Crack repair using an elastic filler

Fowkes, Neville; Freitas, J. A. Teixeira de; Stacey, Richard

doi:10.1016/j.jmps.2008.06.001

Cited by 17 publications

(12 citation statements)

References 12 publications

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“…When the elastic modulus of the coating approaches that of the glass substrate, the stress intensity factor asymptotically diminishes to zero, indicating that the crack is completely healed and repaired by the coating. The reason for the increase in the strength of coated glass is the forming of elastic bridging of two surfaces of the crack by the coating . The higher the elastic modulus of the coating is, the stronger the stiffness, and the more obvious the bridging effect is.…”

Section: Resultsmentioning

confidence: 99%

“…The reason for the increase in the strength of coated glass is the forming of elastic bridging of two surfaces of the crack by the coating. 38,39 The higher the elastic modulus of the coating is, the stronger the stiffness, and the more obvious the bridging effect is. In the experiment, the elastic modulus of the coating increases by increasing the curing temperature.…”

Section: Elastic Modulusmentioning

confidence: 99%

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Strengthening mechanism of cover glass by Sol‐Gel SiO₂ coating

Zhou

Wen

et al. 2019

Int J of Appl Glass Sci

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Strengthening is a huge challenge of ultrathin cover glass in mobile electronic devices. In this paper, a transparent sol‐gel silica coating has been sprayed on the surface of chemically strengthened cover glass, and three different coatings (identified as thickness/curing temperature: 3 μm/80°C, 5 μm/80°C, and 3 μm/180°C) have been prepared. Characterized by four‐point bending experiment, the strengthening effects of three coatings, representing by the increases of strength of the coated glass, are 47 MPa, 98 MPa, and 58 MPa for 3 μm/80°C, 5 μm/80°C, and 3 μm/180°C, respectively. Based on finite element simulation and experimental data of four‐point bending, the influence of four parameters of surface coating (elastic modulus, residual stress, filling ratio, and thickness) on glass strengthening has been investigated. Simulation analysis shows that the increase of elastic modulus, residual stress, and filling ratio of the SiO2 coating facilitates the increase of bending strength of cover glass, and the coating thickness has less influence on the glass strength. However, the experimental results demonstrate that the coating thickness has a significant impact on the strength of glass: when the layer thickness of sample cured at 80°C increases from 3μm to 5μm, the bending strength of glass can improve by 51MPa. Since greater coating thickness induces greater filling ratio, which is the main contributor to the strengthening effect of increased coating thickness, so, elastic modulus, residual stress, and filling ratio of the coating are the three key factors of the cover glass strengthening.

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Section: Resultsmentioning

confidence: 99%

Section: Elastic Modulusmentioning

confidence: 99%

Strengthening mechanism of cover glass by Sol‐Gel SiO₂ coating

Zhou

Wen

et al. 2019

Int J of Appl Glass Sci

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“…ey demonstrated that the modulus of elasticity of a cracked rock after injecting materials into its pores was equal to the uncracked rock. According to their theoretical results, Fowkes et al found that filling materials with low modulus of elasticity can effectively prevent the propagation of cracks and further rock failure [29]. Pan and Xiong conducted compressive and bending tests on the repaired rock and expressed that the addition of filling materials with comparable strength to the matrix can remarkably enhance the rock's integrity and reduce further fracturing [30].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Properties of a Polymer-Modified Material for Thin Spray-On Liners in Mine Roadways

Chen

Jiang

et al. 2020

Advances in Materials Science and Engineering

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In order to adapt to dry and wet environment in mine roadways and improve the performance of sealing materials under different environmental conditions, this study selected the materials based on their ability to spray and found that the materials with a viscosity of 1500–6000 MPa·s can achieve a balance between performance of spray and wall-hanging performance. Next, by selecting high-elastic polyacrylate emulsion and ordinary Portland cement as the film-forming agent and gel, respectively, mix proportion factors of the nonreactive thin spray-on liner (TSL) were analyzed by using the Taguchi method. Moreover, fluidity, setting time, sealing properties, compressive strength, bending strength, and bonding strength of those materials were measured. It was disclosed that addition of an appropriate amount of polyacrylate emulsion can enhance the effects of fibers. By observing the morphologies of the materials’ bonding surfaces and comparing the factors influencing bonding strength between both dry and wet walls, it was uncovered that the adhesive property of cement-based sealing materials was mainly affected by the water-cement ratio. Eventually, bonding strength and sealing properties were selected as primary optimization indexes, while setting time, bending strength, and compressive strength were selected as secondary optimization indexes. The appropriate proportions of two types of TSLs for dry and wet walls were (W/C = 50%; P/C = 6%; F/C = 1%; T/C = 0.2%) and (W/C = 45%; P/C = 6%; F/C = 1%; T/C = 0.4%), respectively. A prepared TSL can be used for filling rock fractures in mine roadways. In addition, TSL exhibited a great performance for dry and wet walls under different environmental conditions. The present study may provide an insightful guidance and reference for the investigation of TSL sealing materials applied in the mine roadways.

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“…The sprayed on TSL's are thought to penetrate and effectively repair surface cracks so that the fracturing required for rock detachment doesn't occur. Theoretical results show that the effect of the sprayed on material (providing it penetrates the crack) is to change the stress singularity at crack tips, and almost complete repair (no stress singularity) occurs even with elastically weak TSL's, see Fowkes and de Freitas (2008). Another advantage of TSL's is that they are inexpensive to apply.…”

Section: Introductionmentioning

confidence: 99%

Rockbursts mud and plastic

Fowkes¹

2011

Chan, F., Marinova, D. And Anderssen, R.S. (Eds) MODSIM2011, 19th International Congress on Modelling and Simulation.

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The gold mines in South Africa are the deepest in the world and rockbursts (including tunnel collapse) are a common occurrence, endangering life, causing damage to rock support structures and resulting in costly delays. Rockbursts are violent outbursts of broken rock and concrete in tunnels primarily caused by the accumulation of elastic strain energy in the tunnel walls but often triggered by seismic events. During a rockburst hundreds of tonnes of pulverized rock may be expelled into openings accompanied by a sudden sharp sound, an air blast, and a dense cloud of dust. The air blast itself can propagate kilometers through the tunnel system and be of sufficient strength to overturn vehicles.Conventional wisdom is that rockburst activity is much less likely in tunnels with water or mud on the floor. We examine mechanisms that may explain such reduced activity using simple mechanistic models. The investigations suggest that lubrication effects due to the presence of water within cracks could inhibit, and in some cases prevent, the expulsion of rock lumps from tunnel walls. The effect of the water in a crack is to produce a suction force proportional to µω/h α 0 with α ≈ 5, where h 0 is the crack thickness, ω is the frequency of the impacting earthquake wave and µ the shear viscosity of water. Thus strong suction forces occur for small cracks and high frequency impacting earthquakes. These forces may cause an almost detached rock lump to remain attached, or detach if the eruption time span is large enough and the attachment to the walls is weak enough. Estimates suggest that both scenarios are possible in practice. These results also suggest that coating the tunnel walls with moisture containing semi liquid pastes or spray on plastic materials may be effective for tunnel wall stabilization.

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Crack repair using an elastic filler

Cited by 17 publications

References 12 publications

Strengthening mechanism of cover glass by Sol‐Gel SiO₂ coating

Strengthening mechanism of cover glass by Sol‐Gel SiO₂ coating

Synthesis and Properties of a Polymer-Modified Material for Thin Spray-On Liners in Mine Roadways

Rockbursts mud and plastic

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Crack repair using an elastic filler

Cited by 17 publications

References 12 publications

Strengthening mechanism of cover glass by Sol‐Gel SiO2 coating

Strengthening mechanism of cover glass by Sol‐Gel SiO2 coating

Synthesis and Properties of a Polymer-Modified Material for Thin Spray-On Liners in Mine Roadways

Rockbursts mud and plastic

Contact Info

Product

Resources

About

Strengthening mechanism of cover glass by Sol‐Gel SiO₂ coating

Strengthening mechanism of cover glass by Sol‐Gel SiO₂ coating