Sealing performance and structural optimization of hose clamps: simulation study from contact mechanics to multi field coupling

Keywords: hose clamp sealing, contact mechanics, multi field coupling, structural optimization

abstract

The sealing failure of clamps is one of the main causes of pipeline leakage. This article takes a certain type of aviation hydraulic pipeline clamp as an example to analyze the core technology for improving its sealing performance.

2.1 Sealing defects of traditional clamps

Unreasonable geometric parameters with teeth: excessive tooth profile angle (>60 °) can cause local crushing of the hose, while insufficient tooth profile (<30 °) can lead to slipping and leakage.

The reliability of the locking mechanism is poor: when manually tightened, the torque fluctuates greatly (± 25%), making it difficult to ensure consistent sealing pressure (such as the target value of 10N · m, actual value of 7.5-12.5N · m).

2.2 Contact Mechanics and Tooth Shape Optimization

Fractal geometry modeling: Using Mandelbrot fractal theory to describe the contact interface between toothed and flexible hoses, it was found that when the fractal dimension D=1.3, the contact area is the largest and the leakage risk is the lowest.

Biomimetic tooth design: Drawing on the microstructure of shark skin, the clamp tooth shape is changed to a "trapezoidal+micro convex" composite structure, increasing the contact area by 50% and the friction coefficient from 0.25 to 0.4.

2.3 Multi field coupling simulation and experiment

Thermal mechanical chemical coupling analysis: Using COMSOL Multiphysics to simulate the deformation of clamps under high temperature of 120 ℃, pressure of 5MPa, and aviation kerosene medium, optimize the toothed height (from 1.5mm to 1.2mm) to reduce hose creep.

Leakage rate test: Helium mass spectrometer leak detector (accuracy 1 × 10 ⁻12 Pa · m 3/s) was used for verification, and the optimized clamp leakage rate was reduced from 0.05mL/min to 0.001mL/min.

2.4 Standardized Testing and Certification

MIL-STD-810G standard: Simulate cold and hot cycles from -55 ℃ to 125 ℃ (500 times), with a clamp torque attenuation rate of<8%, and the sealing is checked by helium gas leak detection (leakage rate<1 × 10 ⁻⁹ Pa · m 3/s).

NASA-STD-6001 certification: Passed 100000 dynamic fatigue tests (frequency 10Hz, amplitude ± 3mm), with no broken or loose clamps.

conclusion

The optimization of sealing performance requires the combination of contact mechanics and multi field coupling simulation. Through biomimetic tooth profile and multi parameter collaborative design, the sealing reliability and durability of the clamp can be significantly improved.