Notch stress intensity factors under mixed mode loadings: an overview of recent advanced methods for rapid calculation

Peron, Mirco; Razavi, S.M.J.; Berto, Filippo; Torgersen, Jan

doi:10.3221/igf-esis.42.21

Cited by 10 publications

(8 citation statements)

References 26 publications

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“…Welds represent local regions of higher stresses (i.e., stress concentrators) and fatigue failure is widely known to be sensitive to local peak stresses. Thus, over the years, several methods have been developed to assess the fatigue behavior of welds, and among these the Notch Stress Intensity Factor (NSIF) approach is worth mentioning [6][7][8]. In fact, since experimental observations have revealed that the most used welding procedures, such as arc and laser welding, are characterized by a very small weld toe radius, it is acceptable to model it as a sharp notch and the fatigue behavior can thus be correlated to the NSIFs [9,10].…”

Section: Introductionmentioning

confidence: 99%

Fatigue Strength Assessment of Steel Rollers: On the Reliability of the Strain Energy Density Approach on Real Components

Chebat¹,

Peron

Viespoli

et al. 2018

Applied Sciences

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Welded joints are one of the most widely applied methods to join different steel components. However, they introduce stress concentrators that are commonly known to reduce the fatigue strength of structures. Several methods have been developed to assess the fatigue behavior of welded components, such as the Notch Stress Intensity Factors (NSIFs) approach. However, this approach has been reported to be geometry dependent, and does not allow for a direct comparison of failures occurring at the weld toes with those occurring at the weld roots. This drawback has been overcame by considering the value of the strain energy density (SED) range averaged in a control volume ahead of the notch tip. More than 900 fatigue data of welded joints have been summarized within a single scatter band ∆W-N (strain energy range-umber of cycles to failure) using this approach. The reliability of the just mentioned scatter band in summarizing the fatigue data of real components such as steel welded rollers produced by Rulmeca is herein evaluated. The results prove the reliability of the SED approach to assess the fatigue behavior of welded rollers, paving the way to its diffusion in assessing real components.

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Section: Introductionmentioning

confidence: 99%

Fatigue Strength Assessment of Steel Rollers: On the Reliability of the Strain Energy Density Approach on Real Components

Chebat¹,

Peron

Viespoli

et al. 2018

Applied Sciences

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“…Despite these significant advances in understanding the impact of processing conditions on the mechanical behaviour of parts, the effect of geometric discontinuities such as notches is so far underexplored. Yet, this is highly relevant in the field of complex geometric design as such attempts naturally introduce such discontinuities reported to strongly affect both tensile and fatigue properties of the components [16][17][18][19][20][21][22][23][24][25][26]. In fatigue, the effect of notches is unambiguous, determining a reduction in the fatigue strength for several materials [27][28][29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Fracture behaviour of notched as-built EBM parts: Characterization and interplay between defects and notch strengthening behaviour

Peron

Torgersen

Ferro

et al. 2018

Theoretical and Applied Fracture Mechanics

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Additive manufacturing (AM) offers the potential to economically produce customized components with complex geometries. However, the introduction of complex geometry goes hand in hand with the presence of notches. Thus, the basic understanding of the tensile behaviour of AM fabricated notched components must be substantially improved so that the unique features of this rapidly developing technology can be utilized in critical load bearing applications. This work aims to assess the tensile behaviour of different notched specimens manufactured by means of the Electron Beam Melting (EBM) technology and tested in their as-built conditions in order to reveal the interplay between notch geometry and AM specific processing. Scanning Electron Microscopy (SEM) was used to investigate the fracture surface of the broken samples, revealing the presence of process-induced defects, harmfully affecting tensile strength with a reduction of 10% and elongation to failure with 40% with respect to values reported in literature for heat treated AM parts, respectively. Interestingly, the authors have discovered an increase in the tensile strength with the severity of the stress concentrators, quite contrary to what is commonly observed for wrought Ti-6Al-4V. This notch strengthening behaviour particular to AM specimens is related to the influence of defects on the failure driving force. The authors provide a qualitative explanation for this phenomenon using 3D FE analyses together with a theoretical description via the ellipse criterion.

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“…Crack-tip field in circumferentially-cracked round bar (CCRB) in tension affected by loss of axial symmetry was explored in [25]. In [26] the overview of recent advanced methods for rapid calculation of notch stress intensity factors under mixed mode loadings was presented. The analytical approach for plane elastic and thermoelastic problems for inhomogeneous, orthotropic planes, half-planes and strips was presented in [27].…”

Section: Introductionmentioning

confidence: 99%

Elastic crack-tip stress field in a semi-strip

Reut

Vaysfeld

Zhuravlova

2018

Frattura Ed Integrità Strutturale

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ABSTRACT. In this article the plain elasticity problem for a semi-strip with a transverse crack is investigated in different cases of boundary conditions at the semi-strip's end. Unlike many works dedicated to this subject, the fixed singularities in the singular integral equation's kernel are considered. The integral transformations' method is applied by a generalized scheme to reduce the initial problem to a one-dimensional problem. The one-dimensional problem is formulated as a vector boundary value problem which is solved with the help of matrix differential calculations and Green's matrix apparatus. The problem is reduced to solve the system of three singular integral equations. Depending on the conditions given on the short edge of the semistrip, the obtained singular integral equation can have one or two fixed singularities. A special method is applied to solve this equation in regard to the singularities existence. Hence, the system of the singular integral equations (SSIE) is solved with the help of the generalized method. The stress intensity factors (SIF) are investigated for different lengths of crack. The novelty of this work is the application of a new approach allowing the consideration of fixed singularities in the problem of a transverse crack in the elastic semi-strip. The comparison of the accuracy of numerical results during the use of different approaches to solve the SSIE is calculated.

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Notch stress intensity factors under mixed mode loadings: an overview of recent advanced methods for rapid calculation

Cited by 10 publications

References 26 publications

Fatigue Strength Assessment of Steel Rollers: On the Reliability of the Strain Energy Density Approach on Real Components

Fatigue Strength Assessment of Steel Rollers: On the Reliability of the Strain Energy Density Approach on Real Components

Fracture behaviour of notched as-built EBM parts: Characterization and interplay between defects and notch strengthening behaviour

Elastic crack-tip stress field in a semi-strip

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