On the Contact Stresses at the Indenting Edge of a Shaft-Hub Interference Fit Subject to Bending and Shear Forces

2017 ◽  
Vol 754 ◽  
pp. 157-160
Author(s):  
Enrico Bertocchi ◽  
S. Mantovani ◽  
Antonio Strozzi
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Contact Stresses ◽  
Local Solution ◽  
Time Varying ◽  
Shear Forces ◽  
Interference Fit ◽  
Sharp Notch ◽  
Generalized Stress Intensity Factor ◽  
Bending Loads

The contact stress field is addressed that is developed at the indenting edge of a keyless shaft-hub interference fit, in the case that both bending and shear forces are applied, and in the absence of friction. The combined effect of a set of elementary load cases is assessed for the sharp notch case in terms of a generalized stress intensity factor, with the aid of Finite Elements and for a class of shaft-hub geometries. In fact, linearity is preserved in the case of a sharp edged bore up to the incipient detachment condition; such event, which may occur as a result of e.g. excessive bending loads, may be forecast based on the proposed framework. Contact stresses in the case of rounded edge may be subsequently predicted by scaling an appropriate local solution; fatigue analysis may then be performed in the case of rotating or fluctuating loads. An exhaustive design table is finally compiled to assist the designer in dimensioning an interference fit in the presence of an arbitrary combination of time varying bending and shear forces.

scholarly journals Critical value of the generalized stress intensity factor for a crack perpendicular to an interface

2015 ◽  
Vol 471 (2183) ◽  
pp. 20150571 ◽  
Author(s):  
George G. Adams
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Crack Tip ◽  
Critical Value ◽  
Zone Model ◽  
Cohesive Stress ◽  
Generalized Stress Intensity Factor

When a crack tip impinges upon a bi-material interface, the order of the stress singularity will be equal to, less than or greater than one-half. The generalized stress intensity factors have already been determined for some such configurations, including when a finite-length crack is perpendicular to the interface. However, for these non-square-root singular stresses, the determination of the conditions for crack growth are not well established. In this investigation, the critical value of the generalized stress intensity factor for tensile loading is related to the work of adhesion by using a cohesive zone model in an asymptotic analysis of the separation near the crack tip. It is found that the critical value of the generalized stress intensity factor depends upon the maximum stress of the cohesive zone model, as well as on the Dundurs parameters ( α and β ). As expected this dependence on the cohesive stress vanishes as the material contrast is reduced, in which case the order of the singularity approaches one-half.

scholarly journals Adhesion and pull-off force of an elastic indenter from an elastic half-space

2014 ◽  
Vol 470 (2169) ◽  
pp. 20140317 ◽  
Author(s):  
George G. Adams
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Half Space ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Elastic Half Space ◽  
Work Of Adhesion ◽  
Zone Model ◽  
Generalized Stress Intensity Factor ◽  
Elastic Punch

The adhesion between an elastic punch and an elastic half-space is investigated for plane and axisymmetric geometries. The pull-off force is determined for a range of material combinations. This configuration is characterized by a generalized stress intensity factor which has an order less than one-half. The critical value of this generalized stress intensity factor is related to the work of adhesion, under tensile loading, by using a cohesive zone model in an asymptotic analysis of the separation near the elastic punch corner. These results are used in conjunction with existing results in the literature for the frictionless contact between an elastic semi-infinite strip and half-space in both plane and axisymmetric configurations. It is found that the value of the pull-off force includes a dependence on the maximum stress of the cohesive zone model. As expected, this dependence vanishes as the punch becomes rigid in that case the order of the singularity approaches one-half. At the other limit, when the half-space becomes rigid, the stresses become bounded and uniform and the pull-off force depends linearly on the cohesive stress and is independent of the work of adhesion. Thus, the transition from fracture-dominated adhesion to strength-dominated adhesion is demonstrated.

Examination on Flaw Interactions in a Plate Subjected to Tensile and Bending Loads

2021 ◽  
Author(s):  
Yeong Cheol Im ◽  
Myung Hyun Kim
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Multiple Cracks ◽  
Element Analysis ◽  
Metallic Structures ◽  
Parametric Studies ◽  
Bending Loads ◽  
Conservative Estimation ◽  
Embedded Crack

Abstract Engineering Critical Assessment (ECA) procedure, which is a method to evaluate the integrity of various structures with embedded crack, surface crack and multiple cracks and so on. In BS7910, the acceptability of flaws in metallic structures is typically dealt with in terms of stress intensity factor solution. For the case with more than two flaws, BS7910 provides various flaw interaction rules. While such flaw interaction rules are developed based on many parametric studies, it is generally known to lead to very conservative results. In this study, the stress intensity factor solutions in a plate with multiple cracks are evaluated. Target structure is a simple plate subjected to tensile and bending loads, and a series of finite element analysis is carried out using ABAQUS. In addition, the results are validated against previous studies available in literatures. Based on the study, the distance criteria for multiple cracks in PD6493 and BS 7910 are found to be overly conservative. Therefore, a parametric investigation regarding the distance between multiple cracks is examined to reduce the overly conservative estimation in existing standards.

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