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Abstract

An optical measurement method of radial displacement of a ring sample during its expansion with velocity of the order 172 m/s and estimation technique of plastic flow stress of a ring material on basis of the obtained experimental data are presented in the work. To measure the ring motion during the expansion process, the Phantom v12 digital high-speed camera was applied, whereas the specialized TEMA Automotive software was used to analyze the obtained movies. Application of the above-mentioned tools and the developed measuring procedure of the ring motion recording allowed to obtain reliable experimental data and calculation results of plastic flow stress of a copper ring with satisfactory accuracy.

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Authors and Affiliations

Jacek Janiszewski
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Abstract

As the duration of a rock burst is very short and the roadway is seriously damaged after the disaster, it is difficult to observe its characteristics. In order to obtain the dynamic characteristics of a rock burst, a modified uniaxial compression experiment, combined with a high-speed camera system is carried out and the process of a rock burst caused by a static load is simulated. Some significant results are obtained: 1) The velocity of ejected particles is between 2 m/s and 4 m/s. 2) The ratio of elastic energy to plastic energy is about five. 3) The duration from integrity to failure is between 20 ms and 40 ms. Furthermore, by analyzing the stress field in the sample with a numerical method and crack propagation model, the following conclusions can be made: 1) The kinetic energy of the ejected particles comes from the elastic energy released by itself. 2) The ratio of kinetic energy to elastic energy is between 6% and 15%. This can help understand the source and transfer of energy in a rock burst quantitatively.
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Bibliography

[1] F. Ren, C. Zhu, M. He, Moment Tensor Analysis of Acoustic Emissions for Cracking Mechanisms During Schist Strain Burst. Rock Mech. Rock Eng. 53, 1-2(2019). DOI: 10.1007/s00603-019-01897-3
[2] G . Su Y. Shi, X. Feng, J. Jiang, J. Zhang, Q. Jiang, True-Triaxial Experimental Study of the Evolutionary Features of the Acoustic Emissions and Sounds of Rockburst Processes. Rock Mech. Rock Eng. 51, 375-389 (2018). DOI: 10.1007/ s00603-017-1344-6
[3] F. Gong, Y. Luo, X. Li, X. Si, M. Tao, Experimental simulation investigation on rockburst induced by spalling failure in deep circular tunnels. Tunn. Undergr. Sp. Tech. 81, 413-427(2018). DOI: 10.1016/j.tust.2018.07.035
[4] S.H. Cho, Y. Ogata, K. Kaneko, A method for estimating the strength properties of a granitic rock subjected to dynamic loading. Int. J. Rock Mech. Min. 42 (4), 561-568(2005). DOI: 10.1016/j.ijrmms.2005.01.004
[5] J. Wang, H.D. Park, Comprehensive prediction of rockburst based on analysis of strain energy in rocks. Tunn. Undergr. Sp. Tech. 16 (1), 49-57(2001). DOI: 10.1016/S0886-7798(01)00030-X
[6] M.N. Bagde, V. Petorš, Fatigue properties of intact sandstone samples subjected to dynamic uniaxial cyclical loading. Int. J. Rock Mech. Min. Sci. 42 (2), 237-250(2005). DOI: 10.1016/j.ijrmms.2004.08.008
[7] M. Cai, H. Morioka, P.K. Kaiser, Y. Tasaka, H. Kurose, M. Minami, T. Maejima, Back-analysis of rock mass strength parameters using AE monitoring data. Int. J. Rock Mech. Min. 44 (4), 538-549(2007). DOI: 10.1016/j.ijrmms.2006.09.012
[8] K. Du, M. Tao, X. Li, J. Zhou, Experimental Study of Slabbing and Rockburst Induced by True-Triaxial Unloading and Local Dynamic Disturbance. Rock Mech. Rock Eng. 49 (9), 3437-3453(2016). DOI: 10.1007/s00603-016-0990-4
[9] R . Simon, PhD thesis, Analysis of fault-slip mechanisms in hard rock mining, McGill University, Quebec/Montreal, Canada (1999).
[10] N .G. Cook, The failure of rock. Int. J. Rock Mech. Min. 2 (4), 389-403(1965). DOI: 10.1016/0148-9062(65)90004-5
[11] P.N. Calder, D. Madsen, High frequency precursor analysis prior to a rockburst. Int. J. Rock Mech. Min. Geomech. Abstr.26, 3-4 (1989). DOI: 10.1016/0148-9062(89)92469-8
[12] Z.T. Bieniawski, Mechanism of brittle fracture of rock: Part II—experimental studies. Int. J. Rock Mech. Min. 4 (4), 407-423 (1967). DOI: 10.1016/0148-9062(67)90031-9
[13] S.P. Singh, Burst energy release index. Rock Mech. Rock Eng. 21 (2), 149-155 (1988). DOI: 10.1007/BF01043119
[14] A. Kidybiński, Bursting liability indices of coal. Int. J. Rock Mech. Min. Sci. 18 (4), 295-304 (1981). DOI: 10.1016/0148-9062(81)91194-3
[15] A. Tajduś, M. Cala, K. Tajduś, Seismicity and Rock Burst Hazard Assessment in Fault Zones: a Case Study. Arch. Min. Sci. 63 (3), 747-765 (2018). DOI: 10.24425/123695
[16] W.D. Ortlepp, T.R. Stacey, Rockburst mechanisms in tunnels and shafts. Tunn. Undergr. Sp. Tech. 9 (1), 59-65 (1994). DOI: 10.1016/0886-7798(94)90010-8
[17] H . Marcak, Seismicity in mines due to roof layer bending. Arch. Min. Sci. 57 (1), 229-250 (2012). DOI: 10.2478/v10267-012-0016-3
[18] T.J. Williams, C.J. Wideman, D.F. Scott, Case history of a slip-type rockburst. Pure Appl. Geophys. 139, 627-637 (1992). DOI: 10.1007/BF00879955
[19] A.A. Griffith, VI. The phenomena of rupture and flow in solids. Phil. Trans. Math. Phys. Eng. Sci. 221 (582-593), 163-198 (1921). DOI: 10.1098/rsta.1921.0006
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Authors and Affiliations

Weiyu Zheng
1 2

  1. China University of Mining & Technology (Beijing), School of Energy and Mining Engineering, China
  2. State Key Laboratory of Coal Mining and Clean Utilization, China
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Abstract

The paper presents a proposition of the theoretical-experimental method of determination of power losses in the transversely vibrating rubber V-belt of continuously variable transmission. The article comprises the results of experimental tests conducted on a special test stand with a complete scooter drivetrain powered by a small two-stroke internal combustion engine. Such a configuration allows ensuring real CVT working conditions. A high-speed camera was used for the contactless measurement of belt vibrations and time-lapse image analysis was performed in dedicated software. An axially moving Euler–Bernoulli beam was assumed as the mathematical model. Longitudinal vibrations and nonlinear effects were omitted. Additionally, it was assumed that the belt material behaves according to the Kelvin–Voigt rheological model. Analysis of the damped free vibrations of the cantilever beam, made of the belt segment, allowed to determine the equivalent bending damping coefficient. The CVT power losses, due to bending in the rubber transmission belt, were obtained for the fixed working conditions after numerical calculations. The proposed methodology is a new approach in this research area, which allows to obtain results impossible to achieve with other measurement methods.
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Authors and Affiliations

Waldemar Łatas
1
ORCID: ORCID
Adam Kot
2
ORCID: ORCID

  1. Department of Applied Mechanics and Biomechanics, Faculty of Mechanical Engineering, Cracow University of Technology, Poland
  2. Department of Automotive Vehicles, Faculty of Mechanical Engineering, Cracow University of Technology, Poland

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