High-frequency fiber Bragg gating accelerometer and strain sensor-based blast test on a concrete slab

Area of Science:

• Materials Science
• Mechanical Engineering
• Structural Engineering

Background:

• Blast testing is crucial for assessing explosive performance and structural safety.
• Electrical sensors in blast tests suffer from signal scattering due to long wires and electromagnetic interference.
• There is a need for robust and reliable sensors for accurate blast wave measurement.

Purpose of the Study:

• To design and manufacture a high-frequency fiber Bragg grating (FBG) accelerometer for blast testing.
• To measure acceleration and stress wave propagation on a blast-loaded concrete slab.
• To validate the performance of FBG sensors in dynamic blast environments.

Main Methods:

• A double-hinge high-frequency fiber Bragg grating (FBG) accelerometer was designed and fabricated.
• The sensor's resonance frequency (3400 Hz) and sensitivity (6.26 pm/g) were characterized.
• Seven controlled blasts (50 kg TNT equivalent) were conducted, measuring stress waves at 4m, 6m, and 8m.
• Numerical simulations were performed and compared with experimental data.

Main Results:

• Peak accelerations of 396.21 g, 123.57 g, and 38.88 g were recorded at different distances.
• The stress wave propagation velocity was determined to be approximately 2500 m/s.
• Experimental results aligned with empirical formulas, confirming sensor reliability.

Conclusions:

• The developed FBG accelerometer effectively measures acceleration and stress waves in blast tests.
• Fiber optical sensors offer a reliable alternative to electrical sensors, mitigating interference issues.
• The study highlights the practical applicability of FBG sensors for blast testing and structural health monitoring.