Section 3 Load cases and assessment of stress
Clasification Society 2024 - Version 9.40
Clasifications Register Guidance Information - Guidance Notes for the Calculation of Stress Concentration Factors, Fatigue Enhancement Methods and Evaluation of Fatigue Tests for Crankshafts, July 2021 - Chapter 4 Guidance for Calculation of Stress Concentration Factors in the Oil Bore Outlets of crankshafts through utilisation of the Finite Element Method - Section 3 Load cases and assessment of stress

Section 3 Load cases and assessment of stress

Parent topic: Chapter 4 Guidance for Calculation of Stress Concentration Factors in the Oil Bore Outlets of crankshafts through utilisation of the Finite Element Method

3.1 General

3.1.1 For substitution of the analytically determined SCF in the applicable Rules, calculation shall be performed for the following load cases.

3.2 Torsion

3.2.1 The structure is loaded in pure torsion. The surface warp at the end faces of the model is suppressed.

3.2.2 Torque is applied to the central node, on the crankshaft axis. This node acts as the master node with six degrees of freedom, and is connected rigidly to all nodes of the end face.

3.2.3 The boundary and load conditions are valid for both in-line and V- type engines.

Figure 4.3.1 Boundary and load conditions for the torsion load case

3.2.4 For all nodes in an oil bore outlet, the principal stresses are obtained and the maximum value is taken for subsequent calculation of the SCF:
where the nominal torsion stress τN referred to the crankpin is evaluated per the “Calculation of torsional stresses” sub- Section of the applicable Rules with torque T:

3.3 Bending

3.3.1 The structure is loaded in pure bending. The surface warp at the end faces of the model is suppressed.

3.3.2 The bending moment is applied to the central node on the crankshaft axis. This node acts as the master node, with six degrees of freedom, and is connected rigidly to all nodes of the end face.

3.3.3 The boundary and load conditions are valid for both in-line and V- type engines.

Figure 4.3.2 Boundary and load conditions for the pure bending load case

3.3.4 For all nodes in the oil bore outlet, principal stresses are obtained and the maximum value is taken for subsequent calculation of the SCF:
where the nominal bending stress σN referred to the crankpin is calculated per the “Calculation of bending stresses” sub- Section of the applicable Rules with bending moment M:
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