Fracture toughness and damage development in limpet shells

O’Neill, Maeve; Cafiso, D.; Mala, Riccardo; Rosa, Guido La; Taylor, David

doi:10.1016/j.tafmec.2018.04.013

Cited by 10 publications

(4 citation statements)

References 22 publications

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“…Jiang et al [9] simulated series of direct shear tests on coplanar and noncoplanar jointed rocks using the PFC2D. e failure of joint will greatly affect the safety of rock mass [10][11][12][13][14]. Bolts are widely used in major projects such as steep slopes and tunnels as an important means of reinforcing the fractured rock masses [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Anchor Stress and Deformation of the Bolted Joint under Shearing

Lin

Zhu

Yang

et al. 2020

Advances in Civil Engineering

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Bolts are widely used in rock mass engineering, wherein the bolt support improves the safety and stability of the rock mass. To reveal the mechanical behavior of the bolt and failure mechanism of the bolted joint in the shearing process, a direct shear test was conducted by changing the state of grouting, number of bolt, and inclination angle of the bolt. The change in the axial force of the anchor in the shearing process was evaluated by conducting a strain gauge test, and the mechanical behavior of the bolt under the external force was studied. The results showed that under the same normal stress, the yield displacement of the bolt decreased and the stiffness of the joint gradually increased with increased number of bolts. At the same number of bolts, their yield displacement increased with increased normal stress. Analysis further revealed that grouting on the joint improved the force condition of the bolt, increased the yield displacement of the bolt, and coordinated the deformation of the grouting body and bolt, thereby improving the shear strength of the joint. Lastly, when the anchor angles differed, the axial pulling resistance of the anchor changed, and the yield displacement of the anchor with 45° inclination was <90°. The yield displacement of the bolt showed that the supporting effect of the bolt with a 45° inclination was better than that of the bolt with a 90° inclination.

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Section: Introductionmentioning

confidence: 99%

Anchor Stress and Deformation of the Bolted Joint under Shearing

Lin

Zhu

Yang

et al. 2020

Advances in Civil Engineering

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“…Geotechnical engineering reinforcement plays an important role in its stability and safety, especially for fractured rock mass and soft soil layer [1][2][3][4][5][6][7]. While drilling and punching piles for mud-retaining walls in sand areas, there are problems such as muddy ground, stress relaxation, sediment, and disturbance of bearing end resistance so that the pile-end resistance and pile side friction resistance are significantly reduced [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Diffusion Law of Post‐Grouting Slurry in Sandy Soil

Yang

Cheng

Chen

2019

Advances in Civil Engineering

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In order to study the diffusion law of grouting slurry in sand areas, the grouting of cement slurry in sand was analyzed by the indoor grouting test under different water-cement ratios, grouting pressures, grouting amounts, and soil qualities, and the law of the post-grouting slurry is obtained. The results show that the grouting method is affected by the grouting pressure, water-cement ratio, grouting amount, and soil quality. Under the same grouting pressure, the diffusion modes of different water-cement ratio grouts in sands with different permeability coefficients, which are mainly manifested as osmotic diffusion, are basically the same; under the same water-cement ratio, when the grouting pressure is relatively small, the diffusion of modes of slurry is mainly osmotic in sand. The diffusion radius of cement slurry in sand has a good power function relationship with grouting pressure, water-cement ratio, permeability coefficient, and grouting amount. And, the empirical function model of slurry diffusion radius is proposed by regression analysis. The research results provide a certain theoretical and experimental reference for post-grouting in sandy areas.

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“…This would be a very interesting subject for future work. Additionally, these results could be used to create characteristic finite-element models, similar to those produced by our group [19] to model crack propagation through the shells. This would allow greater insight into how stresses are dispersed throughout the shell at the time of impact.…”

Section: Discussionmentioning

confidence: 99%

Repair and remodelling in the shells of the limpetPatella vulgata

O’Neill

Mala

Cafiso

et al. 2018

J. R. Soc. Interface.

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Limpets and other molluscs rely on shells to protect them from physical damage, predation, dehydration, etc. If the shell becomes damaged, this may significantly impair its function. In this work, experiments were carried out to investigate the effect of damage on the strength of shells of the common limpet () and their ability to repair this damage effectively. Shells were damaged in three ways: (i) low-energy impacts; (ii) abrasion of the outer layer; and (iii) creation of a small hole in the apex of the shell. Shells were left to repair for several time periods (0, 10, 30 and 60 days). The mechanical strength was evaluated by impacting the shells with a weight dropped from a known height. The damage reduced the strength (defined as impact energy to failure) by 50-70% depending on damage type. After 60 days, limpets in all three groups had repaired their shells significantly, bringing their strength to 79-91% of the control value (in each case, samples were statistically indistinguishable from their control counterparts). Measurements of the thickness of the shell at the apex suggest that the main effect of low-energy impact and abrasion is reduction in thickness, which correlates linearly with the impact energy needed for failure. The method of repair is believed to be by the growth of fresh shell material on the inside of the shell, though we could not identify this new material specifically. Even after 60 days, the shells were still statistically thinner than the controls. Consequently, there may be some other strengthening mechanism at work. This work has demonstrated the remarkable ability of limpets to detect the mechanical weakening of their shells caused by relatively subtle forms of damage and to take appropriate action to restore shell strength.

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Fracture toughness and damage development in limpet shells

Cited by 10 publications

References 22 publications

Anchor Stress and Deformation of the Bolted Joint under Shearing

Anchor Stress and Deformation of the Bolted Joint under Shearing

Experimental Study on Diffusion Law of Post‐Grouting Slurry in Sandy Soil

Repair and remodelling in the shells of the limpetPatella vulgata

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