Research Of Rotary Bending Fatigue Test For No Flaring Connection Of Aviation Conduit

During the research process of the aircraft, which involves many hydraulic transmission system, the fatigue life-span of the hydraulic conduit system affect the entire safety of the aircraft directly, which is also concerned by many countrys. No flaring aviation hydraulic conduit connection is a new hydraulic conduit connection technology, due to its particularity and novelty, no ready-made fatigue testing data can be used. To ensure its safety ,it is necessary to carry out some relevant tests. There are many factors which can effect the fatigue life of the conduit connection, and the bending fatigue caused by the circulation stress of multiple directions at the end of connection is one of them. In this case, doing rotary bending fatigue test is the most effective way to estimate the fatigue lives of specimen.In order to test the fatigue life of the no flaring aviation conduit connection, basing on the related standards of aviation ministry, referring to other types of rotary bending fatigue testers home and abroad, has designed a set of integrated equipment system,which includes synchronous belt transmission mechanism, spindle mechanism, the deflection adjusting mechanism, fixed mechanism of conduit end and the counting mechanism. The synchronous belt transmission mechanism has been achieved a change of power allocation scheme from one to six successfully, the deflection adjusting mechanism has been achieved the stable effectively regulate of conduit end successfully,and the deflection mechanism has been achieved the purpose of the reliability of installation and guarantee the sealed effect at the same time.This device can do the rotary bending fatigue test for six no belling aviation conduit joints with different deflection value of each one at one time, the tests’efficiency has been greatly increased comparing with the similar ones, it has played a leading role for the design of similar products in domestic. In order to protect intellectual property of the design, it has applied patent for the whole design.A trial tester has been manufactured according to the design successfully. In order to prove the practicability and reliability of the tester, a testing has been done for four groups of conduit connections using the equipment . In the experiments, the tester has completed the intended target and obtained good effect. But some original design problems have been found in the process of experiments also, a careful analysis and summary has been done aiming at the problems and a feasible optimization scheme has been put forward, which can provide some references for the designs of the future.Finite element simulation process also has been done at the same time for the assembly connects method and the reaction in conditions with a certain internal pressure and bending moment in the ends, it has got a series of stress and strain data. The results complies with the reality well comparing with experiment results and has a certain forcast for the experiment results.