Abstract:

Based on power-bond theory, a graph bond model of the hydraulic system was built, with the impactor function analyses of a water-powered piler. By using of the AMESim software, a simulation model of the impactor hydraulic system was developed. Setting the parameters, the motion curves of the impact pistol and valve were obtained by running the simulation model. The motion charateristics of the piston and valve were discovered by analyzing curves of the displacement, the velocity and the acceleration. Furthermore, the influences on its performance were studied by adjusting the parameters separately such as flowrate, relief valve pressure, pistol mass, the underlap length of front chamber and middle chamber etc. The results show that increase of flowrate can not improve the impact performance of water-powered pile drive if it meets the rated value of the hydraulic system; higher relief valve pressure can utilize the input engergy fully and improve its proformance obvisouly; increase of the pistol mass will lower its performance; extending the underlap length of the front chamber can improve its proformance; however, extending the underlap length of middle chamer will lower its proformance. It provides the theoretical basis for optimization and design of water-powered pile driver impactor.

Key words: water-powered pile driver, water-powered impactor, AMESim simulation, power-bond graph

摘要：

分析了水压式打桩机冲击器的工作机理，根据功率键合图理论构建了其液压系统的键合图模型。以AMESim软件为平台，搭建了水压冲击器液压系统的仿真模型，通过设置参数，对该模型进行仿真，得到了冲击活塞和阀芯的运动曲线，继而分析了活塞和阀芯的位移、速度、加速度随时间的变化规律。通过依次改变流量、溢流阀调定压力、活塞质量、前腔阀口开口长度和中腔阀口开口长度等参数，仿真分析了各参数对冲击性能的影响规律。结果表明：水压式打桩机冲击器液压系统流量达到额定值后，继续增加流量不能有效提高冲击性能;设置较高的溢流阀调定压力能充分利用输入水压能，显著提高冲击性能;活塞质量增大会降低冲击性能;增大前腔阀口开口长度可以提高冲击性能;增大中腔阀口开口长度反而使冲击性能降低。研究结果为水压式打桩机冲击器结构设计与优化提供了理论依据。

关键词: 水压式打桩机, 水压冲击器, AMESim仿真, 功率键合图