Underwater Aircraft Strain Testing at Harbin Lab

In February 2024, Peking University conducted an underwater strain test on an aircraft structure at a laboratory in Harbin, utilizing the RE-846U ruggedized dynamic data acquisition system combined with triaxial strain rosettes.

A total of 12 underwater strain rosettes were installed on the aircraft's surface and flaps to measure strain under varying flow conditions (0.4–2.4 m/s water velocity). The test aimed to analyze structural deformation and stress distribution under hydrodynamic loads.

Key Test Details

1. Equipment & Setup

• RE-846U Data Acquisition System: High-speed, waterproof, and shock-resistant, suitable for harsh underwater environments.

• Triaxial Strain Rosettes: Provided multi-directional strain measurements (ε_x, ε_y, ε_xy) to assess complex stress states.

• Hydrodynamic Simulation: Controlled water flow velocity to replicate real-world operational conditions.

2. Test Procedure

• Sensor Placement: Strain rosettes were bonded to critical areas (wing roots, control surfaces) to capture bending, torsion, and hydrodynamic pressure effects.

• Data Acquisition: Synchronized strain and flow velocity measurements across all 12 channels.

• Load Cases: Incremental flow speeds (0.4–2.4 m/s) to evaluate strain response under increasing hydrodynamic forces.

3. Analysis & Results

• Strain Distribution Mapping: Identified high-stress zones (e.g., flap hinges, leading edges).

• Flow-Strain Correlation: Determined how varying flow velocities affect structural deformation.

• Validation: Compared experimental data with computational fluid dynamics (CFD) and finite element analysis (FEA) models for accuracy verification.

Significance

•     Structural Integrity Assessment: Ensured the aircraft’s hydrodynamic load-bearing capability.

•     Design Optimization: Data supported material selection and reinforcement strategies for underwater applications.

•     Cross-Institutional Collaboration: Demonstrated Peking University’s advanced testing capabilities in partnership with Harbin Engineering University.

Conclusion
The underwater strain test successfully characterized the aircraft’s structural response under varying hydrodynamic loads, confirming design integrity and highlighting areas for reinforcement. The collected data not only validated computational models but also provided actionable insights for optimizing materials and structural layouts in future underwater operations.

For detailed strain-time histories or CFD-FEA correlation reports, please contact the research team.