A failure propagation model for a city pipeline network was developed to simulate the scope of the failure propagation to provide a scientific basis for accident prevention.

To find the failure propagation mechanism from the inherent topological structure of the complex electromechanical system,the topological structure statistical properties of the system were analyzed with small world net theory,and a failure propagation model based on the small world clustering was proposed.

In order to solve the problem of complexity and uncertainty of fault propagation and analysis in complex system, a new model for fault propagation and fault diagnosis in complex system-Fuzzy Probability Petri Nets System (FPPNS) was constructed.

Based on the structure of system devices and fault propagation nature between the subdevices.

A k-steps fault pervasion and localization algorithm is put forward,which fractionalizes the fault directional graph and finds the optimal pervasion route or the most suspicion nodes with the fault propagation probability matrix.

It is more convenient for analyzing fault transfer.

Besides,the paper builds the model of faults of multi-axis machine tool with petri net,and analyzes the mechanism of fault transfer,and has proved the effectiveness of this algorithm.

A kind of integrated qualitative and quantitative modelbased collaborative fault diagnosis method has been applied on the brake-by-wire system of locomotion engineering machine,and fault propagation graph s Hierarchical generation strategy has been detailed with corresponding model diagnoses observer.