Investigation on the design and experimental application of novel fatigue testing device for esophagus stent

摘要

One kind of esophagus stent fatigue testing device was developed based on the mathematical analysis of fatigue mechanism of esophagus stent and esophageal motility, in which the esophagus stent was assumed to be under simulated in vivo pre compression load, in vivo creep load and other internal environment. In this device, Cam mechanism was creatively used to simulate the esophageal peristaltic wave. which was simple and compact in the fast response speed. From the point of view of ensuring the processing precision, the eccentric wheel with lower surface roughness was better than the other structure, which can be easily manufactured on a lathe. Ni-Ti alloy mesh stents were tested by the testing device. The morphology of fatigue fracture section obtained from SEM showed that the heat treatment had a major influence on the fatigue life of stent and the long-term continuous test of stent samples validated the reliability of the testing device. These results indicated that the designed testing device can be applied to test the fatigue life of other self-expanded stents.