Chapter 27
Rough Estimation of Bolted Joints According to VDI 2230 Sheet 1 (2003-02)

    27.1   Axial Load
    27.2   Transverse Load
    27.3   Strength Grade
    27.4   Load Introduction
    27.5   Tightening Technique
    27.6   Preload
    27.7   Further Possibilities

A bolted joint is a typical connection of two or more parts that are held together by a bolts. The main function of the bolts is to transmit the forces and moments between the connected parts. The minimum bolt diameter can be roughly determined according to the VDI 2230 guideline. The guideline VDI 2230 is one of the common methods of design used for bolted joints. VDI 2230 applies to steel bolts in high-duty and high-strength bolted joints (for strength grades 8.8 to 12.9) and a frictional transmission of the working load. The working load consists of a static or dynamic axial load. In addition, bending moments and transverse loads may occur.

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Figure 27.1: Estimation of bolted joints

With entering the maximum axial load and/or transverse load, the mimimum and maximum preload as well as minimum bolt diameter can be estimated. For the estimation of the transverse load, the friction value is taken into consideration at the interface.

27.1 Axial Load

Axial force \(F_{A}\) is an operating force directed in bolt axis and acting proportionally on a bolt.

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Figure 27.2: Axial load

27.2 Transverse Load

The transverse load \(F_{Q}\) is a load applied perpendicularly to the bolt axis.

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Figure 27.3: Transverse load

Bolted joints are designed that the transverse loads are transmitted to the interface of a preload joint by static friction. It is also possible that the connecting elements (fit bolts, pins, sleeves) transmit transverse loads in a positive manner. Please click the ‘Question mark’ button next to the friction coefficient in order to open the following table. This table shows approximate values for the static friction coefficients at the interface:

Approximate Values for Static Friction Coefficients at the Interface According to VDI 22301
Material Combination
Static Friction Coefficient in the State


Dry Lubricated
Steel - Steel/Cast Steel 0.1 to 0.23 0.07 to 0.12
Steel - Gray Cast Iron 0.12 to 0.24 0.06 to 0.1
Gray Cast Iron - Gray Cast Iron 0.15 to 0.3 0.2
Bronze - Steel 0.12 to 0.28 0.18
Gray Cast Iron - Bronze 0.28 0.15 to 0.2
Steel - Copper Alloy 0.07 -
Steel - Aluminum Alloy 0.1 to 0.28 0.05 to 0.18
Aluminum - Aluminum 0.21 -
1 Table from: VDI 2230, Part 1, February 2003: Systematic Calculation of High Duty Bolted Joints, Joints with One Cylindrical Bolt, Table A6, Approximate Values for Static Friction Coefficients, p. 114

27.3 Strength Grade

The calculation module takes three strength grades into consideration: 8.8, 10.9 and 12.9. The strength grades describe the properties of a bolt (e.g., hardness, tensile strength \(R_{m}\) and yield point \(R_{e}\)). The most common grade for bolted joints is grade 8.8. The strength grades 10.9 and 12.9 are used in particular for preloaded bolted joints.

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Figure 27.4: Strength grade

27.4 Load Introduction

The following options for the selection of the load introduction are available:

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Figure 27.5: Load introduction

Clicking the ‘Question mark’ button next to the listbox opens a new window showing an illustration of the load introduction.

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Figure 27.6: ‘Question mark’ button

Static or Dynamic Transverse Load

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Figure 27.7: Static or dynamic transverse load
Static and Concentric Axial Load

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Figure 27.8: Static and concentric axial force
Dynamic and Concentric Axial Load

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Figure 27.9: Dynamic and concentric axial load
Static and Eccentric Axial Load

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Figure 27.10: Static and eccentric axial load

Dynamic and Eccentric Axial Load

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Figure 27.11: Dynamic and eccentric axial load

27.5 Tightening Technique

The tightening technique may influence the required dimensions of the bolt and must be carefully considered. Select the following tightening techniques from the listbox:

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Figure 27.12: Tightening technique

27.6 Preload

During the assembly of the joint, a preload \(F_{M}\) is produced and this produces a clamp load \(F_{K}\). \(F_{Mmin}\) is the required minimum assembly preload which can occur at \(F_{Mmax}\) resulting from inaccuracies in the tightening technique and maximum friction. \(F_{Mmax}\) is the maximum preload for which a bolt must be designed so that, in spite of inaccuracies in the tightening technique, the required clamp load in the joint is produced and maintained.

27.7 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 27.13: 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 management helps you to start the calculation modules. The list on the left side shows all calculation modules including the free modules. If you use these modules, then no time will be deducted from your account.

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