Research On Modeling Method Of The Helicopter Main Drive System’s Typical Gear Fault Based On Multi-body Dynamics

Helicopter plays an important role in military and civilian traffic. Its main drive system is the key of the helicopter core parts. Carrying out fault diagnosis research of the helicopter main drive system has the important Significance to ensure the safe and reliable operation of the helic opter. It is d ifficult to obtain f ault data by us ing the method of building experimental platform for complicate structure of helicopter main drive system, which restricted fa ult diagnosis technology research of the helicopter main drive system. Aiming at this proble m, this thes is builds m ulti-body dynamics model of the helicopter main drive system containing gear fault by the method of fault modeling, and researchs gear fault evolution law of main drive system by the signal of simulation. Research results can provide a certain basis and guidance for he licopter transmission system fault diagnosis, and also provide a new way for large mechanical system fault diagnosis.Main research content of paper is as follows:(1) Modeling m ethod research of the gear system can reflect vibration transmission characteristics. The gearbox fault si mulation test bench of Am erica Spectra Quest company as the backing, and carrying out modeling method research of the gear system can reflect v ibration transmission characteristics. Three-dimensional entity model of gear system was established in CATIA, and im ported to ADAMS by using a p rofessional interface software Sim Designer of CATI A and ADAMS. The drive shaft and gears are flexible processing, define motion pair, add the contact force and load, si mulate support of box structure and experim ent platform by spring-damper gear, so that ensure the body can reflect the vibration, calculate the time-varying gear contact st iffness coefficient, many times simulation to de termine the torsional spring stiffness and contact dam ping force. So gear syste m dynamics model is es tablished successfully considering time-varying contact stiffnes s, gear wheel body torsion deform ation, tooth bendi ng deformation and the shaft torsional deformation and reaction of th e vibration transfer charac teristics, and carrying out simulation analysis, the simulation results obtained verification of the theoretical and experimental, proving the validity of the modeling method.(2) Implanted method research of typical gear fault model. Studied the gear fault into model m ethods based on this the right model: using characteristics command in CATIA to set up gear failure of the three-dim ensional entity m odel, through Sim Designer im port to ADAMS, a nd ADAMS is used to derive the three-dimensional entity model whose file type is parasolid(xmt_txt format), and then through Location coordinates and Orientat ion position Marker point corresponding the normal gear of the f ault gear to loc ate the coordinates that is m atching of the normal gear position. Also analyzed two kinds of failures about local broken teeth and tooth broke in the in fluence of time-varying meshing contact stiffness coefficient of gear, to calculate gear mesh stiffness coefficient of contact has changed, and on this basis to add fault gear corresponding constraints and contact force, getting multi-body dynamics model of gear system contains gear fault, It is verified for experim ent, proving implanted method of the gear fault model.(3) Gear fault m odeling and fault evolution law research of the helicop ter main transmission system. Based on the above research and obtained gear system modeling method can reflect the vibration transfer ch aracteristics and typi cal fault gear into method, carrying out study on gear fault modeling method of helicopter m ain transmission system, respectively established the main drive system of planetary gear train trouble-free and local broken teeth, tooth broke two kinds of the m ulti-body dynamics model of gear fault vibration simulation, and obtained simulation signals, it is analyzed to obtain the typical fault evolution law of the helicopter main drive gear planetary gear train wheel. The sim ulation signal also can be a pplied to helicopter main drive system of fault diagnosis as the source signal.