The Stress Analysis And Dynamic Strain Measurement Of Piston Rod In Rapping Device Of Gasifer

In the paper, the piston rod that is the role of energy transfer in mechanical rapping-off-ash device is investigated. In the case of work, it is easy to be interrupted for the piston rod. To solve this problem, we use fracture mechanics to study fracture mechanism of the piston rod. Stress Analysis of the piston rod is based on the dynamics of elasticity and impact, This paper describes the theoretical knowledge of impact and elasticity which are involved in depth.The stress on the piston rod is simulated basing on ANSYS/LS-DYNA and the strain on the dangerous parts of piston rod is tested by test.The stress of the piston rod is analyzed baseing on ANSYS/LS-DYNA, in order to simplifying the process of problem analysis, force of the impact on the piston rod is taken as the form of triangular pulse load, whose time is lasting 0.05s, and it can get the maximum load in 0.025s. From the perspective of the stress, simulating the stress distribution under the various fillet radius and the different thickness of the the piston rod step.By calculating,it is good enough for requirements when the fillet radius is 5mm and the thickness of step is 3mm. Because of cross-section changes,tensile stress will be produce in the transmission process of stress wave,tensile stress makes the piston rod of the fracture occur at the top of the steps. In addition, the location of stress concentration is broken easily, the analysis reaches that chamfering position and the the bottom of the piston rod are dangerous section through Z-direction stress cloud and the Von mises stress cloud .In addition, though searching related information, selecting the piston rod materials that should be absorb impact is also a slight introduction.We did some experiments on the piston rod with modern test technique.Combining with the basic knowledge of impact dynamics and the requirements of system, a detailed designing scheme of testing bed was presented and finally brought the test bed a forming assembly. The virtual instrumental technique has been adop ted, the testing system of impact signal constituted by hardwares of sensor, data collection card and computer was constructed, thus realized an optimized combination of functional requirements and economic cost. The programs of data processing and analysis system were designed at the LabVIEW platform and realized the transformation from indirect data into the direct data. Finally a comparison on the test result of this system with the computer simulation was given out. The identical between the finite element analysis results and the experiment results indicates that the finite element analysis is right.