Strain Testing Report for Next-Generation Rocket Thruster
Project: Strain Testing Report for Next-Generation Rocket Thruster
June 2023 · A Leading Aerospace Research Institute
Conducted dynamic strain testing on a new liquid rocket engine thruster during ignition to:
1. Verify structural margin of the thrust chamber base under high-temperature/pressure gas impact
2. Obtain strain concentration factors in weld zones
3. Establish strain-thrust correlation models for design optimization
Test System Configuration
| Item | Specifications/Method |
|---|---|
| Equipment | - DU-8324U Portable Dynamic Test System (16 ch/unit × 3 units)
- SE-series Static Strain Analysis System (24 ch/unit × 1 unit) |
| Sensor Layout | - 42 high-temperature strain gauges (Type K thermocouple-integrated, 1200°C rated)
- Coverage: • Thrust flange (12 pts) • Nozzle convergence section (18 pts) • Reinforcing ring welds (12 pts) |
| Synchronization | IEEE 1588 Precision Clock Protocol (inter-system deviation <1μs) |
| Sampling | - Dynamic system: 50 kHz (16-bit)
- Static system: 1 kHz (24-bit) |
Key Technological Breakthroughs
Extreme Environment Measurement
Applied plasma-sprayed insulation layers to enable strain gauge installation (maintained >15MPa bond strength at >800°C)
Developed combustion flow compensation algorithm to eliminate high-frequency vibration noise
Multi-Physics Coupling Analysis
Synchronized data fusion:
Strain
Thrust profile (from test stand)
Chamber pressure (Pc sensors)
Fail-Safe Design
Implemented redundant dual-circuit wiring for continuous data acquisition during single-point failures
Key Test Data
Ignition Phase (T+0~2s)
Peak strain zone: 30mm upstream of nozzle throat (ε<sub>max</sub>=2175με)
Dynamic characteristics:
• Dominant frequency: 284Hz (4.3% deviation from FEA)
• Damping ratio: 0.032
Steady-State Operation (T+2~58s)
Detected abnormal strain fluctuations (Δε≈400με) at Weld Zone 3, later identified as localized material creep
Engineering Impact
Design Optimization: Adjusted stiffener layout to reduce peak strain by 22%
Process Improvement: Optimized welding parameters, cutting weld strain dispersion from ±18% to ±7%
Standardization: Established QJXXXX-2023 rocket engine strain test protocol
Terminology
Type K strain gauges: High-temperature sensors measuring strain + temperature simultaneously
FEA: Finite Element Analysis
με: Microstrain (1με=10<sup>-6</sup> mm/mm)
This test achieved China's first millisecond-level full-scale strain field reconstruction for rocket engines, with applied outcomes in the Long March-X upgraded engine development.
