Simulation of Laboratory Tests of Steel Arch Support

Horyl, Petr; Šňupárek, Richard; Maršálek, Pavel; Pacześniowski, Krzysztof

doi:10.1515/amsc-2017-0012

Cited by 11 publications

(7 citation statements)

References 5 publications

(4 reference statements)

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“…In recent times, computer simulation became popular to investigate YFS behavior although the problem of friction and reciprocal sliding of the frame segment remains unsolved [6,[27][28][29][30][31][32]. Horyl et al [28] simulated by finite element method (FEM) vibration of YFS due to its dynamic loading.…”

Section: Analysis Of the Yfs Resistance Oscillation Dynamicsmentioning

confidence: 99%

“…This simulation was carried out on a symmetrical half of the profile, and reciprocal sliding of the segments was quasi-static because the researchers did not mention dynamic oscillation of the YFS resistance. In [30], Horyl et al used FEM model that accounted for nonlinear behavior of the frame. However, the Authors managed to trace the first peak of the frame resistance only in limited range of deformation 60-70 mm.…”

Section: Analysis Of the Yfs Resistance Oscillation Dynamicsmentioning

confidence: 99%

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Dissipative structure suppression as a way to increase the sustainable improvement of the frame support bearing capacity

Nazimko¹,

Zakharova²,

Merzlikin

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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Introduction. A yield frame support is a basic means of providing the underground roadways’ stability in the deep mines operating in the hard ground control condition when the ratio of the ground pressure to the unconfined strength of surrounding rock mass exceeds 0.33. The operators adjust the nominal bearing capacity of the frames at 0.55 of their maximum or peak resistance Fmax because the frames operate in a dry friction mode spontaneously generating oscillation, which causes variation of the resistance in the range from 0.1 up to 0.9 of Fmax . Aim/tasks. We intended to reduce the dynamic oscillation of the support resistance that allows for increasing their bearing capacity. Methodology. We used a computer simulation by FLA3D model, indoor testing of the frames, and actual measurements in an underground coal mine. Results. We revealed a specific behavior of the frame support that reduced the limit of the bearing capacity by 45%. During yielding, the frames generate dissipative structures (DS) that become apparent due to the dynamic nature of stick-slip friction following the yielding process. We demonstrated that DS control and especially its suppression provides a sustainable increase in the frame bearing capacity. Conclusions. Improvement of the yield frames design and especially their clamps are the prospective way to control DS and provide sustainable enhancement of the frame bearing capacity.

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Section: Analysis Of the Yfs Resistance Oscillation Dynamicsmentioning

confidence: 99%

Section: Analysis Of the Yfs Resistance Oscillation Dynamicsmentioning

confidence: 99%

Dissipative structure suppression as a way to increase the sustainable improvement of the frame support bearing capacity

Nazimko¹,

Zakharova²,

Merzlikin

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

View full text Add to dashboard Cite

show abstract

“…In underground mines, dynamically capable ground support systems are one of the most reliable options [1]. A steel arch yielding support of roadways is a widely used support structure in European mines [2] and worldwide. For example, in German coal mines, 65 % of roadways are supported by yieldable steel arches and the percentage is still growing [3].…”

Section: Introductionmentioning

confidence: 99%

Single-Step Heat Treatment for the Restoration of Mechanical Properties of Cold-Strained Mining Support Steel 31Mn4

Lojen

Mayer²,

Bončina

et al. 2020

SV-JME

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The steel 31Mn4+QT630 is used frequently for mining support arches. The supports are cold strained, first during service, and again by re-rolling prior to reinstallation, which results in strain hardening and a loss of ductility. Consequently, many of the rerolled arch-segments are not suitable for reinstallation because their mechanical properties are inadequate. The objective of this work was to assess the feasibility of restoration of the required mechanical properties by means of a cost-efficient single step heat treatment. Specimens were cold deformed to different degrees in the range 0 % to 45 % to establish the relation between the degree of cold deformation and the hardness. Differently strain hardened specimens were subjected to subcritical annealing at temperatures 450 °C to 700 °C in the duration 0.5 h to 8 h to determine a suitable time-temperature combinations. Microstructures and mechanical properties were investigated of as-received, cold strained and recrystallized specimens. Tests performed were optical microscopy, scanning electron microscopy, tensile tests, hardness measurements and Charpy impact tests. Elongation at break of the as-received material was below the requirements of the applicable standard, and its microstructure contained significant fractions of pre-eutectoid ferrite and pearlite. Upon cold straining, hardness increased by approximately 2 HV per 1 % of strain. After one-hour recrystallization at 600 °C to 620 °C, the microstructure consisted of a ferritic matrix containing evenly dispersed globular carbide particles. The original ductility was restored, while the elongation, yield strength, and hardness were higher than in the as-received condition. These results confirmed that it is feasible to restore the original mechanical properties of heavily strained profiles with an adequate single-step heat treatment. Furthermore, they indicated that it should be possible to recover the required properties of inhomogeneously strained material with the same set of well optimized heat treatment parameters. Consequently, it should be possible to increase the reuse rate and to decrease the costs for new support arches significantly.

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“…The article presents the results of tests conducted on a steel arch support in the form of the sliding joints [6,7,8] of an ŁP/V29 (ŁP-type yielding steel arch support frame constructed from a V29 section), which is commonly employed in the Polish hard coal mines. Tests of elements of threaded bolts with trapezoidal threads over the entire rod length were conducted as well.…”

Section: Introductionmentioning

confidence: 99%

Tests of steel arch and rock bolt support resistance to static and dynamic loading induced by suspended monorail transportation

Pytlik

2019

Studia Geotechnica Et Mechanica

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At present, the suspended monorail systems constitute a very common means of transportation in the Polish hard coal mines. The main advantages of the suspended monorail include the independence of the route from the working floor surface irregularities and the possibility to transport cargo of significant mass and size.The masses and dimensions of machines and devices transported via monorail have increased considerably in recent times. This particularly concerns the transport of longwall system elements. In Poland, the maximum speed of suspended monorail travel is 2 m/s. Due to the fact that preparations are currently underway to increase the maximum speed above 2 m/s, it is necessary to inspect what influence it will have on work safety and mining support stability.Current operational experience and tests have shown that dynamic loads induced by the suspended monorail transportation have a significant influence on the roadway support stability, working protection durability and on the monorail operators. This is particularly true during the emergency braking of a suspended monorail by means of a braking trolley, where the overloads reach 3g.Bench tests of the selected steel arch and rock bolt support elements utilised in the Polish hard coal mines were conducted in order to determine the resistance of steel arch and rock bolt supports to static and dynamic loads.The article presents the results of the tests conducted on a steel arch support in the form of the sliding joints of an ŁP/V29 yielding roadway support, which is commonly employed in the Polish hard coal mines. Tests of elements of the threaded bolts with trapezoidal threads over the entire rod length were conducted as well.The conducted strength tests of steel arch and rock bolt support elements under static and dynamic loading have shown that dynamic loading has decisive influence on the support’s retaining of its stability. Support element stability decreases along with the increase of the impact velocity. This concerns both the steel arch support and the rock bolt support.

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Simulation of Laboratory Tests of Steel Arch Support

Cited by 11 publications

References 5 publications

Dissipative structure suppression as a way to increase the sustainable improvement of the frame support bearing capacity

Dissipative structure suppression as a way to increase the sustainable improvement of the frame support bearing capacity

Single-Step Heat Treatment for the Restoration of Mechanical Properties of Cold-Strained Mining Support Steel 31Mn4

Tests of steel arch and rock bolt support resistance to static and dynamic loading induced by suspended monorail transportation

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