In MESYS shaft calculation or the shaft system calculation FEA based 3D-elastic parts can be considered for more accurate stiffness of the system. Shafts, housings, planet carriers or gear bodies can be considered as 3D-elastic parts. Elastic deformations of shafts and housings can be considered as elastic deformations of bearing rings. The 3D-elastic parts are once reduced statically and optionally modally and afterwards the calculation time per load case is still small. The following possibilities are available:

  • Import of shafts, housings or planet carriers as STEP or Nastran-mesh
  • Parametric definition of shafts and planet carriers
  • Meshing within the software as hexahadral dominant or thetrahedral, either with linear or quadratic shape functions
  • One temparture per part can be defined. Thermal deformation will be considered.
  • Centrifugal expansion for rotating shafts and planet carriers can be considered optionally.
  • Consideration of weight
  • Static reduction and optional model reduction
  • Elastic deformation of bearing rings optionally with contact
  • Elastic deformation of gear bodies
  • Definition of boundary conditions on 3D-elastic parts
  • Definition of forces on the 3D-elastic part
  • Output of displacements for reduction points
  • Optional calculation of stiffness for reduction points
  • Display of deformed shape
  • 3D-animation of natural frequencies or harmonic response for model reduction and calculation of natural frequencies

Elastic planet carriers

The elastic deformations of the planet carries have an influence on the load distribution of the gears and therefore should be considered at design of tooth trace corrections. The tilting of the planets will also have an influence on the bearing loads and the global torsional stiffness. The deformations can be determined more accurately with the correct geometry than using simplified hollow shaft

Planet stage with elastic planet carrier

Planet carrier with deformations

Planet carriers can be imported as CAD-model or be defined parametrically. Four basic variants are available for the parametric planet carriers.

Basic types of parametric planet carriers

Elastic housings

Using elastic housings the stiffness of supports can be taken into account more accurately in the static calculation and also for natural frequencies. The influence on natural frequencies is much larger compared to the influence on static deformations.

Imported housing from STEP file (Courtesy RPT Tech GmbH)

Spindle test stand with elastic housing (Video)

Elastic bearing rings

Elastic bearing rings can be considered for large bearing like in wind turbines as example:

Elastic parts with elastic bearing rings

Further examples are a wheel bearing with interference between outer ring and housing without additional loads and a piston-rod:

Load distribution for a wheel bearing with interference between outer ring and housing

Piston-rod with elastic bearing rings under pressure and tension

Elastic gear bodies

Elastic deformations of gear bodies have an influence on the load distribution in the gear contact and on global stiffness. A webbed helical gear can deform in axial direction for example:

Elastic gear body with helical gear

For planetary gear stages also the combination of elastic gear bodies and elastic bearing rings is possible:

Planetary stage with 3D-elastic planet, ring and carrier