X‐ray diffraction studies on fatigue crack plastic zones developed under plane strain state conditions

Dias,; Lebrun,; Bignonnet,

doi:10.1046/j.1460-2695.1999.00142.x

Cited by 17 publications

(14 citation statements)

References 13 publications

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“…It is interesting to compare the data obtained for R = 0.1 and Δ K = 13 MPam 1/2 and R = 0.35 and Δ K = 13 MPam 1/2 : in the second case the larger K max causes an increment of the cyclic plastic radius r pc and a deeper plastic zone. This is different from previous observations 12 where the decreasing‐increasing‐decreasing trend is related only to the value Δ K and not to R .…”

Section: Xrd Analysis Of the Crankshaftcontrasting

confidence: 99%

“…Bignonnet et al ., 10 Lebrun et al ., 11 Dias et al 12 . focussed their attention on the relation between the monotonic and cyclic plastic zones extension, the value of K max and Δ K , the measure of the residual stresses and of the FWHM: original results were found, in particular a model for the estimation of the reverse plastic zone in the case of fatigue softening materials that is based on the diffraction peak broadening (FWHM) in‐depth distribution.…”

Section: Introductionmentioning

confidence: 99%

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X‐ray fractography of a diesel engine crankshaft

Pariente

Guagliano

2008

Fatigue Fract Eng Mat Struct

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A B S T R A C T X-ray (XR) diffraction is a well-known experimental technique used for measuring residual stresses in metallic materials. If we apply the XRD technique to the fracture surface of a broken part, it becomes a fractographical technique, that is to say that it is possible to relate the results of the measurement to the loading condition that lead a component to fail. However, in the past this technique was mainly used to analyse standard specimens and not mechanical components and there are few experimental investigations concerning the possibility of using this technique to investigate the cause of fatigue failures. In this paper, after a brief introduction to the technique, XRD fractography is applied to a diesel engine crankshaft that failed under known fatigue loading. It was possible to determine the load that lead the crankshaft to fail and to evidence some original aspects about the application of this technique to real machine parts. Comparison with finite element results served to confirm that XRD can be used as complementary tool to scanning electron microscope (SEM) observation or as a substitute to SEM observation, in the case of damaged fracture surface. N O M E N C L A T U R Ed = interatomic spacing of a family of crystallographic planes E = elastic modulus FWHM = full width at half maximum of the diffraction peak K max = maximum value of the stress intensity factor R = stress ratio of a fatigue cycle r pc = cyclic plastic zone size r pm = monotonic plastic zone size UTS = ultimate tensile strength α = coefficient of relationship between the plastic zone size and the stress intensity factor K = stress intensity factor range ε = strain ψ = angle between the normal of the sample and the normal of the diffracting plane θ = Braggs' angle of the material σ ys = monotonic yield stress σ ys = cyclic yield stress I N T R O D U C T I O NX-ray (XR) diffraction is an experimental technique used in many scientific and industrial fields to measure different properties of materials. It can be applied to crysCorrespondence: M. Guagliano. talline and poly-crystalline materials and consists of measuring the angle of diffraction of an incident XR beam on a surface. In mechanical engineering, XR diffraction is mostly used to measure residual stresses in materials and machine parts: 1,2 the main advantages of this technique with respect to others is that it is non-destructive if used to obtain residual stresses on the surface and that

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Section: Xrd Analysis Of the Crankshaftcontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

X‐ray fractography of a diesel engine crankshaft

Pariente

Guagliano

2008

Fatigue Fract Eng Mat Struct

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“…Given that a diffraction peak is generally broadened by plastic deformation, the variation in the peak full width at half maximum (FWHM) across the fracture surfaces has been used previously to assess the plastic zone and thereby the stress intensity experienced at the crack tip [40]. Withers [41] has shown that synchrotron x-ray diffraction measurements within steep stress gradients can result in significant peak broadening that might be misinterpreted as a result of plasticity.…”

Section: Discussionmentioning

confidence: 99%

Evolution of a laser shock peened residual stress field locally with foreign object damage and subsequent fatigue crack growth

2015

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Evolution of a laser shock peened residual stress field locally with foreign object damage and subsequent fatigue crack growth. Acta Materialia, http://dx.doi.org/10.1016/j.actamat.2014.09.032 conditions. The ballistic FOD impacts were introduced by impacting a cube edge at an angle of head-on (0 degrees) to the leading edge. The residual stress distributions have been mapped by synchrotron X-ray diffraction prior to cracking and subsequent to short (~1 mm) and long (up to 6 mm) crack growth. 2The results suggest that the local residual stress field is highly stable even to the growth of relatively long cracks.

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“…From the X-ray measurements it is also possible to take another information related to the modification of the surface properties induced by shot peening [12]. This information comes from the width of the diffraction peak, taken at one half of the peak (FWHM), that is, an index of the grain distortion and of the dislocation density, thus being a parameter that locally identifies the hardening induced by shot peening.…”

Section: Experimental Analysis and Resultsmentioning

confidence: 99%

Influence of Shot Peening Process on Contact Fatigue Behavior of Gears

Pariente

Guagliano

2009

Materials and Manufacturing Processes

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Shot peening is a cold working process used to increase mechanical strength of metal parts under fatigue load. It introduces compressive residual stresses and surface hardening in the surface layers of metallic materials by the impact of a shot flow against the metallic surface under controlled conditions. Shot peening can be made by using different kinds of machines, the most common of which are the pneumatic and the centrifugal ones. This article shows how the kind of process used can influence the results of the treatment. Four groups of gears were peened using different peening machines (pneumatic and centrifugal). The measurement of residual stresses and hardness allowed to evidence the different effect of the shot peening process. Contact fatigue tests showed that contact fatigue life is influenced by the process selected and that the choice of the Almen Intensity should consider also the kind of machine used.

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X‐ray diffraction studies on fatigue crack plastic zones developed under plane strain state conditions

Cited by 17 publications

References 13 publications

X‐ray fractography of a diesel engine crankshaft

X‐ray fractography of a diesel engine crankshaft

Evolution of a laser shock peened residual stress field locally with foreign object damage and subsequent fatigue crack growth

Influence of Shot Peening Process on Contact Fatigue Behavior of Gears

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