little or no plasticity. The VUMAT JHB and JH-2 ceramic models implement the constitutive model in Abaqus by calculating stresses, evolving damage, updating stiffness, and passing results to Abaqus at each increment.

To implement Johnson-Holmquist damage models for brittle ceramics in Abaqus, we suggest two solutions:

1. Using the built-in material model in Abaqus
   You have three choices for this. The JH-1, JH-2, and JHB models. All three models can be used in Abaqus without the need to write a VUMAT subroutine by defining a series of parameters in the Abaqus input file (*.inp). But if you want to develop your own VUMAT JHB and JH-2 ceramic models, the second solution is for you.
2. Writing a VUMAT subroutine
   You do not need to write a subroutine! We have already done this for you. By preparing this package, you also receive a VUMAT subroutine Fortran file that includes the JH-2 ceramic model and you can easily use it with the linking of Abaqus software with Visual Studio and the Fortran compiler. Also, if you know a little more, you can develop your proposed model by making changes in the formulation of JH-2. In this way, you save a lot of coding and research time.

What you’ll learn

• What are the Johnson, Holmquist, and Beissel (JHB) And Johnson-Holmquist (JH-2) ceramic models?
• What are the VUMAT JHB and JH-2 ceramic models’ damage parameters?
• Where and for what materials, VUMAT JHB and JH-2 ceramic models can be used?
• How to define and use Abaqus VUMAT JHB and JH-2 ceramic models in Abaqus?
• What is Hugoniot elastic limit in VUMAT JHB and JH-2 ceramic models?
• Set up Abaqus CAE for built-in VUMAT JHB and JH-2 ceramic models subroutine
• Define the damage behavior of brittle materials in Abaqus
• Define field variables for the VUMAT JHB and JH-2 ceramic models in Abaqus
• How to determine the required VUMAT JHB and JH-2 ceramic models parameters from physical tests
• How to define the VUMAT JHB and JH-2 ceramic models in an Abaqus input file
• Run Abaqus with built-in VUMAT JHB and JH-2 ceramic models
• Perform single-element analysis with/without VUMAT subroutine
• Simulate high-velocity impact in Abaqus
• Visualize the damage/stress/displacement/strain results

Overview of VUMAT JHB and JH-2 Ceramic Model Course

1. Introduction to VUMAT JHB & JH-2 ceramic model
2. Abaqus VUMAT JHB & JH-2 ceramic model parameters
3. Modeling ceramic failure with the JHB and JH-2 continuum damage mechanics models
4. Implementing Johnson-Holmquist damage models for brittle ceramics in Abaqus
5. Examples & workshops
6. Additional modeling issues
7. Limitations