Chapter 18
Approximate Shaft Dimensioning According to Niemann 2001, 3rd Edition, Page 742

    18.1   Material Selection
    18.2   Material Number
    18.3   Load Types
    18.4   Further Possibilities

The required dimensions for the design of shafts and axes with full circular cross-section will be estimated with an approximate calculation. It is assumed that the main load is well-known.

‘The permissible nominal torsional stress is set so low that the neglected bending stress will be considered as well as increasing stresses due to impact forces (external forces), notches, cross-sections, etc. The basis for the design of axes under bending stress is the nominal stress’ (from Niemann 2001, 3. edition p. 741).

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Figure 18.1: Shaft dimensioning

The material can be selected for the calculation from the database. It is also possible to use individual material by the default of the maximum permissible torsion and bending tension.

18.1 Material Selection

For the calculation the material can be selected from the following listbox.

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Figure 18.2: Material selection

18.1.1 Define your Own Material

In case you cannot find the material you are looking for in our extensive database, simply define your individual material. You will find the entry ‘User-defined’ in the listbox. If you select this option, the input fields will be enabled, so that you can enter your own input values.

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Figure 18.3: User-defined material

18.2 Material Number

Every material has a material number. With the material selection, the material number is displayed automtically. If you have specified an user-defined material, then ‘0.0000’ appears in the listbox ‘Material number’.

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Figure 18.4: Material number

18.3 Load Types

Four different load types are available for the calculation:

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Figure 18.5: Load types

After the input of the load - bending and torsion load or both - as well as the desired safety factor, the required minimum diameter of the axle or shaft is determined.

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Figure 18.6: Required minimum diameter

18.4 Further Possibilities

Clicking the link ‘More calculation modules’ leads you to our web site. Here you can register for a free test account in order to use all eAssistant calculation modules (e.g., shafts, cylindrical gears, bevel gears, springs). Find more information in section 2 ‘Registration’).

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Figure 18.7: Link to our web site

Please Note: If you registrate for the first time, you will receive a password in order to login. The project manager helps you to start the calculation modules. The list window ‘Calculation type’ shows all calculation modules including the free modules. If you use these modules, then no time will be deducted from your account (see section 3.6 ‘Time account’ for more information).

Our manual is improved continually. Of course we are always interested in your opinion, so we would like to know what you think. We appreciate your feedback and we are looking for ideas, suggestions or criticism. If you have anything to say or if you have any questions, please let us know via telephone +49 (0) 531 129 399-0 or email eAssistant@gwj.de.