Introduction to Glass Analysis and Simulation Using the Johnson-Holmquist Model in Abaqus

Glass is a brittle material widely used in defense, automotive, civil, and aerospace engineering due to its transparency, hardness, and relatively low density. However, its failure behavior under dynamic loading, such as high-velocity impacts, differs significantly from metals or polymers. Unlike ductile materials, glass exhibits sudden crack initiation, rapid propagation, and fragmentation. Accurately capturing this behavior in computational simulations requires constitutive models tailored for brittle materials.

One of the most widely used constitutive frameworks for brittle solids under high strain rates and pressures is the Johnson–Holmquist (JH) model, which exists in two primary forms: JH-1 and JH-2. Both were developed to describe the response of ceramics and glasses under conditions of impact, penetration, and blast loading.

In this package, during 10 different tutorials, all aspects of the glass modeling and simulation are investigated.

The Johnson-Holmquist (JH) Model

Key Features:

• Designed for brittle materials such as glass, ceramics, and concrete.
• Accounts for:
  • Elastic-plastic behavior at low stress.
  • Damage evolution leading to softening.
  • Strain rate effects (important for impact and blast scenarios).
  • Pressure dependence of strength (materials resist fracture more under confinement).
• Capable of predicting fragmentation and pulverization of glass.

Core Components of the Model:

1. Strength Model: Strength increases with pressure and strain rate.
2. Damage Model: Progressive damage accumulates based on plastic strain and fracture energy.
3. Equation of State (EOS): Describes the pressure-volume relationship, essential for capturing shock and compression effects in glass.

Implementation in Abaqus

In Abaqus/Explicit, brittle materials such as glass can be simulated using the Johnson–Holmquist Ceramic (JH-2) model, which is available through writing code in the input file to call the VUMAT, or the VUMAT user subroutine (not a native built-in model). This requires user coding or accessing third-party subroutines.

Applications

• Ballistic impact on transparent armor systems (glass/ceramic composites).
• Automotive safety (windshield fracture in a collision).
• Aerospace (bird-strike on canopies, space debris impacts).
• Civil engineering (glass façade blast resistance).

✅ In summary: The Johnson–Holmquist model provides a robust framework to simulate brittle fracture and fragmentation of glass in Abaqus. Since the JH model is not a built-in option, it requires writing code in input or a VUMAT implementation, parameter calibration, and careful meshing strategies. Properly applied, it enables realistic prediction of glass behavior under extreme loading scenarios.