Effect of crack shape, inclination angle, and friction coefficient in crack surface contact problems

Citation
Na. Noda et al., Effect of crack shape, inclination angle, and friction coefficient in crack surface contact problems, INT J FRACT, 105(4), 2000, pp. 367-389
Citations number
24
Categorie Soggetti
Mechanical Engineering
Journal title
INTERNATIONAL JOURNAL OF FRACTURE
ISSN journal
03769429 → ACNP
Volume
105
Issue
4
Year of publication
2000
Pages
367 - 389
Database
ISI
SICI code
0376-9429(200010)105:4<367:EOCSIA>2.0.ZU;2-6
Abstract
In rolling/sliding contact fatigue, it is known that the crack propagates a t a characteristic angle theta=15-30 deg to the surface. To analyze the mec hanism, however, the body force method has been widely used assuming 3D cra ck models for theta=45-90. In this study, therefore, the unknown body force densities are newly approximated by using fundamental density functions an d polynomials. Then, a semi-elliptical crack model is analyzed for theta=15 -90 under compressive residual stresses and Hertzian contact loads. The str ess intensity factors K-II, K-III are calculated with varying the crack sha pe b/a, inclination crack angle theta, and crack face friction coefficient mu. The calculations show that the present method is useful for the analysi s for theta=15-30 deg with high accuracy. It is seen that the K-II-values w hen b/a --> 0 are larger than the ones when b/a=1 by 0-24% for both under c ompressive residual stress and Hertzian contact load. Regarding the maximum KII values under Hertzian contact load, the results of theta=15 deg are sm aller than the ones of theta=45 deg by 23-34%. Regarding the amplitude of ( K-II max - K-II min), the results of theta=15 deg are smaller than the ones of theta=45 deg by 4-24%. With increasing the value of friction coefficien t mu for crack faces the value of K-II decreases significantly. When the cr ack is short and the inclination angle theta is small, the value of frictio n coefficient f for Hertzian contact load largely affect the K-II value.