scholarly journals CRACK RESISTANCE OF BABBIT B83

2017 ◽  
Vol 2017 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Михаил Зернин ◽  
Mikhail Zernin

Babbit 83 crack resistance test in accordance with SSR 25-506-85 was carried out. By finite element method there were defined values of stress intensity factors in flat samples with a grown crack. The fracture viscosity characteristics of babbit are obtained. On the basis of a macro-fractographic analysis of wear fractures of a babbit sample and a finite element procedure for the definition of values of stress intensity factors the cha-racteristics of cyclic crack resistance are obtained. It is shown that a final fracture is realized at 3 МПа , and a transition from an elastic stage to the stage elastoplastic development of a crack is realized at 2,0…2,8 МПа .

2017 ◽  
Vol 2017 (1) ◽  
pp. 102-111 ◽  
Author(s):  
Михаил Зернин ◽  
Mikhail Zernin

A finite element procedure for calculated inves-tigations of SSS at a crack tip in a babbit layer is created. The procedure is adjusted for bimetal cylin-drical sample loaded according to a circuit of bending with rotation. The dependences for stress intensity factors are obtained and it is shown that accuracy of such modeling is higher than in procedure options used ear-lier. A set of computations for samples with some cracks in a layer is carried out. The criteria of crack separation into independent and interacted are revealed. The results of the work will be used for the further adjusted analysis of experiments and for the formation of dependences in a cyclic crack resistance of babbit layers. The procedure shown and results can be useful for other objects with layers applied on a more solid basis.


2013 ◽  
Vol 353-356 ◽  
pp. 3369-3377 ◽  
Author(s):  
Ming Guang Shi ◽  
Chong Ming Song ◽  
Hong Zhong ◽  
Yan Jie Xu ◽  
Chu Han Zhang

A coupled method between the Scaled Boundary Finite Element Method (SBFEM) and Finite Element Method (FEM) for evaluating the Stress Intensity Factors (SIFs) is presented and achieved on the platform of the commercial finite element software ABAQUS by using Python as the programming language. Automatic transformation of the finite elements around a singular point to a scaled boundary finite element subdomain is realized. This method combines the high accuracy of the SBFEM in computing the SIFs with the ability to handle material nonlinearity as well as powerful mesh generation and post processing ability of commercial FEM software. The validity and accuracy of the method is verified by analysis of several benchmark problems. The coupled algorithm shows a good converging performance, and with minimum additional treatment can be able to handle more problems that cannot be solved by either SBFEM or FEM itself. For fracture problems, it proposes an efficient way to represent stress singularity for problems with complex geometry, loading condition or certain nonlinearity.


Author(s):  
S. W. Ng ◽  
K. J. Lau

Abstract In this paper a procedure is developed to assess the “local” accuracy of weight functions for finding stress intensity factors of centrally cracked finite plates given by Tsai and Ma (1989). It is found that the weight functions can be used to calculate stress intensity factors for practical cases, with “local” accuracy being within 6 %. In addition, weight functions generated from two finite element analyses are found to be accurate and may be used to assess new algorithms for finding weight functions.


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.


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