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Journal of Failure Analysis and Prevention

, Volume 12, Issue 4, pp 408–418 | Cite as

Characterization of Cut-Edges for Improved Automotive Chassis and Suspension Fatigue CAE Life Predictions

  • Daniel J. Thomas
Technical Article---Peer-Reviewed

Abstract

The durability of safety-critical automotive vehicle steel structures has been observed to be influenced significantly by the condition of the component’s cut-edge properties. The importance of the mechanical cut-edge properties on structural durability has been observed due to surface imperfections generated during the cutting process. These then become the preferred initiation sites for fatigue cracks due to the increased intensity of stress applied to a structure. The current work outlines the development of an improved finite element (FE)-based life prediction method, based on strain-life fatigue data of S355MC steel cut-edges. The resulting best method of predicting fatigue lives of cut-edges using the Coffin–Manson method has been determined as providing the best means for predicting the durability of high strength steel components. This process has been validated using a bespoke laboratory test component representative of those in automotive chassis and suspension assemblies. The outcome of this work is that it allows increased reliance on FE life predictions rather than extensive physical laboratory testing.

Keywords

Coffin–Manson Edge fracture High strength steel fatigue 

Nomenclature

A

Elongation to failure

b

Fatigue strength exponent

c

Fatigue ductility exponent

CAE

Computer aided engineering

\( \varepsilon^{\prime}_{\text{f}} \)

Fatigue ductility coefficient

E-N

Strain-life

FE

Finite element

Hv

Hardness Vickers

HCF

High cycle fatigue

HSS

High strength steel

HSLA

High strength low alloy

K

Cyclic strain hardening coefficient;

Kf

Fatigue reduction factor

LCF

Low cycle fatigue

n

Cyclic strain hardening exponent

\( \sigma^{\prime}_{\text{f}} \)

Fatigue strength coefficient

R

Stress ratio

S-N

Stress-life

SWT

Smith–Watson–Topper

Notes

Acknowledgments

The present research was funded by a grant from the Engineering and Physical Sciences Research Council (EPSRC). The author wishes to thank the support of Swansea University’s Heavy Structures Laboratory during the pursuit of this research.

References

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Copyright information

© ASM International 2012

Authors and Affiliations

  1. 1.College of Engineering, Materials Research CentreSwansea UniversitySwanseaUK

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