The Finite Element Analysis Of The Combined Piston

As one of the key parts of the engine, piston working in the extremely harsh conditions may stand high thermal and mechanic loads. Thermal load and mechanic load coupling make piston to produce crackle, scuffing of cylinder, sticking of cylinder and piston-ring gumming and so on. These failures greatly limit the engines'durability and reliability. So calculating and analyzing the piston temperature field, force field and coupling load that thermal and mechanic load act on together in conformity with the force field, finding out the thermal load and the stress distribution situation, so to improve the piston working dependability is significant.Firstly, based on a widely reading relevant articles, the thermal and mechanic boundary conditions of a certain diesel piston are discussed and the temperature, thermal stress, mechanic stress, coupling stress that thermal and mechanic load act together are calculated by Finite Element method. The result reveals that the piston head is main influenced by thermal stress, and the piston skirt is main influenced by mechanic stress.Secondly, the temperature field and the coupling stress of the piston under different working conditions were calculated and analysised. The results show that the load increase, the temperature and the coupling stress corresponding increase.Thirdly, this paper calculates the temperature and the coupling stress of the piston without cooling. And on the basis, the strength of the connecting bolt is checked. The results reveals that piston without cooling with higher thermal load than thepiston with cooling. The high thermal load causes the piston head creating a great deformation.