Version 08-2016 of MESYS shaft and rolling bearing analysis software is available

A new version of the MESYS shaft and rolling bearing analysis software including new functionality is available. The bearing analysis software allows the calculation of the load distribution within the bearing and bearing life according ISO/TS 16281 and it is integrated in a shaft system calculation with additional possibilities like modal analysis, strength calculation for shafts and interfaces to gear calculation programs.

General changes in program usage

Some general improvements are:

• Better support for HighDPI displays. Also multiple monitors with different DPI ratio can be used
• Support for 3D mouse in all 3D graphics
• Opening files by drag&drop

New features in the bearing calculation

The main new features in the bearing calculation are:

• Consideration of elastic expansion/compression for rings with clearance fit
• Angular cylindrical roller bearings as additional bearing type
• Track roller calculation with elastic outer ring now also supported for double row tapered roller bearings
• Load spectra for track rollers can consider loading on multiple points
• New 2D view for the load distribution showing the pressure distribution on the raceway
• Custom setting for rolling element temperature
• Import of additional encrypted bearing databases

Elastic ring expansion

If a bearing ring of an angular contact ball bearing is mounted with clearance and pretension is applied the ring can expand until it makes contact with the housing. This affects the stiffness of the bearing. This effect is now considered by a simplified approach on the basis of thick ring theory. The elastic expansion of a ring under pressure is considered on bearing clearance. The calculation currently uses Dpw+Dw as inner diameter for the outer ring without consideration of the shoulders and allows an additional stiffness factor as input. So without the stiffness factor the ring will be too soft in the calculation and the expansion will be a little too large.

Following image shows a comparison for one example. The bearing calculation uses an expansion of 3.86 μm while an axisymmetric FEA would lead to a maximum value of 3.68 μm. So the stiffness factor could be chosen to 1.049 to correct this error. Taking into account that all parameters have tolerances an error below 1μm could be ignored in most cases.

New features in the shaft calculation

The main new features in the shaft calculation are:

• New graphic windows for bearing overviews show the same graphic for all bearings in a system
• CAD Import of shaft geometry as 2D DXF or 3D Step
• CAD export of geometry as 3D Step
• Import of 3D Housing as Step file which can be connected to the supports in the system
• New calculation method for harmonic response
• Global setting for Raleigh damping
• Shaft geometry shown as background image in diagrams
• Optional measurement lines for forces and supports in 2D view of shaft geometry

Overview graphics for bearings

Images are often helpful to understand the behavior of a shaft system. Instead of graphics for each bearing only, the shaft calculation now also offers overview graphics with information for all bearings in one view. See following image for an example for a shaft with one ball and one roller bearing.

Dimensions for shaft supports and forces

Following image shows an example for dimensions in the 2D graphics.

CAD-Import of shaft geometry

Usually the input of shaft geometry as cylinder and cone elements is quickly done, but there had been requests for import of shaft geometry from CAD files. An import from 2D DXF or 3D Step files was added for version 08-2016.

Importing geometry from CAD format can lead to many small elements if, for example, many relief grooves are considered. Therefore, it might be helpful to disable some features in the CAD system before export. The shaft calculation considers only axial symmetric geometry, so only the geometry in the x/y-plane is imported from a 3D step file.

Import of a housing as STEP file

A housing can be imported as step file and considered as stiffness in the calculation of the shaft system. The CAD model will be meshed and reduced to a stiffness matrix automatically.

3D elastic parts as axisymmetric shafts

An axisymmetric part can be defined using a polygon. It will be meshed and the stiffness can be considered with the shaft model. Selected faces or edges of the 3D part can be connected to a shaft support.

These models can be used in special cases where a beam could be too stiff.