Introduction to Air Blast Analysis of CFRP-PET Foam Composite Panels

1. Background and Importance

Composite sandwich structures, typically comprising Carbon Fiber Reinforced Polymer (CFRP) face sheets and a lightweight core such as Polyethylene Terephthalate (PET) foam, are widely used in aerospace, automotive, and defense industries due to their high stiffness-to-weight ratio, excellent energy absorption, and tailorable mechanical properties. These panels are increasingly subjected to extreme dynamic loading environments, such as blast waves resulting from explosions or air blasts.

Understanding the response of such structures under air blast loading is critical for:

• Safety and survivability design

• Lightweight armor systems

• Blast-resistant vehicles

• Building façade protection

2. Composite Panel Configuration

A typical CFRP-PET foam sandwich panel consists of:

• CFRP Face Sheets: Provide the majority of the panel’s in-plane stiffness and strength, resist tensile and compressive loads, and protect the core.

• PET Foam Core: Provides shear stiffness, thermal insulation, and energy absorption under impact or blast loads. The foam’s compressibility plays a significant role in dissipating blast energy.

3. Air Blast Loading

Air blast loading results from rapid energy release in an explosive event, creating a high-pressure shock wave. The blast wave interaction with the panel is characterized by:

• Positive overpressure peak

• Rapid pressure rise time

• Decay of pressure over time

• Impulse loading effect

For air blast simulations, the Friedlander equation or blast wave models based on CONWEP data are commonly used to define the pressure-time profile acting on the panel surface.

4. Analysis Approach

Air blast analysis of composite sandwich panels generally involves numerical simulation, such as finite element modeling (FEM), due to the complexity of interactions:

• Material models:

  • CFRP: Orthotropic elastic-plastic damage models or progressive failure models

  • PET Foam: Crushable foam models with strain rate sensitivity

• Structural response modes:

  • Global bending and deflection

  • Local face sheet delamination or cracking

  • Core shear and compression failure

  • Debonding between faces and core

5. Applications and Future Work

Research into the  air blast response of CFRP-PET panels informs:

• Optimized structural design for blast mitigation

• Hybrid material configurations (e.g., combining PET with other foams or honeycombs)

• Design guidelines for protective structures in defense and civil infrastructure