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Machniak L.,AGH University of Science and Technology | Koziol W.,Institute of Mechanized Construction and Rock Mining
Archives of Mining Sciences | Year: 2017

A new hypothesis concerning a process of the mining solid rocks using bucket wheel excavators (BWE). Destroying of the rock mass structure is a result of breaking and not, as so far accepted, of cutting. This approach excludes, for the description of solid rock workability using bucket wheel excavators, used classifications based on individual linear or surface resistances of cutting. The possibility of a replacement mechanism for determining of the workability by bucket wheel excavators using rippers was assumed. On this basis, an innovative method for assessing the workability of solid rocks was developed, which is a combination of an derived empirical energy relationship LSE of breaking by tractor rippers from a compressive strength, a seismic wave velocity, a density of solid rock, and the modified classification of workability by bucket wheel excavators according to Bulukbasi (1991). The proposed method allows for multi-parameter assessment of the workability class based on the parameters that are independent variables in the specified dependencies. © 2017 Archives of Mining Sciences 2017.


Smiszek-Lindert W.,Institute of Mechanized Construction and Rock Mining | Michta A.,University of Silesia | Tyl A.,University of Silesia | Malecki G.,University of Silesia | And 2 more authors.
Journal of the Serbian Chemical Society | Year: 2015

The X-ray structure, theoretical calculation, Hirshfeld surfaces analysis, IR and Raman spectra of fluoranthene and acenaphthene were reported. Acenaphthene crystallizes in the orthorhombic crystal system and space group P21ma, with crystal parameters a = 7.2053(9) Å, b = 13.9800(15) Å, c = = 8.2638 (8) Å, Z = 4 and V = 832.41(16) Å3. In turn, the grown crystals of fluoranthene are in the monoclinic system with space group P21/n. The unit cell parameters are a = 18.3490(2) Å, b = 6.2273(5) Å, c = 19.8610(2) Å, ß = = 109.787(13)°, Z = 8 and the unit cell volume is 2135.50(4) Å3. Theoretical calculations of isolated molecules of the title compounds were performed using DFT at the B3LYP level. The intermolecular interactions in the crystal structure, for both the title polycyclic aromatic hydrocarbons were analyzed using the Hirshfeld surfaces computational method. © 2015 SCS.


Flakus H.T.,University of Silesia | Hachula B.,University of Silesia | Turek E.,University of Silesia | Michta A.,University of Silesia | And 2 more authors.
Chemical Physics Letters | Year: 2015

This letter is devoted to the explanation of the differences between the IR spectral properties of hydrogen bond systems found in crystals of two isomeric thioamides, thioacetanilide (TACN) and N-methylthiobenzamide (NMTB). The magnitude of the temperature-dependent Davydov-splitting effects, the H/D isotopic 'self-organization' effects in the crystalline polarized IR spectra depend on the electronic properties of the two different associating molecular systems, which are affected by the methyl and phenyl substituent groups linked to the HNCS common structural fragments. © 2015 Elsevier B.V. All rights reserved.


Smiszek-Lindert W.,Institute of Mechanized Construction and Rock Mining | Chelmecka E.,Medical University of Silesia, Katowice | Chelmecka E.,University of Silesia | Dudzinska A.,Cracow University of Technology
Structural Chemistry | Year: 2016

The Hirshfeld surface analysis, theoretical calculation, and IR and Raman spectra of p-acetotoluidide and p-thioacetotoluidide were reported. Hirshfeld surfaces and fingerprint plot have been used for visualizing, exploring, and quantifying intermolecular interactions in the crystal lattice of the title compounds. The packing of the molecules in the crystal structure of p-acetotoluidide and p-thioacetotoluidide forms the chains of N–H···O and N–H···S hydrogen bonds, respectively. The close contacts are also dominated by H···H and H···C/C···H interactions. The analysis of Hirshfeld surface has been well correlated with the spectroscopic studies. Theoretical calculations of the title compounds’ isolated molecule have been carried out using DFT at the B3LYP level. © 2016 Springer Science+Business Media New York


Blachowski B.D.,Polish Institute of Fundamental Technological Research | Gutkowski W.,Institute of Mechanized Construction and Rock Mining | Wisniewski P.,Polish Institute of Fundamental Technological Research
COMPDYN 2015 - 5th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering | Year: 2015

The paper deals with a nonlinear analysis of a tall tower, with Circular Flange Bolted Connections (CFBC), in which friction and contact effects are taken into account. Due to these nonlinearities, a detailed dynamic model of the whole structure would lead to very complex computational problem, unable for practical solutions. To overcome these difficulties a reduced order model of CFBC is proposed. Such a model enables the simulation of the whole tower including nonlinearities in connections. The paper is illustrated with an example of model reduction and dynamic calculations for a contemporary telecommunication tower. The tower is assembled of 4 truss segments, of triangular cross section, interconnected with CFBCs. Finally, the influence of the number of modes, included in the reduced order model, on the accuracy and computational effect, is discussed.


Blachowski B.,Polish Institute of Fundamental Technological Research | Gutkowski W.,Institute of Mechanized Construction and Rock Mining
Engineering Structures | Year: 2016

The paper deals with non-linear analysis of a telecommunication tower with circular flange-bolted connections (CFBCs). They are composed of two flanges, welded to the structural tubes, and then connected together with pre-tensioned bolts. A rigorous FEM analysis is performed for finding the connection stiffness in two cases. One deals with all bolts undamaged and the second one with one or more bolts broken.The analysis, which includes contact and friction forces, shows that when joints are under tension, the bolts are not only subjected to axial forces, but also to bending moments due the prying effect. The value of stresses caused by bending depends strongly on the bolt pre-tension and flange thickness. Removing one of the six connection bolts significantly increases stresses in the remaining bolts. Knowing the behaviour of the connection, it is possible to study the behaviour of the whole structure. This is achieved by applying the multilevel substructuring approach. The first levels is related to the flanges and bolts, whereby the connection model is simplified, and compared with the rigorous one, the second level is related to the assembly of the whole tower.The paper is illustrated with several examples of connections of different thicknesses, and different bolt pre-tensions. The considered tower comes from a real design. © 2015 Elsevier Ltd.


Blachowski B.,Polish Institute of Fundamental Technological Research | Swiercz A.,Polish Institute of Fundamental Technological Research | Gutkiewicz P.,Polish Institute of Fundamental Technological Research | Szelazek J.,Polish Institute of Fundamental Technological Research | Gutkowski W.,Institute of Mechanized Construction and Rock Mining
Measurement: Journal of the International Measurement Confederation | Year: 2016

An experimental and analytical study of the relation between local defect, in a steel structure, and its higher frequencies and higher modes is discussed. The structure is a plane steel frame, assembled of beams, joined together with bolted connections. Removing some bolts from a given connection simulates the damage. In the experiment, an impulse force induced structural vibrations. Effects of vibrations were shown by data from gages, measuring accelerations with a high accuracy. From the data, it could be observed, that mode shapes, for the healthy and damaged structures didn't show any differences for low frequencies. Only modes around thirteen showed significant gap between picks of Frequency Response Functions, for healthy and damaged frame. Moreover, looking at mode shapes, it could be observed that structural configuration may have some influence on defects to be observable. This aspect is discussed in a separate section. The experiment performed on the whole structure allows finding the place where the defect is localized. However, it can't give detailed information on the defect itself, here defect of a bolt. For finding it, an ultrasonic measurement of pre-tensioning forces in bolts was applied. It allowed not only to determine stresses in the bolt, but also to verify, if in the process of assembling the structure was not pre-stressed. © 2016 Elsevier Ltd. All rights reserved.


Golos K.,Warsaw University of Technology | Jastrzebski M.,Institute of Mechanized Construction and Rock Mining
Solid State Phenomena | Year: 2016

In the paper an extended experimental study and numerical analysis of fatigue strength of aluminum alloy EN AW – 6063 welded thin-walled aluminum structural stair construction is presented. The FEM calculations were carried out. In analysis the concept of the weak link was applied. The critical thin-walled welded tread stairs node was selected and the concept was verified experimentally for two variants of cyclic loading. The effect of cyclic loading on crack initiation and propagation in the welds and residual strength was examined. It was observed the reduction in residual strength, i.e. 1.61% for the construction of thin-walled welded connection after 30 000 cycles, and about 6.19% after 100 000 cycles. © 2016 Trans Tech Publications, Switzerland.


Blachowski B.,Polish Academy of Sciences | Gutkowski W.,Institute of Mechanized Construction and Rock Mining
Bulletin of the Polish Academy of Sciences: Technical Sciences | Year: 2014

In this study, a relatively simple method of discrete structural optimization with dynamic loads is presented. It is based on a tree graph, representing discrete values of the structural weight. In practical design, the number of such values may be very large. This is because they are equal to the combination numbers, arising from numbers of structural members and prefabricated elements. The starting point of the method is the weight obtained from continuous optimization, which is assumed to be the lower bound of all possible discrete weights. Applying the graph, it is possible to find a set of weights close to the continuous solution. The smallest of these values, fulfilling constraints, is assumed to be the discrete minimum weight solution. Constraints can be imposed on stresses, displacements and accelerations. The short outline of the method is presented in Sec. 2. The idea of discrete structural optimization by means of graphs. The knowledge needed to apply the method is limited to the FEM and graph representation. The paper is illustrated with two examples. The first one deals with a transmission tower subjected to stochastic wind loading. The second one with a composite floor subjected to deterministic dynamic forces, coming from the synchronized crowd activities, like dance or aerobic.

Loading Institute of Mechanized Construction and Rock Mining collaborators
Loading Institute of Mechanized Construction and Rock Mining collaborators