Concrete Pump Truck Pumping Hydraulic System Failure Simulation Study

Concrete pump truck is one of the most highly-technical, the most difficult to maintain and the most expensive equipment. It is widely used in construction of roads, bridges and buildings because of their flexibility, high efficiency, high automation and good mobility. However, because of complex structure, high flow, high reversing frequency and severe impact suffered by hydraulic pump system of concrete pump truck, fault often occurs during working time of pump system. And it is often hardly to locate the bug and determine the reason for the fault through analysis of external phenomenon of fault. Because hydraulic pump and hydraulic valve of hydraulic system are often very expensive, therefore, it is costly and time-consuming to obtain data samples for neural network training through experiment. Besides, some fault samples are difficult to obtain through experiment. Therefore, it is meaningful to analyze hydraulic system and obtain fault samples through development of virtual simulation model of hydraulic system.The paper first briefly introduced developing history of the concrete pump truck and its compositions, operating principle and developing trend. The fundamental loop, operating principle and operating process of the pump hydraulic system were analyzed in detail. Then dynamic simulating process of the basic hydraulic elements was derived, functions and characteristics of software AMESim was introduced, operating principle, characteristics and mathematical model of the primary elements were especially analyzed to establish models of overlap-type relief valve, two-way cartridge valve and hydraulic operated directional valve et al., according to which the whole hydraulic system was simulated and tested via optimizing the model by comparing sample data and experimental measurements. Subsequently, fault samples in recent two years were collected and arranged to determine and clarified statistically locations and reasons of the frequent faults. Several typical faults were brought in the model to provide enough training samples for the subsequent diagnosis model by analyzing effects of different faults on system dynamic characteristics. Fault tree of the typical faults were achieved from logic analysis to provide theoretical guidance for fault diagnosing through simulations or experiments. Finally, pressure of key nodes in the pump hydraulic system and vibration signals of the hydraulic pump were measured experimentally. Tests and analysis of various faults such as main cylinder leakage, swash-plate wear of hydraulic pump, port plate wear, and bearing damage and so on were implemented via physical simulation method.Based on research, it is proved that numerical simulation is an effective method for analysis of dynamic characteristics of hydraulic pump system. Through development of simulation model by AMESim and field experiment, the problem of high cost and lengthy period to conduct experiment was solved and an effective method was proposed to collect fault samples.