Improper sealing mechanisms of oil tanks in automobiles or storage may lead to contamination of the oil or oil leaks. Since oil is a highly combustible substance, leakages can be highly dangerous and even fatal. To prevent this from happening, oil seals are used. A large number of oil seals are made from Polytetrafluoroethylene or PTFE due to their low friction and minimum power consumption advantages. These seals may be used either with lubrication or in dry environments where there is insufficient lubrication.
Oil seals undergo a large amount of mechanical and thermal stress depending upon the application they are used for. To ensure that they don’t deform or undergo fracture under these conditions, engineers need to make a robust design with the right choice of material. Finite Element Analysis (FEA) enables us to simulate how the oil seal would react under stress and gives us data to ponder upon what could be done to prevent this.
In this project, a stress analysis (FEA) of a PTFE oil seal is performed both with friction and without friction.
Due to symmetry, only a portion of the seal with a steel shaft is considered. The geometry is then uploaded onto the SimScale platform and is shown below.
A fully automatic tet-dominant mesh is mapped onto the entire geometry. The mesh is of the first order and uses 2 computational cores.
A **nonlinear, static, structural analysis is performed, both for frictionless and frictional cases. An augmented Lagrange contact is used for the frictionless case and a penalty contact for the case involving friction. Two values of the frictional coefficient are considered- 0.7 and 0.9. The shaft is assigned to be steel and the seal is taken to be hyperelastic PTFE material. The shaft is inserted in the seal by displacing it in the positive z-direction.
Results and Conclusions
The results below show the von Mises stress formed in the seal without friction and with friction (coefficient= 0.9). It is worth noting that there are more stresses acting on the seal in case of friction.
The graph below shows the von Mises stress on the seal with and without friction.
Finally, the figure below shows an animation of the final result.