Modern Applied Fracture Mechanics

Coates, Cameron; Sooklal, Valmiki

doi:10.1201/9781003052050

Cited by 3 publications

(7 citation statements)

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“…The faster you peel, the higher the force required; this is the crack drag effect that was mentioned by Rivlin in 1944, leading to a characteristic peel energy versus crack speed curve, as shown in Figures 1, 3,5, and 7 [20]. Such characteristic curves do not exist in Fracture Mechanics texts where plastic flow is the dominant phenomenon [1,2,11].…”

Section: Importance Of Crack Speedmentioning

confidence: 95%

“…Fracture Mechanics has a much-documented background based in Griffith's experimental results on fracture of pressurised precracked glass tubes [1,2,11]. He showed failure stress falling for longer pre-cracks, as failure stress σ changed with crack length c in the (corrected) Griffith equation…”

Section: Historical Backgroundmentioning

confidence: 99%

“…A vital difficulty of traditional fracture mechanics texts is that they do not consider that the force pulling atoms apart must increase as the crack velocity rises [1,2,11]. Typically, when glass under tensile stress breaks, the crack accelerates as the force drops, which is the opposite of the expected behaviour.We need to show that solid atoms separating under controlled conditions must give crack velocity rising with force.…”

Section: Importance Of Crack Speedmentioning

confidence: 99%

“…The crack therefore travels at constant speed, unlike the accelerating Griffith crack. Moreover, the stress field around the crack tip is irrelevant and there is no need for a 'stress intensity factor' which had been defined to fit the energy balance result for the Griffith crack geometry [1,2,11]. Clearly, this peel crack is driven only by the tensile strain energy, has nothing to do with shear or peel strength, and should be called tensile delamination, as defined for adhesive lap joints [22].…”

Section: Peel Crack Driven By Stored Elastic Strain Energymentioning

confidence: 99%

“…Metals displaying plastic flow and concrete crumbling around a crack do not heal like smooth soft polymers and therefore cannot normally be treated with an equilibrium theory of fracture. So, Fracture Mechanics has drifted away from the fundamental ideas of atoms and equilibrium, which are not emphasised in the Wikipedia page, nor in recent books [9][10][11]. By contrast, this paper views peel cracks as solid state chemical reactions between rubber and substrate molecules, where the dynamic molecular interactions are vital in both peeling and healing.…”

Section: Introductionmentioning

confidence: 99%

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Peeling Reveals Problems of Strength Standards for Brittle Materials

Kendall¹

2023

J Eng App Sci Technol

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Peeling creates a ubiquitous crack used regularly to open plastic packaging. Such peel cracks have been utilised for centuries, especially in separating cellulose fibres, yet these peeling cracks are not usually mentioned in fracture texts [1,2]. In this paper, theories and experiments show that peel cracks have unique properties quite different from the tensile-test cracks generally used to define and standardize strength of materials. Peeling is the easiest fracture test at the lowest force with the simplest theory describing constant speed cracks that are readily observed. It differs markedly from the catastrophic tensile cracks seen in many brittle materials such as concrete and glass, that accelerate rapidly at high force. The problem is that strength in peeling is not consistent with strength in tension. There is a large size effect in peeling where strength drops for larger sample size. Therefore, standards need to be modified. This paper describes peeling observations in several crack test geometries, fitting the energy theory of thermodynamic crack equilibrium, contrary to the stress/strength criteria that dominate existing brittle-material standards, which need correction.

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Section: Importance Of Crack Speedmentioning

confidence: 95%

Section: Historical Backgroundmentioning

confidence: 99%

Section: Importance Of Crack Speedmentioning

confidence: 99%

Section: Peel Crack Driven By Stored Elastic Strain Energymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Peeling Reveals Problems of Strength Standards for Brittle Materials

Kendall¹

2023

J Eng App Sci Technol

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Fracture Mechanics Testing

Gdoutos,

Konsta-Gdoutos

2024

Solid Mechanics and Its Applications

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The Numerical Analysis of Force and Comparison of Pulse Magnet and Electromagnetic Forming Coil

Li,

Tang,

et al. 2023

Materials

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As an important energy conversion component in electromagnetic-forming technology, the coil is subjected to great internal stress and is easy to break. The geometric structure and winding process of the forming coil draw on the research results of pulsed magnets. However, the two use conditions are different. It is very important to clarify the force difference between the two for the design of the forming coil. In this paper, the numerical model of an aluminum alloy (AA1060-O) is established, and the difference in force between the pulse magnet and forming coil with the same size in time and space under different working conditions is analyzed. A two-dimensional fully coupled finite element model consisting of circuit, magnetic field, and solid mechanics is established and used to determine the key parts of the coil force. It is found that the von Mises stress of the forming coil is greater than that of the pulsed magnet under the same circuit parameters and geometric structure. In the electromagnetic forming of the tube, the glass fiber is subjected to a large stress. In addition, the stress of glass fiber under the condition of tube necking is about 2 times that of pulsed magnet. When the voltage is increased, the failure of the middle part of the glass fiber causes the coil to break. In the electromagnetic forming of the sheet, the coil skeleton is subjected to large stress, and its upper end failure causes the coil to break. Therefore, new design ideas for forming coils under different working conditions are proposed.

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Modern Applied Fracture Mechanics

Cited by 3 publications

References 0 publications

Peeling Reveals Problems of Strength Standards for Brittle Materials

Peeling Reveals Problems of Strength Standards for Brittle Materials

Fracture Mechanics Testing

The Numerical Analysis of Force and Comparison of Pulse Magnet and Electromagnetic Forming Coil

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