PDF《Combining KISSsoft&KISSsys with》

Customer Supplier Project Document KISSsoft AG Uetzikon

4 8634 Hombrechtikon Switzerland www.

KISSsoft.ch Title: No.: Date: Manager: @: Version:

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8 G:\KISSSYS\Application-Reports\app-014-combining-KISSsys-FEM.doc Combining KISSsoft&KISSsys with FEM analysis In most cases, a combination of FEM calculation and standardised calculations leads to the most accurate results in the design process. Both methods have their unique strength and disadvantages;

combining the two in a clever way is the most effective approach. While KISSsys and KISSsoft may be used to quickly and reliably generate load data to be exported to the FEM calculation, the resulting deformations as calculated may be used as an input into e.g. the bearing, shaft and load sharing calculation in KISSsoft. Furthermore, stress levels calculated in an FEM analysis may be transformed into a corresponding lifetime or safety factor using KISSsoft rating software. Using the transmission error calculation in KISSsoft to find the variation of the bearing forces, the FEM analysis may be used to find the frequency response and sound pressure levels generated. Natural frequencies of a housing calculated using FEM may be compared with e.g. meshing frequencies of the whole gearbox as calculated in KISSsys. In the same way, bearing fault frequencies may be compared with the natural frequencies found from the FEM analysis. The below report is based on a joint project with VonRoll Casting for the development of a gearbox and its housing. We thank VonRoll Casting for allowing us to publish some results of our joint project. Visit www.vonroll-casting.ch to learn more about VonRoll Casting. Combining KISSsoft & KISSsys with FEM analysis G:\KISSSYS\Application-Reports\app-014-combining-KISSsys-FEM.doc

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8 1.Document information 1.1. Table of content Combining KISSsoft&KISSsys with FEM analysis.1 1. Document information

2 1.1. Table of content.2 1.2. Document change record.2 2. Procedure.2 3. Housing forces.3 4. Bearing support stiffness.4 5. Natural frequency analysis.5 6. Stress level assessment.6 1.2. Document change record Document version Dated Who Comments

0 28.1.2008 HD Original document 2. Procedure It is noteworthy that FEM analysis and the calculations in KISSsoft/KISSsys can interact at different levels of the analysis. Standardised calculations as implemented in KISSsoft are very fast to use and generate input in the form of housing forces for the FEM analysis at no additional modelling effort (see section 3). The housing deformation in return does influence the boundary condition formulation in the KISSsoft shaft analysis, influencing e.g. the gear corrections proposed there (see section 4). Furthermore, parameterised KISSsys models allow for the immediate calculation of exciting frequencies, which may be compared to the natural frequencies obtained from the FEM model (see section 5). Finally, for a given stress distribution calculated in the FEM analysis, KISSsoft can be used to convert stress levels in to a part lifetime or strength (see section 6). The methodology described below is independent of the FEM software used. G:\KISSSYS\Application-Reports\app-014-combining-KISSsys-FEM.doc

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8 3. Housing forces Using an in-built function in KISSsys, all housing forces may be exported for a given load case into a text document or Excel file (see Figure 3-2). The housing forces may also be calculated for a single shaft or a system of concentric shafts using KISSsoft shaft calculation. The housing forces thus documented may then be added in the FEM calculation as shown below (see Figure 3-3). Housing forces are calculated based on meshing forces and element masses. Bearing stiffness (non-linear, including clearance) are considered for statically over-determined systems, bearing pre-tension is considered too. Both the absolute values as well as the direction of the force acting are given as output in tabular form. Figure 3-1 KISSsys model of transmission including housing data, display of housing forces G:\KISSSYS\Application-Reports\app-014-combining-KISSsys-FEM.doc