Study On The Key Technology Of Load Occur Device In The Falling Weight Deflectometer

The domestic market of the falling weight deflectometer(FWD) is controlled by the foreign technology, and the performance of domestic like products is bad, especially, the load occur device which simulate hammering action that the load of the cars to the road surface should be advanced in some aspects, such as convenience, rapidity, security, the simulation of dynamic load and so on. So the load occur device of the FWD is designed in this paper, the virtual machine is created. Besides, To solve the problems coming into being in debugging the prototype, dynamic model simulation and analysis are carried on. And according to the simulation data and analysis conclusion, the improvement for the prototype design is achieved.After the structure scenario is determined, a 3-dimension virtual machine of the main portion in the load occur device is created and assembled. Referenced to the virtual machine assembly, the in and out ports of the lifting cylinder and the structural design of the counter weighter are improved, which bring much more convenience to the manufacture and assembly of the compactor and also enhance the reliability of the prototype.A falling weight- carrying system-road surface model is set up, and the responding program is composed with software, which run and figures out the dynamic responding values of the FWD load occur device's performing parameters. Through changing the parameters' values, like isolation parameter, it's influences on the shock mitigation system's performance is analyzed, and the rational range of isolation parameter, while the running conditions of the FWD load occur device are satisfied, is concluded too.In the process of debugging the prototype, the reflection of disengaging device is obtuse. A mathematic model for the fluid cylinder of disengaging device is established. And it is concluded that the friction force which come form lock ring and the spring pressure's inconvenience is the cause of the phenomena. On the base of calculation, the proper range for the parameters of fluid cylinder is determined. The conclusion is referenced to improve the prototype design, and finally the problem of the disengaging device's retardation is solved.