PSI - Issue 35

Gaston Haidak et al. / Procedia Structural Integrity 35 (2022) 124–131 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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where b represents the body forces and σ is the infinitesimal stress tensor. The second is that of the behaviour of the fluid. The instantaneous lubricating oil film thickness ( h), which is expressed as a function of three different points h 1 , h 2 , and h 3 on the outer edge of the slipper with the interval of 120° from each other, developed in (Haidak et al., 2018) can be used and transformed into cylindrical coordinate (Eq. 2) to calculate the fluid film thickness between slipper and swashplate; assuming that the slipper and swashplate surfaces are ideally smooth and neglecting the deformation of the slipper and the swashplate(Schenk and Ivantysynova, 2015). ℎ = . 0 . √3 ( ℎ 2 − ℎ 3 ) + . 3 . 0 (2. ℎ 1 − ℎ 2 − ℎ 3 ) + 1 3 ( ℎ 1 + ℎ 2 + ℎ 3 ) (2) where ℎ 1 represents the rigid film thickness, is the rotational angle varying between 0 and 2 , the radius varying between 0 and the outer diameter of slipper and 0 the slipper orifice radius. Therefore, the final fluid film thickness between the slipper and swashplate is the summation of ℎ 1 , the pressure/thermal deformation of the slipper ( ), and for swashplate ( ) as given in Eq. (3). ℎ = ℎ1 + − (3) Three primary loops for the numerical calculation are formed from combining these above equations. In Fig. 2, the first loop (green arrows) is executed at the beginning of every time step; this step is for the pre-processing of simulation, including setting initial conditions. The second loop (red arrows) helps to optimise mesh structure and its convergence; the balance of solid body deformation is checked under the loop (blue arrows). Finally, the pressure of structural body deformation is resolved and updating the temperature and viscosity of the fluid film. The modifications in the solid body deformation are relaxed at the beginning of the iterations of each loop.

Fig. 2. Flowchart of the proposed numerical simulation model