Theoretical and experimental investigation of brittle fracture in V-notched PMMA specimens under compressive loading

Ayatollahi, M.R.; Torabi, A.R.; Firoozabadi, Mohammad

doi:10.1016/j.engfracmech.2015.01.005

Cited by 39 publications

(23 citation statements)

References 65 publications

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“…a represents when the loading angle β increases beyond β II ,

Y_{I}^{V}

values become negative, which implies that the sharp V‐notch would be under compressive loading and hence tends to be closed under the applied force P . Therefore, the proposed SVR specimen can also be employed for compressive mixed mode fracture tests on V‐notches, which have been recently under focus of some researchers …”

Section: Fe Resultsmentioning

confidence: 99%

The role of first non‐singular stress terms in mixed mode brittle fracture of V‐notched components: an experimental study

Dehghany

Googarchin

Aliha

2016

Fatigue Fract Eng Mat Struct

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This paper investigates the effects of the first non‐singular stress terms on the fracture assessment of sharp V‐notches under mixed mode loading. First, numerical studies have been performed on a fracture test configuration called single V‐notched ring (SVR) specimen. Then, the notch stress intensity factors as well as the coefficients of the first non‐singular stress terms, which are vital parameters in brittle fracture of V‐notched components, were calculated via a finite element over‐deterministic algorithm for a wide range of loading and geometry conditions. The obtained results demonstrate that the SVR specimen is able to provide a complete range of mode mixities from pure mode I to pure mode II loading conditions. The numerical results, next, have been converted to dimensionless parameters and are illustrated in several graphs. Indeed, these graphs can be easily employed by the engineers for rapid calculation of the corresponding notch stress intensity factors and the coefficients of the first non‐singular stress terms in the SVR specimen. The obtained fracture parameters are then submitted to the maximum tangential stress criterion to assess the effects of the first non‐singular terms on fracture behaviour of the specimen. Finally, an experimental study has been performed on the SVR specimen made of Nayriz Marble rock for two notch angles with a complete range of mode mixities. The obtained experimental data confirm the significant role of the first non‐singular stress terms. In fact, these results show that considering only the singular stress terms may induce an average error of 38% in the predicted fracture loads, which can be decreased to about 12% just by adding the contribution of the first non‐singular terms to the maximum tangential stress criterion.

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“…a represents when the loading angle β increases beyond β II ,

Y_{I}^{V}

Section: Fe Resultsmentioning

confidence: 99%

The role of first non‐singular stress terms in mixed mode brittle fracture of V‐notched components: an experimental study

Dehghany

Googarchin

Aliha

2016

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

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“…In contrast, it slowly decreased in static severing. However, the loading rate produced little influence on maximum loading force in low and high loading rate when the workpiece was thermoset epoxy resin [ 14 ]. When the microgroove-apex radius was larger than the critical value of 40–50 μm, the severing force was not dominated by the microgroove-apex radius and the loading rate.…”

Section: Resultsmentioning

confidence: 99%

“…The linear elastic stress was also used to derive two brittle fracture criteria such as mean stress (MS) and point stress (PS) criteria [ 12 ]. Moreover, these criteria were used to predict compressive notch fracture toughness [ 13 , 14 ]. The minimum fracture loading of a U-notches plate was introduced by means of MS and PS criteria [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Study on Micro-Crack Induced Precision Severing of Quartz Glass Chips

2018

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It is difficult to cut hard and brittle quartz glass chips. Hence, a method involving micro-crack-induced severing along a non-crack microgroove-apex by controlling the loading rate is proposed. The objective is to realize the rapid and precision severing of the hardest quartz glass in chip materials. Firstly, micro-grinding was employed to machine smooth microgrooves of 398–565 μm in depth; then the severing force was modelled by the microgroove shape and size; finally, the severing performance of a 4-mm thick substrate was investigated experimentally. It is shown that the crack propagation occurred at the same time from the microgroove-apex and the loading point during 0.5 ms in micro-crack-induced severing. The severing efficiency is dominated by the severing time rather than the crack propagation time. When the loading rate is less than 20–60 mm/min, the dynamic severing is transferred to static severing. With increasing microgroove-apex radius, the severing force decreases to the critical severing force of about 160–180 N in the static severing, but it increases to the critical severing force in the dynamic severing. The static severing force and time are about two times and about nine times larger than the dynamic ones, respectively, but the static severing form error of 16.3 μm/mm and surface roughness of 19.7 nm are less. It is confirmed that the ideal static severing forces are identical to the experimental results. As a result, the static severing is controllable for the accurate and smooth separation of quartz glass chips in 4 s and less.

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“…PMMA is often chosen for the study of crack-defect interaction mechanisms instead of actual geological materials because of its homogeneity, high mechanical strength, high transparency, low density, and easy casting. The wave speed and dynamic fracture behaviour of PMMA are very similar to certain relevant brittle solids at room temperature, and so allows for some read-across to the study of fracturing problems in geological materials under both static and dynamic loading conditions (Ayatollahi et al 2015;Huang et al 2009;Xu et al 2005;. ) established a dynamic caustics testing system to study the fracture of PMMA under blast loading, as PMMA was assumed to some extent o have similarities with rock.…”

Section: Causticsmentioning

confidence: 99%

High-Speed Photography and Digital Optical Measurement Techniques for Geomaterials: Fundamentals and Applications

et al. 2017

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Geomaterials (i.e., rock, sand, soil and concrete) are increasingly being encountered and used in extreme environments, in terms of the pressure magnitude and the loading rate. Advancing the understanding of the mechanical response of materials to impact loading relies heavily on having suitable high-speed diagnostics. One such diagnostic is high-speed photography, which combined with a variety of digital optical measurement techniques can provide detailed insights into phenomena including fracture, impact, fragmentation and penetration in geological materials. This review begins with a brief history of high-speed imaging. Section 2 discusses of the current state-of-the-art of high-speed cameras, which includes a comparison between Charge-Coupled Device (CCD) and Complementary Metal-Oxide-Semiconductor (CMOS) sensors. The application of high-speed photography to geomechanical experiments is summarized in Section 3. Section 4 is concerned with digital optical measurement techniques including photoelastic coating, Moiré, caustics, holographic interferometry (HI), particle image velocimetry (PIV), digital image correlation (DIC) and infrared thermography (IRT), in combination with highspeed photography to capture transient phenomena. The last section provides a brief summary and discussion of future directions in the field.

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Theoretical and experimental investigation of brittle fracture in V-notched PMMA specimens under compressive loading

Cited by 39 publications

References 65 publications

The role of first non‐singular stress terms in mixed mode brittle fracture of V‐notched components: an experimental study

The role of first non‐singular stress terms in mixed mode brittle fracture of V‐notched components: an experimental study

Study on Micro-Crack Induced Precision Severing of Quartz Glass Chips

High-Speed Photography and Digital Optical Measurement Techniques for Geomaterials: Fundamentals and Applications

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