Stress intensity factor determination from isochromatic fringe patterns—A review

Østervig, Carl B.

doi:10.1016/0013-7944(87)90040-3

Cited by 14 publications

(4 citation statements)

References 101 publications

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“…Can we estimate inherent strength by experiment? Such questions have inspired development of the str-POM method, 48,49 which is schematically depicted in Figure 3, based on photoelastic effects for polymers, 94 which have been studied 95 for many materials.…”

Section: Plastics (Glassy and Semicrystalline Polymers)mentioning

confidence: 99%

“…Can we estimate inherent strength by experiment? Such questions have inspired development of the str -POM method, , which is schematically depicted in Figure , based on photoelastic effects for polymers, which have been studied for many materials. The recent str -POM measurements show , that (a) stress saturation occurs upon approach to crack tip, as depicted in Figure b and (b) σ tip(F) = σ F(inh) is comparable to nominal strength σ b , thus supporting the speculation that plastics are flaw tolerant, contrary to the prevailing viewpoint (Kinloch, 2013)..…”

Section: Plastics (Glassy and Semicrystalline Polymers)mentioning

confidence: 99%

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Fracture Behavior of Polymers in Plastic and Elastomeric States

Wang,

Fan,

Gupta

et al. 2024

Macromolecules

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Our recent studies departed from the conventional description of polymer fracture behavior while maintaining consistency with the principles of material mechanics including linear elastic fracture mechanics (LEFM). In traditional fracture mechanics of brittle materials, crack resistance is quantified in terms of toughness G c , which represents the critical energy release per unit fracture surface area. This perspective suggests that high G c involved high energy dissipation. A new perspective has surfaced, proposing a fundamental yet underexplored, seemingly universal fracture mechanism and explaining the origin of high G c within an alternative framework. According to this view, for unfilled plastics and elastomers, f racture initiates when local tensile stress surpasses the polymer's f racture strength σ F(inh) , and high toughness is a consequence of high fracture strength. Remarkably, for polymers in both plastic and elastomeric states, their inherent strength σ F(inh) appears to be of a comparable magnitude to the nominal tensile strength σ b . Spatial−temporal resolved polarized optical microscopic (str-POM) measurements have started to provide insight into the fracture mechanism and unveil a concealed length scale (P) representing the size of a stress saturation zone at the crack tip. The two-parameter theoretical framework shows (a) toughness of brittle plastics increases quadratically with its strength σ F(inh) and linearly with P and (b) elastomers exhibit significantly greater toughness and higher tensile strength at lower temperatures due to the increased stability of covalent bonds given the lower thermal energy and plausible frictional effect on bond vibration frequency. Embracing this emerging paradigm where we recognize polymer strength to be time-dependent, we anticipate new advancements in polymer design and a clearer understanding of the fracture behavior of polymeric materials.

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Section: Plastics (Glassy and Semicrystalline Polymers)mentioning

confidence: 99%

Section: Plastics (Glassy and Semicrystalline Polymers)mentioning

confidence: 99%

Fracture Behavior of Polymers in Plastic and Elastomeric States

Wang,

Fan,

Gupta

et al. 2024

Macromolecules

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“…Photoelasticity has been widely used by various authors to evaluate the SIFs of cracked homogeneous [18][19][20][21] and bimaterial components subjected to static [22][23][24][25] or dynamic loading [41,42] because, as has been shown in numerous applications [43], the isochromatic fringes are very sensitive to the parameters that govern a singular stress field. Unfortunately, all the methods proposed in the literature do not exploit the full field data available from modern automated photoelasticity techniques [44] and do not allow the user a previous evaluation of the SDZ extension.…”

Section: Experimental Analysis Of Sifs By Photoelasticity: State Of Tmentioning

confidence: 99%

Use of automated photoelasticity to determine stress intensity factors of bimaterial joints

Zuccarello

Ferrante

2005

The Journal of Strain Analysis for Engineering Design

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A new systematic experimental procedure has been developed to obtain the stress intensity factors governing the singular stress field that occurs near the intersection between the interface and free edges of bimaterial joints. A preliminary theoretical study of the singular stress field is carried out by the well-known Airy stress function method. The obtained stress laws are properly combined with the basic law of photoelasticity in order to define a procedure that permits the zone dominated by the singularity to be located and the stress intensity factors (SIFs) to be computed on the basis of full field data provided from automated photoelasticity. In particular, a systematic error analysis is used to determine the model zone where the experimental data have to be collected in order to obtain accurate SIF evaluation. As an example, the proposed method is applied to determine the SIFs of various aluminium/ PSM-1 specimens under different external loading conditions using Fourier transform photoelasticity. The experimental results have been compared to those obtained by an independent procedure, based on a boundary element approach, in order to validate the accuracy of the proposed procedure.

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“…The strong intensification of the stress fields around inhomogeneities, flaws, defects, cracks and voids inside a solid represents a fundamental aspect in mechanical design, being strictly connected to the material strength and its failure. For this reason, stress intensification has been the subject of an intensive research activity, encompassing analytical [1][2][3][4][5], numerical [6][7][8][9][10][11][12] and experimental [13][14][15][16][17][18][19] approaches.…”

Section: Introductionmentioning

confidence: 99%

Torsion of elastic solids with sparse voids parallel to the twist axis

Shahzad

Corso

2019

Mathematics and Mechanics of Solids

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With the purpose of investigating a linear elastic solid containing a dilute distribution of cylindrical and prismatic holes parallel to the torsion axis, the full-field solution for an infinite elastic plane containing a single void and subject to torsion is derived. The obtained solution is exploited to derive the analytic expressions for the Stress Concentration Factor (SCF) related to the presence of an elliptical hole, for the Stress Intensity Factor (SIF) for hypocycloidal-shaped hole and star-shaped cracks, and for the Notch Stress Intensity Factor (NSIF) for star-shaped polygons. Special sets of the void location are obtained for which peculiar mechanical behaviours are displayed, such as the stress annihilation at some points along the boundary of elliptical voids and the stress singularity removal at the cusps/points of hypocycloidal shaped/isotoxal star-shaped polygonal voids. By means of finite element simulations it is finally shown that the presented closed-form expressions for the stress intensification provide reliable predictions even for finite domain realizations and, in particular, the infinite-plane solution remains highly accurate when the size of smooth and non-smooth external boundary is greater than twice and five times the void dimension, respectively. Under these geometrical conditions, the derived analytical expressions represent a valid 'guide tool' in mechanical design.

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Stress intensity factor determination from isochromatic fringe patterns—A review

Cited by 14 publications

References 101 publications

Fracture Behavior of Polymers in Plastic and Elastomeric States

Fracture Behavior of Polymers in Plastic and Elastomeric States

Use of automated photoelasticity to determine stress intensity factors of bimaterial joints

Torsion of elastic solids with sparse voids parallel to the twist axis

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