PAFEC-EHL has enhanced facilities for analysing dynamically loaded plain bearing with allowance for distortion of the housing.
High speed engines have light bearing housings which are significantly distorted by the pressures in the oil film. Pressures in the oil film satisfy Reynolds equation in which the thickness, h, of the oil film, and hence the housing distortion, play a very important part. Therefore the structural distortion and the pressure distribution are very strongly coupled and a combined solution is needed.
PAFEC-EHL 2.2 – Functional Overview
- Mass continuity in the fluid film based on Reynolds equation with an implicit time integration scheme giving a formulation in pressure and journal articulation.
- Range of linear and quadratic triangular and quadrilateral fluid element types.
- Arbitrary spatial discretisation of the fluid film and structural housing surface.
- Inclusion of inertia or other (non-fluid) loads in the bearing housing deformation at each time step.
- Arbitrary specification of the initial clearance over the fluid film.
- Time dependent specification of journal translation and tilt or applied forces and moments.
- Rotating pressures simulating journal oil supply.
- Mass conserving and quasi-static cavitation algorithms. Sommerfeld boundary conditions also available.
- Stochastic or general 3D surface roughness.
- Variable fluid viscosity.
- Solution of the coupled Reynolds and journal equilibrium equations using Newton-Raphson techniques which accurately determined Jacobian matrices.
- Equation solution options for the full non-symmetric equations (Gaussian or LU reduction) or sparse frontal solution for rigid housings.
- Flexible control of the incremental/iterative solution including cyclic convergence.
- Full solution restart capabilities.
- Output of pressures, film thicknesses and housing deformations to neutral format nodal result files or IDEAS universal file.
- Summary of key bearing performance indicators for the last converged cycle including friction, side flow, power loss etc.
- Film pressures projected onto the bearing surface for stress analysis of the housing.