A viscoelastic-viscoplastic constitutive model for polymer bonded explosives under low impact loading

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Mechanics

Background:

• Existing constitutive models for explosives often neglect plastic effects under low impact loading.
• Viscoplastic work is crucial for understanding explosive ignition under impact.
• Polymer-bonded explosives (PBXs) require accurate modeling for dynamic mechanical behaviors.

Purpose of the Study:

• To develop and validate a novel viscoelastic-viscoplastic (VE-VP) model for PBXs under low impact loading.
• To incorporate both viscoelastic and viscoplastic components to capture complex material responses.
• To enhance the predictive accuracy of explosive behavior under dynamic conditions.

Main Methods:

• A generalized Maxwell model was employed for viscoelastic (VE) responses.
• A J2 rate-dependent model with isotropic hardening was developed for viscoplastic (VP) behavior.
• Coupled VE-VP algorithms were implemented in ABAQUS using a VUMAT subroutine.

Main Results:

• The proposed VE-VP model accurately predicts the response of PBX 9501 under low impact loading.
• Numerical simulations demonstrated the computational efficiency and accuracy of the developed algorithms.
• Model predictions showed reasonable agreement with experimental data.

Conclusions:

• The developed VE-VP model provides a more comprehensive description of PBX dynamic mechanical behaviors compared to existing models.
• The model's ability to capture plastic effects under low impact loading is a significant advancement.
• This research contributes to improved safety and design of energetic materials under impact scenarios.