Lateral stiffness and deflection of vertical ropes with application to mine shaft hoisting

2008 ◽  
Vol 5 (1) ◽  
pp. 59-70 ◽  
Author(s):  
M E Greenway
Keyword(s):  
Lateral Stiffness ◽  
Mine Shaft ◽  
Deflection Of Vertical

Electrochemical nucleation and growth of copper on iron and aluminum: A TEM study of industrial copper cementation

1978 ◽  
Vol 36 (1) ◽  
pp. 454-455
Author(s):  
L.E. Murr ◽  
V. Annamalai
Keyword(s):  
Metal Surface ◽  
Copper Deposit ◽  
Nucleation And Growth ◽  
16Th Century ◽  
Electrochemical Reactions ◽  
Mine Shaft ◽  
De Re ◽  
Copper Precipitation ◽  
Electrochemical Nucleation ◽  
Interesting System

Georgius Agricola in 1556 in his classical book, “De Re Metallica”, mentioned a strange water drawn from a mine shaft near Schmölnitz in Hungary that eroded iron and turned it into copper. This precipitation (or cementation) of copper on iron was employed as a commercial technique for producing copper at the Rio Tinto Mines in Spain in the 16th Century, and it continues today to account for as much as 15 percent of the copper produced by several U.S. copper companies.In addition to the Cu/Fe system, many other similar heterogeneous, electrochemical reactions can occur where ions from solution are reduced to metal on a more electropositive metal surface. In the case of copper precipitation from solution, aluminum is also an interesting system because of economic, environmental (ecological) and energy considerations. In studies of copper cementation on aluminum as an alternative to the historical Cu/Fe system, it was noticed that the two systems (Cu/Fe and Cu/Al) were kinetically very different, and that this difference was due in large part to differences in the structure of the residual, cement-copper deposit.

Uneven Wear of Vehicle Tires

1993 ◽  
Vol 21 (4) ◽  
pp. 202-219 ◽  
Author(s):  
M. H. Walters
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Techniques ◽  
Lateral Stiffness ◽  
General Increase ◽  
Element Analysis ◽  
The Past ◽  
Uneven Wear

Abstract Advances in tire construction have led to major increases in tire life over the past twenty years, mainly by increasing the lateral stiffness and thus reducing slip during cornering. However, this general increase in tire life has tended to highlight the problem of uneven wear. In the present paper, three new experimental techniques are described which have been developed to study treadwear distributions. These techniques are evaluated and their results compared with a finite element analysis. Taken together, they indicate some of the causes of uneven wear and may be used to identify tire design and service features which contribute to uneven wear.

Study on Rational Ratios of Lateral Stiffness for Masonry Building with Frame Structure at First Two Stories

2012 ◽  
Vol 174-177 ◽  
pp. 2012-2015
Author(s):  
Xiao Long Zhou ◽  
Ying Min Li ◽  
Lin Bo Song ◽  
Qian Tan
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Shear Wall ◽  
Calculation Model ◽  
Frame Structure ◽  
Wall Structure ◽  
Masonry Building ◽  
Lateral Stiffness ◽  
Stiffness Ratio ◽  
Lateral Stiffness Ratio

There are two typical seismic damage characteristics to the masonry building with frame shear wall structure at first two stories, and the lateral stiffness ratio of the third storey to the second storey is one of the key factors mostly affecting the seismic performance of this kind of building. However, some factors are not considered sufficiently in current Chinese seismic codes. According to the theory of performance-based seismic design, the seismic performance of this kind of structure is analyzed in this paper by taking time-history analysis on models which with different storey stiffness ratios. The results show that when the lateral stiffness ratio controlled in a reasonable range, the upper masonry deformation can be ensured in a range of elastic roughly, and the bottom frame can be guaranteed to have sufficient deformation and energy dissipation capacity. Finally, according to the seismic performance characteristics of masonry building with frame shear wall structure at first two stories, especially the characteristics under strong earthquakes, a method of simplified calculation model for the upper masonry is discussed in this paper.

Development and Modeling of a Highly-Adjustable Base Isolator Utilizing Magnetorheological Elastomer

2013 ◽  
Author(s):  
Yancheng Li ◽  
Jianchun Li
Keyword(s):  
Analytical Model ◽  
Seismic Isolation ◽  
Large Scale ◽  
Lateral Stiffness ◽  
Magnetorheological Elastomer ◽  
Isolation System ◽  
Vertical Loading ◽  
Base Isolator ◽  
Field Dependent ◽  
Dependent Property

This paper presents a recent research breakthrough on the development of a novel adaptive seismic isolation system as the quest for seismic protection for civil structures, utilizing the field-dependent property of the magnetorheological elastomer (MRE). A highly-adjustable MRE base isolator was developed as the key element to form smart seismic isolation system. The novel isolator contains unique laminated structure of steel and MRE layers, which enable its large-scale civil engineering applications, and a solenoid to provide sufficient and uniform magnetic field for energizing the field-dependent property of MR elastomers. With the controllable shear modulus/damping of the MR elastomer, the developed adaptive base isolator possesses a controllable lateral stiffness while maintaining adequate vertical loading capacity. Experimental results show that the prototypical MRE base isolator provides amazing increase of lateral stiffness up to 1630%. Such range of increase of the controllable stiffness of the base isolator makes it highly practical for developing new adaptive base isolation system utilizing either semi-active or smart passive controls. To facilitate the structural control development using the adaptive MRE base isolator, an analytical model was developed to stimulate its behaviors. Comparison between the analytical model and experimental data proves the effectiveness of such model in reproducing the behavior of MRE base isolator, including the observed strain stiffening effect.

scholarly journals Evaluation of Stiffness and Dynamic Properties of a Mine Shaft Steelwork Structure through In Situ Tests and Numerical Simulations

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 664
Author(s):  
Jacek Jakubowski ◽  
Przemysław Fiołek
Keyword(s):  
Numerical Simulations ◽  
Dynamic Properties ◽  
Vertical Motion ◽  
Load Test ◽  
Mode Shapes ◽  
Dynamic Amplification Factor ◽  
In Situ Tests ◽  
Mine Shaft ◽  
Numerical Investigations

A mine shaft steelwork is a three-dimensional frame that directs the vertical motion of conveyances in mine shafts. Here, we conduct field and numerical investigations on the stiffness and dynamic properties of these structures. Based on the design documentation of the shaft, materials data, and site inspection, the steelwork’s finite element model, featuring material and geometric non-linearities, was developed in Abaqus. Static load tests of steelwork were carried out in an underground mine shaft. Numerical simulations reflecting the load test conditions showed strong agreement with the in situ measurements. The validated numerical model was used to assess the dynamic characteristics of the structure. Dynamic linear and non-linear analyses delivered the natural frequencies, mode shapes, and structural response to dynamic loads. The current practices and regulations regarding shaft steelwork design and maintenance do not account for the stiffness of guide-to-bunton connections and disregard dynamic factors. Our experimental and numerical investigations show that these connections provide considerable stiffness, which leads to the redistribution and reduction in bending moments and increased stiffness of the construction. The results also show a high dynamic amplification factor. The omission of these features implicates an incorrect assessment of the design loads and can lead to over- or under-sized structures and ultimately to shortened design working life or failure.

Construction and operation of batching plants in difficult geological conditions of Upper Kama potash mines

2021 ◽  
pp. 51-56
Author(s):  
V. N. Aptukov ◽  
V. V. Tarasov ◽  
V. S. Pestrikova ◽  
O. V. Ivanov
Keyword(s):  
Crack Opening ◽  
Concrete Lining ◽  
Salt Deposit ◽  
Mine Shaft ◽  
Deformation And Fracture ◽  
Geological Conditions ◽  
Negative Impacts ◽  
Long Term Experience ◽  
Term Maintenance

Scenarios of the component arrangement of batching plants in the system of a vertical mine shaft are discussed. The features of operation of batching plants in vertical shafts of potash mines are identified. The actual recorded damages generated in the lining of batching plants in the course of their longterm operation in potash mines are described. The geomechanical researches aimed to determine vertical convergence in batching rooms of mine shafts, as well as for monitoring of crack opening and displacements in sidewalls in the batching chambers are presented. The major results of the full-scale geomechanical observations are reported, and the main causes of fractures in concrete and reinforced concrete lining at junctures of shafts and batching rooms and shaft bins are identified. The set of the engineering solutions implemented for the protection of lining in batching facilities during construction of mine shafts is described, and its efficiency is evaluated. The mathematical modeling is carried out to estimate various negative impacts on deformation and fracture of concrete lining in shafts with regard to the time factor. From the modeling results, the dominant cause of concrete lining damage in batching chambers and in mine shaft is found. Based on the accomplished research results and actual long-term experience of operation of mine shafts, the most favorable factors are determined for the best design choices in construction and long-term maintenance-free operation of batching plants in potash mines of the Upper Kama Potash–Magnesium Salt Deposit.

The Dynamic Characteristics of Rigid Frame Single-Rib Arch Bridge

2013 ◽  
Vol 368-370 ◽  
pp. 1426-1430
Author(s):  
Li Xiong Gu ◽  
Rong Hui Wang
Keyword(s):  
Dynamic Characteristics ◽  
Bending Strength ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
Bending Stiffness ◽  
Torsional Stiffness ◽  
Lateral Stiffness ◽  
Arch Bridge ◽  
Vertical Stiffness ◽  
Rigid Frame

In this paper, by establishing the finite element model to study the dynamic characteristics of rigid frame single-rib arch bridge. By respectively changing structural parameters of the span ratios, and the compressive stiffness of arch, and the bending stiffness of arch, and the bending stiffness of bridge girder, and the layout of boom to find out the regularity of the structure on lateral stiffness, and vertical stiffness, and torsional stiffness as well as dynamic properties, it come out the results of that lateral stiffness of the structure is weaker, and increasing the span ratios and the compressive strength of arch are conducive to the improvement of the overall stiffness, and improving the bending strength of arch and layout of boom are less effect on the overall stiffness and mode shape.

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