Design Of High-temperature Rotary Flexure Fatigue Testing Machine For Aircraft Tube Fittings

In the development of many tube-line systems for aerospace vehicles,its performance will directly determine the safety of aircraft performance.The use of new materials for catheters and their components and the research of new joining processes are still the hotspots of scholars today.Aviation duct materials are mainly aluminum alloy,stainless steel and titanium alloy,the detachable catheter assembly is mainly available in the form of flares,unflared,and joints such as memory alloys.The bending fatigue test of the duct assembly is one of the important methods to evaluate the reliability and durability of various types of tube joints,and the rotary flexure fatigue testing machine is a necessary test equipment.In order to accurately detect the rotary flexure fatigue life of the catheter assembly under various specifications and different environmental conditions,guided by the relevant standard theory such as navigation mark and national military standard,based on the research of room temperature rotary duct bending fatigue testing machine,this paper develops the design and research work of the high temperature rotary bending fatigue testing machine for aviation ducts.The modular analysis method divides the whole machine into eight subsystems.After careful analysis and demonstration,it is determined that the electromagnetic induction heating method is suitable for the test machine,and the perfect cooperation between the high-temperature heating device and the testing machine is realized in a small space with a width of 200 mm and a height of 150 mm in a single position of the testing machine.The 1Cr18Ni9 Ti stainless steel tube assembly,which has an outer diameter of 12 mm,an inner diameter of 10.2 mm,a wall thickness of 0.9 mm,and a length of 266 mm,is a research object,and a circular cross-section induction coil are used to establish a finite element model.The finite element simulation results show that the highest temperature in the assessment area is 651°C,the lowest temperature is 648.3°C,and the error is 1.7°C,within the industrial requirements error range,it can be applied to the actual high-temperature rotary flexure fatigue test.