Stress Intensity Factors and Possible Crack Propagation Mechanisms for a Crack Surface in a Polyethylene Tibia Component Subject to Rolling and Sliding Contact

2003 ◽  
Vol 27 (12) ◽  
pp. 2019-2027
2020 ◽  
Author(s):  
Ondrej Slávik ◽  
Pavel Hutař ◽  
Michael Berer ◽  
Anja Gosch ◽  
Tomáš Vojtek ◽  
...  

1989 ◽  
Vol 111 (2) ◽  
pp. 172-176 ◽  
Author(s):  
Y. M. Tsai

The dynamic response of a central crack in an orthotropic material is investigated. The crack is situated along one of the principal axes of the material. The load is harmonic in time and normally applied to the crack surface. The Fourier transform is used to solve the dynamic fracture problem, and the results are simplified through a complete contour integration. The dynamic stress intensity factor is obtained in an exact expression in terms of the frequency factor and the material constants. The frequency factor is defined as the product of the wave frequency and the half-crack length, divided by the shear wave speed. Glass/epoxy and graphite/epoxy composite materials are used as example materials in calculating the numerical values of the stress intensity factors. The maximum values of the stress intensity factors are shown to be dependent on the value of the nondimensional frequency factor and the material anisotropy. The motion of the crack surface is also investigated. The crack surface distortion from the associated static crack shape also depends on the wave frequency and the orthotropic material constants.


1988 ◽  
Vol 110 (3) ◽  
pp. 408-413 ◽  
Author(s):  
L. J. Ghosn

Crack propagation in a rotating inner raceway of a high-speed roller bearing is analyzed using the boundary integral method. The model consists of an edge plate under plane strain condition upon which varying Hertzian stress fields are superimposed. A multidomain boundary integral equation using quadratic elements was written to determine the stress intensity factors KI and KII at the crack tip for various roller positions. The multidomain formulation allows the two faces of the crack to be modeled in two different subregions making it possible to analyze crack closure when the roller is positioned on or close to the crack line. KI and KII stress intensity factors along any direction were computed. These calculations permit determination of crack growth direction along which the average KI times the alternating KI is maximum.


1982 ◽  
Vol 104 (4) ◽  
pp. 299-307 ◽  
Author(s):  
T. Nishioka ◽  
S. N. Atluri

An alternating method, in conjunction with the finite element method and a newly developed analytical solution for an elliptical crack in an infinite solid, is used to determine stress intensity factors for semi-elliptical surface flaws in cylindrical pressure vessels. The present finite element alternating method leads to a very inexpensive procedure for routine evaluation of accurate stress intensity factors for flawed pressure vessels. The problems considered in the present paper are: (i) an outer semi-elliptical surface crack in a thick cylinder, and (ii) inner semi-elliptical surface cracks in a thin cylinder which were recommended for analysis by the ASME Boiler and Pressure Vessel Code (Section III, App. G, 1977). For each crack geometry of an inner surface crack, seven independent loadings, such as internal pressure loading on the cylinder surface and polynomial pressure loadings from constant to fifth order on the crack surface, are considered. From the analyses of these loadings, the magnification factors for the internal pressure loading and the polynomial influence functions for the polynomial crack surface loadings are determined. By the method of superposition, the magnification factors for internally pressurized cylinders are rederived by using the polynomial influence functions to check the internal consistency of the present analysis. These values agree excellently with the magnification factors obtained directly. The present results are also compared with the results available in literature.


1992 ◽  
Vol 114 (4) ◽  
pp. 690-697 ◽  
Author(s):  
H. Salehizadeh ◽  
N. Saka

The stress intensity factors for short straight and branched subsurface cracks subjected to a Hertzian loading are calculated by the finite element method. The effect of crack face friction on stress intensity factors is considered for both straight and branched cracks. The calculations show that the straight crack is subjected to pure mode II loading, whereas the branched crack is subjected to both mode I and mode II, with ΔKI/ΔKII < 0.25. Although KI is small, it strongly influences KII by keeping the branched crack faces apart. Based on the ΔKII values and Paris’s crack growth model, the number of stress reversals required to grow a crack in a rolling component from an initial threshold length to the final spalling length was estimated. It was found that the crack propagation period is small compared with the expected bearing fatigue life. Therefore, crack propagation is not the rate controlling factor in the fatigue failure of bearings operating under normal loading levels.


2011 ◽  
Vol 250-253 ◽  
pp. 1856-1861
Author(s):  
Li Jun Lu ◽  
Jian Ping Liu ◽  
Zhong Mei Li

This paper focusing on the crack at hole of guyed-mast’s ear-plate connecting cables and shaft of guyed-mast, adopting two degree of freedom crack propagation model, track the crack propagation according to the increment of the deepest point and the surface point on the crack front of crack at hole of guyed-mast’s ear-plate. The stress intensity factors of I,II and III type crack with given shape and size have been calculated via finite element method, and a numerical method of calculating stress intensity factors with any shape and size crack has been proposed; furthermore according to modified I, II and III type compound crack propagation velocity formula on the basis of Paris crack propagation velocity formula, we analyzed the changing of crack shape parameter a/c with crack size parameter a/T of crack at hole of ear-plate connecting cable and shaft of guyed-mast by numerical integration method and obtained the propagation characteristic.


2007 ◽  
Vol 348-349 ◽  
pp. 585-588
Author(s):  
Henning Schütte ◽  
Kianoush Molla-Abbasi

The aim of the presentation is to highlight the influence of the kink, developing at the beginning of mixed-mode crack growth, on the propagation behavior of the crack. Le et al. [1] have shown that the variational principle of a body containing a crack results in the principle of maximum energy release rate incorporating the stress intensity factors of the kinked crack. Here the influence of the kink and the kinking angle, resulting in a singular field around the corner, on the crack growth is analyzed. The generalized stress intensity factors at the kinks corner are computed with the help of a FEM strategy. The influence of these on the T-stresses and the plastic energy dissipated at the kink is determined using a small scale yielding approach. The impact of these results on mixed-mode crack propagation is discussed.


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