Shape memory alloys (SMA’s) are known to have many unique properties such as shape memory effect, superelasticity, etc, thus making the materials attractive for application in the medical, aerospace, and automotive industries. Many researchers and engineers are using shape memory alloys to solve existing problems and/or seek new opportunities. In this paper, SMA’s are used in conjunction with lip seals.  Lip seals are known to have the possibility of leakage due both to wear and to a drop in material stiffness as temperature increases.   Explored in this study is the use of SMA to improve seal effectiveness.

While keeping the same functionality of the original, an experimental version of the device was designed. A test rig was developed such that the device could be dynamically tested in an MTS damper test machine. Custom made supplier seals with and without SMA in terms of oil leak rate were evaluated. At the same time, simulation was also done to compare with the experimental results. The model was developed at Northwestern University which is based on 1D Brinson Model assuming 1D SMA behavior in S11 direction and elastic response in other directions. Transverse-isotropic material properties, constant Poisson’s ratio (almost incompressible) and zero thermal expansion were also assumed. The model is then implemented into a 3D UMAT (user defined material) in ABAQUS which inherits all the nice features of a commercial finite element package including support for most continuum elements, contact analysis and even compatible with ABAQUS CAE. Two way shape memory effect (TWSME) was also simulated by shifting the phase diagram since the SMA material exhibits strong two way effect.

Simulations were done on both supplier and SMA enhanced supplier seals which show that more clamping force can be achieved at higher temperatures using SMA that is in line with experimental results.