Fatigue Strength Evaluation Methods Using Stress Distributions

Abstract:

The stress and displacement fields near the bonding edge, sharp notch, and contact edge show singularity behaviours, so methods of evaluating the strength of these points using maximum stresses calculated by a numerical stress analysis, such as the finite element method, are generally not valid. We have previously presented a new method of evaluating the strength of these singular points using two stress singularity parameters H and λ. In this paper we have developed a method of formularizing critical stress-singularity parameter Hth for each order of stress singularity λ by utilizing critical distance stress theories (point method and line method), which can be derived from two typical strength parameters, namely, fatigue limit σw0 and threshold stress-intensity factor range ΔKth. These estimated critical Hth (λ) value agreed well with the experimentally measured value. Using these simple critical distance stress approach we estimated the fretting-fatigue-crack initiation criteria for any contact edge angle and optimized the contact-edge geometry. Moreover, we apply this new strength criteria to general stress concentration structures.

• Periodical: Key Engineering Materials (Volumes 417-418)
• Pages: 409-412
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.417-418.409
• Online since: October 2009
• Authors: F. Nakamura, Tomoyasu Abe, Toshio Hattori, Minoru Yamashita
• Keywords: Critical Distance Stress, Fatigue Limit, Stress Concentration, Stress Singularity Field, Threshold Stress Intensity Factor Range

References

[1] Hattori, T., Sakata S. and Murakami G., A Stress Singularity Parameter Approach for Evaluating Adhesive Strength, J. Electronic Packaging, Trans ASME, 1-111, 243-248 (1989).

DOI: 10.1115/1.3226542

[2] Hattori, T., A Stress-Singularity-Parameter Approach for Evaluating the Adhesive Strength of Single-Lap Joints, JSME Int. J., Ser. I, 34- 3, 326-331 (1991).

DOI: 10.1299/jsmea1988.34.3_326

[3] Hattori, T. and Nakamura, M., Fretting Fatigue Evaluation Using Stress Singularity Parameters at Contact Edges, Fretting Fatigue, ESIS Publication 18, 453-460 (1994).

[4] Taylor, D., Geometrical Effects in Fatigue: A Unifying Theoretical Model, Int. J. Fatigue, 21, 413-420 (1999).

DOI: 10.1016/s0142-1123(99)00007-9

[5] Kihara, S. and Yoshii, A., Evaluation of the Effect of a Sharp Notch on the Fatigue and Static Strength by the Application of an Stress-Intensity Factor, J. Japan Soc. Mech. Eng. (A) (in Japanese) , 56-524, 903-910 (1990).

DOI: 10.1299/kikaia.56.903

[6] Dempsay, J. P. and Sinclair, G. B., "On the Singular Behavior at the Vertices of a Bi-Material Wedge, J. Elasticity, 11, 317-323 (1981).

[7] Hattori, T., Nakamura, M. and Watanabe, T., Fretting Fatigue Life Simulation Using Stress Singularity Parameters and Fracture Mechanics, JSMS Materials Science Research International, Special Technical Publication-1(Developments of fracture Mechanics for the New Century), 110-117 (2001).

DOI: 10.1016/s0301-679x(02)00141-x

[8] Hattori, T., Sakata, H. and Watanabe, T., Fretting Fatigue Analysis Using Fracture Mechanics, JSME Int. J., Ser. I, 31- 4, 718-723 (1988).

DOI: 10.1299/jsmea1988.31.1_100

[9] Hattori, T., Nakamura, M. and Watanabe, T., Simulation of Fretting-Fatigue Life by Using Stress-Singularity Parameters and Fracture Mechanics, Tribology International, 36, 87-97 (2003).

DOI: 10.1016/s0301-679x(02)00141-x

[10] Hattori, T., Nakamura, M. and Watanabe, T., "Fretting Fatigue Analysis by Using Fracture Mechanics, ASME Paper No. 84-WA/DE-10, (1984).