An Experimental Study of Cutting Performances of Worn Picks

Doğruöz, Cihan; Bölükbaşı, Naci; Rostami, Jamal; Acar, Cemil

doi:10.1007/s00603-015-0734-x

Cited by 28 publications

(12 citation statements)

References 8 publications

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“…In carbonates, the size of cuttings ranges from 1 to 10 mm (0.04-0.4 in.) long depending on drilling conditions (Archie, 1952;Dogruoz et al, 2016); therefore, cuttings are approximately three orders of magnitude larger than pores. However, cuttings impose an inherent bias because they break preferentially along more porous and weaker planes; therefore, predicted permeabilities are lower-bound estimates of the formation permeability.…”

Section: Porosity and Specific Surfacementioning

confidence: 99%

Carbonate rocks: Matrix permeability estimation

Cardona

Santamarina

2020

Bulletin

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Carbonate rocks store half of the world's proven oil reserves. Genesis and postdepositional diagenetic processes define the porous network topology and the matrix permeability. This study compiles a database of porosity, specific surface, mercury porosimetry, and permeability values extracted from published sources and complements the database through a focused experimental study. Specific surface and porosity combine to estimate the pore size (D sur). Permeability versus D sur data cluster along a single trend with a slope of 2 in a log-log scale, which is in agreement with the Kozeny-Carman model. Discordant data points correspond to samples with dual porosity or broad pore-size distributions with long tails, where flow channels along larger interconnected pores. Indeed, the detailed analysis of all the porosimetry data in the database shows that permeability correlates best with the pore size D80, that is, the 80th percentile in pore-size distributions. Once again, the best fit is a power function in terms of (D80) 2 , analogous to Kozeny-Carman. The prediction uncertainty using D80 is one order of magnitude and has the same degree of uncertainty as more complex models and analyses. This observation suggests an irreducible uncertainty of one order of magnitude in permeability estimation from index properties such as porosity, mercury porosimetry, and specific surface probably resulting from specimen preparation effects, inherent physical differences in permeation versus invasion, and difficulties in data interpretation. These estimates of permeability are most valuable when specimens are limited to small sizes, such as cuttings.

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Section: Porosity and Specific Surfacementioning

confidence: 99%

Carbonate rocks: Matrix permeability estimation

Cardona

Santamarina

2020

Bulletin

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“…In addition, the size of the wear flat is assumed to be much smaller than the cutting depth and cutting width. For a badly worn chisel pick, the CEIT model needs improvement because the friction between the chisel pick and rock will increase with the increasing size of the wear flat [28,64]. Finally, the current form of the CEIT model is intended for unrelieved cutting conditions and is not suitable for relieved cutting conditions.…”

Section: Advantages and Limitations Of The Ceit Modelmentioning

confidence: 99%

An Analytical Model for Rock Cutting with a Chisel Pick of the Cutter Suction Dredger

Ouyang

Yang

Chen

et al. 2020

JMSE

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Cutter suction dredgers are important pieces of rock excavation equipment in port and waterway construction. It is valuable but difficult to properly estimate the cutting force on the chisel pick of the cutter suction dredger. In this paper, an analytical model, called the crushed zone expansion induced tensile failure model (CEIT model), is proposed for rock cutting with a chisel pick in order to predict the peak cutting force (Fc) more accurately. First, a review of the existing models for rock cutting with a chisel pick is presented. Next, based on the tensile breakage theory, cavity expansion theory and some hypotheses, the mathematical formula of the CEIT model is obtained. Different from that in the previous models, the effect of the rock on both sides of the chisel pick on Fc, defined as the sidewall effect is considered in the CEIT model. Then, the predicted Fc by the CEIT model is compared with the predicted Fc by existing theoretical models and experimental results to check the validity of the CEIT model. The results show that the CEIT model can well capture the relationships of Fc to the cutting parameters, including cutting width, cutting depth, and rake angle, and can predict the experimental results much better than the existing models. Finally, the sidewall effect and its influence factors according to the CEIT model are discussed.

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“…Conical picks work usually under high impact and stress conditions, resulting in frequent failure. The failure modes include premature wear, carbide tip drop off, fracture, and normal wear [1][2][3][4][5][6][7]. In order to understand the cutting properties of a pick, researchers have carried out substantial experimental work on pick cutting force prediction.…”

Section: Introductionmentioning

confidence: 99%

“…Full-scale cutting tests in different types of sedimentary rocks, with bits having various degrees of wear, have been conducted to evaluate the influence of bit wear on cutting forces and specific energy. Studies have examined the relationship of the amount of wear represented by the size of wear flats at the tip of bits, cutting forces, and specific energy [5]. Liu also investigated the influence of pick cutting types, structures, and working angle parameters on pick wear, and the effect of wear on the pick cutting performance, by using an experimental apparatus to cut coal rock [6].…”

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confidence: 99%

A Stress Analysis of a Conical Pick by Establishing a 3D ES-FEM Model and Using Experimental Measured Forces

2019

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This paper presents a procedure for an accurate and reliable stress analysis in a conical pick used in mining operations, aiming to improve their wear resistance. This is achieved by (1) establishment of a three-dimensional (3D) edge-based smoothed finite element method (ES-FEM), and algorithms of creating the smoothing domain for accurate solution in terms of stress and strain distributions; and (2) use of experimentally measured actual forces using a full-scale rotary cutting machine. In our 3D ES-FEM model, the physical domain for the pick is first discredited using linear triangular elements that can be generated easily for complicated geometries. The smoothing domains are then constructed based on edges of these elements in an automated fashion. In order to create the smoothing domains for the smoothed strain computation in the ES-FEM, an algorithm is presented for establishing connection between nodes, edges, faces, and elements. Each smoothing domain is bounded by a set of enclosed line-segments, besides, leading to a connectivity list for later effective computation. To show the effectiveness and accuracy of the strain energy and the displacement solution of ES-FEM, based on the actually measured forces from the laboratory rock cutting tests with a single pick, a comparison study is carried out against the standard finite element method (FEM). It can be concluded that ES-FEM has a higher convergence in energy norm and better accuracy than FEM using the same mesh from the comparison results. The 3D ES-FEM model solves the problem of the lower solution accuracy, caused by the poor quality of mesh, by using the standard FEM in solving the stress distribution of mining machinery parts, such as picks, and offers accurate and reliable solutions that are critical for improving the wear resistance of the pick for the mining industry.Experimental studies were performed to obtain the cutting performance parameters of conical picks, such as the pick force and wear influenced by cutting parameters and rock properties. Full-scale cutting tests in different types of sedimentary rocks, with bits having various degrees of wear, have been conducted to evaluate the influence of bit wear on cutting forces and specific energy. Studies have examined the relationship of the amount of wear represented by the size of wear flats at the tip of bits, cutting forces, and specific energy [5]. Liu also investigated the influence of pick cutting types, structures, and working angle parameters on pick wear, and the effect of wear on the pick cutting performance, by using an experimental apparatus to cut coal rock [6]. Bilgin et al. [8] carried out full-scale linear cutting tests, with different cutting depths and cut spacing, to study the conical pick performance on 22 different rock specimens, having compressive strength varying from 10 to 170 MPa. They found that the pick force and specific energy are positively correlated with rock properties, especially the uniaxial compressive strength and Brazilian tensile strength. Dewangan et a...

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An Experimental Study of Cutting Performances of Worn Picks

Cited by 28 publications

References 8 publications

Carbonate rocks: Matrix permeability estimation

Carbonate rocks: Matrix permeability estimation

An Analytical Model for Rock Cutting with a Chisel Pick of the Cutter Suction Dredger

A Stress Analysis of a Conical Pick by Establishing a 3D ES-FEM Model and Using Experimental Measured Forces

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