Section 1 Definition of Stress Concentration Factors in crankshaft fillets
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 1 Guidance for Calculation of Stress Concentration Factors in the Web Fillet Radii of Crankshafts Through the Utilisation of the Finite Element Method - Section 1 Definition of Stress Concentration Factors in crankshaft fillets

Section 1 Definition of Stress Concentration Factors in crankshaft fillets

Parent topic: Chapter 1 Guidance for Calculation of Stress Concentration Factors in the Web Fillet Radii of Crankshafts Through the Utilisation of the Finite Element Method

1.1 General

1.1.1 The objective of the analysis is to develop Finite Element Method (FEM) calculated figures as an alternative to the analytically calculated Stress Concentration Factors (SCF) for the crankshaft fillets. The analytical method is based on empirical formulae developed from strain gauge measurements of various crank geometries, and therefore the application of these formulae is limited to those geometries.

1.1.2 The SCFs calculated according to the rules of this document are defined as the ratio of stresses calculated by FEM to nominal stresses in both journal and pin fillets. When used in connection with the present method in the applicable Rules or the alternative methods, von Mises stresses shall be calculated for bending, and principal stresses for torsion. Care should be taken to avoid mixing equivalent (von Mises) stresses and principal stresses.

1.1.3 This guidance, as well as that contained in Ch 2 Guidance for Evaluation of Fatigue Tests, is valid for both solid cranks and semi-built cranks, except journal fillets.

1.1.4 The analysis is to be conducted as linear elastic FE analysis, and unit loads of appropriate magnitude are to be applied for all load cases.

1.1.5 The calculation of SCF at the oil bores is not covered by this chapter.

1.1.6 It is advised that the element accuracy of the FE solver in use is checked, e.g. by modelling a simple geometry and comparing the stresses obtained by FEM with the analytical solution for pure bending and torsion.

1.1.7 Boundary Element Method (BEM) may be used instead of FEM.

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