MultiBody System Simulation Software
Journal Bearing is a Force Element used to model radial or axial journal bearings using a nonlinear stiffness and damping law. This Force Element can model any kind of radial or axial bearing where a force law acting on only two Markers would be unsatisfactory. Simpack Journal Bearing acts between several Markers on the shell and one center Marker on the shaft. A 3D effect can be achieved by adding several Force Elements in a row.
This Force Element is used to simulate hydrodynamic bearings by solving the Reynolds equation accurately and efficiently. The element includes rigid body hydrodynamics (HD), one-sided and double-sided elasto-hydrodynamics (EHD and DEHD). It allows the consideration of global temperature effects (TEHD) in the bearing and the surrounding solids. Special design parameters allow for easy and user friendly consideration of oil bores, grooves etc. Any level of detail can be simulated. The element can also be used to simulate piston ring dynamics
Simpack BEARINX Map for Rolling Bearings enables the software BEARINX® from Schaeffler Technologies to be used in Simpack. BEARINX® allows the calculation of accurate bearing forces and torques for a large number of rolling bearings.
Non-linear stiffness as well as coupling effects and bearing clearance are described by a characteristic field in a BEARINX Map (.bxm) file, which must be provided by Schaeffler Technologies.
Engineer’s Obstacles in Rolling Bearing Design and Selection
Bearings are the most frequently used machine element in power transmission. A poorly designed rolling bearing can quickly lead to damages of the bearing itself and/or the drive train. In worst case, a chain reaction induces the total loss of your complete system. Thanks to detailed basic research works (e.g. PALMGREN, LUNDBERG, GAERTNER, see ,  and ), standardized formulas were introduced to enable engineers to properly design and select bearings in terms of carrying capacity by means of the bearings load spectrum. To calculate a reliable lifetime expectancy, the load spectrum has to be as realistic as possible. However, due to unknown operational loads and complex interactions between the bearing and the system, the required representational bearing loads are hard to estimate. Besides this, the demand on decreasing acoustic emission and detailed transfer path analysis is growing, which raises questions regarding the detailed rolling bearing dynamics and its influence on the system dynamics. To cover all these highly involved design topics confronting nowadays engineers, powerful tools for the dynamic roller bearing and system analysis are required.
Simpack Rolling Bearing
To address the mentioned obstacles in Rolling Bearing analysis, Simpack offers the Force Element “Rolling Bearing”. This Force Element efficiently simulates all common types of rolling bearings by resolving the rolling element contacts under consideration of the inner geometry. On one hand, this takes the detailed transmitting behavior of a bearing into account, because the non-linear stiffness characteristics, clearance and cross-coupling are automatically considered. On the other hand, the approach covers the excitations generated by the bearing (e.g. due to rolling elements passing through the loaded zone). The high efficiency of this Force Element and the consideration of the transmitting and excitation effects of a bearing enable the engineer to generate realistic load spectra, which take the interaction of the rolling bearing with the complete system into account. In terms of carrying capacity, lightweight construction, and acoustic emission, this element makes the design and selection of the best bearing solution much easier.
Supported Bearing Types
- Ball Bearings: deep groove, angular, thrust, four point
- Cylinder / Needle: radial, thrust
- Tapered Roller Bearing
- Barrel and Spherical Roller Bearings
- Local contact evaluation considering inner geometry: Non-linear stiffness, cross-coupling, clearance
- Complete customization possible (pitch diameter, number of rolling elements, rolling element diameter, groove radii, roller profile, taper angle, …)
- Modeling per row concept: Design as much bearing rows as you want
- User defined friction: Load dependent and load independent friction portions, speed dependent friction coefficient
- Local contact damping
- Minimize the risk of an overdamped rolling bearing setup
- Flexible bearings, even for multi row bearings
- Real-time capable (Convince yourself: Just test the example models provided within the Simpack documentation)
- Due to high performance, the force element can be used for holistic simulations
Analysis and Outputs
- Fast, robust and accurate simulation of roller bearings as a standalone model or as part of a complete system
- Overall radial, axial and tilting loads
- Radial and axial loads per rolling element
- Deflection of the complete bearing and of single rollers
- Contact pressure
- Load distribution (e.g. to calculate the modified reference rating life according to ISO16281 )
- Power loss and friction torque
- General flexible body outputs provided by Simpack (see Flexible Body Simulation Modules)
Example for a standalone and holistic bearing simulation
Analyze load distribution with variant roller profiles:
 Gaertner: Ueber die Lebensdauer von Kugellagern, Dinglers Polytechnisches Journal, 1918
 Palmgren, A.: Ball and roller bearing engineering. 2nd Edition. S.H. Burband & Co., Inc., Philadelphia, 1945.
 ISO 16281: Rolling bearings — Methods for calculating the modified reference rating life for universally loaded bearings. ISO 16281, Technical Specification. June 2018
 Schlecht, B.: Maschinenelemente 2: Getriebe, Verzahnungen, Lagerungen. München: Pearson Studium, 2010.