Service Life Prediction Method for Concrete and Prestressed Concrete Bridges under Chloride-Aggressive Environments

2018 ◽  
Vol 47 (3) ◽  
pp. 20180035 ◽  
Author(s):  
Ying Huang ◽  
Jun Wei ◽  
Rongzhen Dong
Keyword(s):  
Service Life ◽  
Prestressed Concrete ◽  
Life Prediction ◽  
Prediction Method ◽  
Concrete Bridges ◽  
Service Life Prediction ◽  
Prestressed Concrete Bridges

scholarly journals Research on the Dynamic Erosion Wear Characteristics of a Nozzle Flapper Pressure Servo Valve Used in Aircraft Brake System

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yuanbo Chu ◽  
Zhaohui Yuan ◽  
Wenchao Chang
Keyword(s):  
Service Life ◽  
Life Prediction ◽  
Wear Behavior ◽  
Prediction Method ◽  
Service Life Prediction ◽  
Dynamics Simulation ◽  
Brake System ◽  
Erosion Wear ◽  
Wear Characteristics ◽  
Servo Valve

The nozzle flapper pressure servo valve is a kind of high-precision hydraulic component that can be widely used in the aircraft brake system. In actual service, the dynamic erosion wear behavior will occur at the pilot stage because of the gradual contamination of oil and the variable distance between nozzle and flapper. For this purpose, the paper proposes a dynamic erosion wear characteristics analysis and service life prediction method in which firstly the structural feature and working principle of the nozzle flapper pressure valve are analyzed using the brake cavity as the load blind cavity. Secondly, the dynamics simulation model and the performance experiment system of the pressure valve are separately constructed, and then the validation of the constructed model is conducted by contrasting the results between simulation and experiment. Finally, the mathematical models of the degradation process induced by the dynamic erosion wear are established, and then the dynamic erosion wear characteristics under dynamic structural distance and contamination conditions are analyzed, which are combined with the failure threshold value determined by the dynamics simulation to finish the service life prediction of the nozzle flapper pressure servo valve.

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