Research of Determining Low-Reliability Elements of Multiple-Flows Compressed Air Braking System Based on Goal-Oriented (GO) Methodology

The multi-flows pneumatic braking system is one of the modern braking systems equipped with truck vehicles which is a very complex system consisting of many elements connected in series or parallel. The reliability of the braking system has a significant influence on safety and the ability to manoeuvre. The study of identifying low-reliability elements in the brake system is of great significance to improve the efficiency of maintenance and repair. This article shows the research results that determine low-reliability elements of the multi-flows pneumatic brake system based on GO methodology, and allow to examine each element's reliability and the complex system. The reliability assessment model is built based on GO theory and statistics data collected at the used units about the frequency of damage, ability, and time to repair and restore the assemblies in the brake system. By using this model, the reliability of the assemblies and the whole system can be determined at any point in time relative to the actual operating time of the brake system. The article's research results can be applied for surveying other components’ reliability and complex systems such as steering or suspension systems.

Reliability analysis method for redundancy systems based on GO methodology and the universal generation function

In this study, Goal-Oriented (GO) methodology, as an important technique for reliability analysis, is used in multi-state redundancy systems. However, traditional GO operation is usually not sufficiently effective for such multi-state redundancy systems because of the complex computational problem. To solve this problem, an efficient UGF-based GO operation that combines the advantages of GO methodology and the universal generation function (UGF) is proposed. The algorithm can avoid the complex calculation process caused by the algorithm-based GO operation of traditional probability formulas, and can simplify the correction of the shared signal by regarding it as the system’s conditional probability. In addition, the further correction problem in which some dependent shared signals with a common failure are caused by other shared signals is also considered. Some application examples are presented to illustrate the proposed UGF-based GO methodology, as well as its effectiveness and practicability.

Application of GO methodology in reliability analysis of aircraft flap hydraulic system

ABSTRACTThe Goal-Oriented methodology (GO methodology) is an effective method for the reliability analysis of complex systems. It is especially suitable for the reliability analysis of multi-state complex systems containing the actual logistics, such as current, airflow and liquid flow. In order to solve the limitation that the GO methodology is not suitable for the reliability analysis of the system with feedback loop, the Boolean algebra idea is introduced to construct the Boolean operation formula of the feedback loop. In this paper, a certain type of civil aircraft flap hydraulic system with feedback loop is taken as the research object. According to the structural schematic diagram of the flap hydraulic system, the GO model of the flap hydraulic system is established. Next, the GO calculation is carried out to obtain the reliability of the flap hydraulic system. The comparison between the system reliability without feedback loop and that with feedback loop proves that the GO methodology with feedback loop is more accurate. The reliability of the system is analyzed by using the fault tree analysis (FTA) method, and the GO methodology with feedback loop is compared with the FTA method to verify the availability and correctness of the GO methodology in the reliability analysis and safety evaluation of aircraft flap hydraulic system.