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Operation of vertical transport installations is based on adjustable electrical drive systems which must ensure the technical conditions regarding the variation in time of the speed, the current of the main motors and the accelerations at start and brake phases. Electric drives are part of the fast process of automation equipment. In the case of a vertical transport installation, speed is the characteristic which has to be controlled in command phase, while the dependent factor is the tachograph. The adjustment determines the dependence of the quantity in the process – based on a default law - with respect to the independent quantities and also to the process dependents, thus reducing the influence of the perturbations to the process. There are different ways to define the stability of an automatic system. The balance survey / analysis also approaches the determination of the functions of variation in time of the main actuation motor current and speed (main motor rpm), at the moments of starting the vertical transport installation, and the study of the variation in time of the speed in the case of a load shock. To perform calculations needed for stability assessment and draw all the diagrams a Turbo C 2.0 program was written by the authors.

The bucket wheel excavator (BWE) is a complex continuous digging machine, used to excavate material using a layout of buckets installed on a rotor (bucket wheel), and at the same time, using the conveyor system installed on its boom, transferring this material to the main conveyor. The bucket wheel is the operating equipment, and it rotates in the vertical plane and performs (with the boom) a pivoting movement in the horizontal plane and an ascendant – descendent movement in the vertical plane. The paper presents a new grafo-numeric method of determination of the operation power of the BWE rotor, using computer simulation in SolidWorks. The aim of using virtual models for the analysis of the operation of some components of the BWE is to reduce the specific energy consumption during cutting while maintaining the installed operation power of the rotor, to increase the excavation capacity and to improve the cutting – loading system.

An important feature of the drums of mine shearers, is the material loading capacity onto the armored face conveyor. This characteristic is influenced by both the shape of the vane and the pitch of the helical vane. Thus, the pitch of the helical vane can be either constant or variable. This variable pitch can also have two variants. The first one is with an axial pitch when there is a progressive increase in the pitch of the helical vane towards the conveyor direction, thus resulting in a productivity increase of 15-20% compared to drums with a constant pitch. This constructive variant does not ensure the placement of the cutting picks to achieve a balanced working regime. The second constructive variant is with a radial pitch when the helical vane profile has a variable height along the generating curve. This constructive variant is considered more advantageous, ensuring a more rational placement of the cutting pitch by maintaining a constant axial pitch. In this paper a modeling is proposed for the drum of the CA-1 longwall shearer with variable axial-radial pitch. [ABSTRACT FROM AUTHOR]

In the paper, we addressed the simulation and numerical modeling of deformation under static loading of wire ropes used in mine hoisting installations. We presented the main types of extraction vessels (cages and skips) commonly used in the mining industry, as well as the fastening devices to the hoisting rope (DLC). A review was conducted on the primary structural models of traction cables equipping mine hoisting machines. As one of the critical assessments performed on cables in mining extraction is done at maximum static load, we constructed a virtual model of a tension testing stand for a hoisting cable using SOLIDWORKS®. Essentially, we created a virtual device in the form of an assembly consisting of multiple parts, establishing geometric connections between them. Additionally, we highlighted the cable's path over the core of the fastening device. The actual tension test was performed through a simulation under static loading of a 500 mm section of the cable. We determined the von Misses stress and overall deformations of the cable section. [ABSTRACT FROM AUTHOR]

The shield of the SMA-2 utilizes a quadrilateral mechanism with a corner cylinder generating a lemniscate. The synthesis of the quadrilateral mechanism, its geometric and kinematic analysis in correlation with the geometry and kinematics of the entire support, raises challenging analytical issues. For this reason, in the present work, we have theoretically and practically analyzed the geometry and kinematics of the mechanism, demonstrating the utility of using computer software for modeling and simulation in addressing these problems. [ABSTRACT FROM AUTHOR]

The interactive method presented in the paper, allows the calculation of maximum efficiency indicators (organic yields) of the processing and operational control of the actual processing process. It also allows the correlation of the technological parameters with the economic ones in order to properly capitalize on the products obtained by processing a material (raw coal or sterile resulted from coal preparation) containing solid fuel fractions. Using the interactive system, one can pre-determine the optimal mixture of material to be processed and have different characteristics. The interactive method consists of three C programs that allow: the selection of the mixture of solid material to be processed, by tracing the abacuses and determining the theoretical weight extractions, depending on the desired quality of the concentrates; calculation of the organic processing yields; estimating the processing results, using the Fournol method, taking into account the performance of the processing equipment used and the density of separation between the products. [ABSTRACT FROM AUTHOR]

In the field of mechanical engineering, FEA (Finite Element Analysis) is widely used to solve structural, vibration and thermal problems, and its versatility and numerical efficiency have imposed the finite element analysis method on the engineering analysis software market over time, while other methods have become niche applications. The finite element method is mainly used in the activity of simulating and modeling some phenomena in geo-mechanical engineering. In this sense, the simulation of the crushing phenomenon of rocks used in construction, such as marble, is of particular importance. Finding suitable methods for simulating this phenomenon can shorten the design period of rock coring tools, and regarding the actual crushing phenomenon, by validating the results obtained in the simulation process, preliminary conclusions can be drawn, so that laboratory tests are only needed in the final phase of a research. Starting from the characteristics of a core drill, a model of a marble specimen was created in the SOLIDWORKS application, a model that I later subjected to the compression request simulation using the Irazu application. The obtained results will be compared to the actual results gathered in laboratory tests. [ABSTRACT FROM AUTHOR]

The compression load of straight bars, for which the cross-sections are smaller compared to their length, causes a phenomenon of bending along the longitudinal axis. Upon reaching a certain level, called the critical level of the stresses, the bending deformations begin to increase beyond the bearing limit of the bar. It yields instantly, due to an unstable elastic deformation state, although the material's resistance limit has not been exceeded. The irreversibility of the phenomenon is dangerous especially for the railway tracks and is not fully mastered by calculation methods. They can eventually establish the level of the critical demand, which has values specific to each rail configuration. It is accepted that for loads lower than this level, buckling of the respective rail does not occur. The longitudinal tension in the railway tracks occurs due to the expansion caused by their heating under the action of the sun's rays, but also due to the friction between the rails and the train wheels. This paper proposes the realization of a study model of the buckling of the railway tracks. This model is represented by an assembly, built in the SOLIDWORKS application for which a Buckling simulation was made. The imposition of two distinct temperatures on the rails and crossties is the source of the model's request. The increase in the temperature of the component parts of the assembly causes their expansion, so implicitly the appearance of some longitudinal deforming forces, specific to the buckling phenomenon. [ABSTRACT FROM AUTHOR]

Mine winding systems are a complex set of machines, devices, and mechanisms, which work together both to transport useful mineral substances or tailings from the mine to the surface or to other horizons, as well as to transport personnel, materials, and equipment, from surface to underground. The mine winding systems consists of the actual mine hoisting machine, the head-frame, cables (ropes), conveyances, auxiliary equipment, control and safety devices. The braking system can operate as service brake or safety brake. The service brake acts on the rope wheel to achieve the required tachogram, while the safety braking occurs independently of the operator's will, in the following situations: the lack of power supply, the decrease in the pressure of the hydraulic fluid, over winding of the conveyances, exceeding the maximum permitted extraction speed. A functional condition imposed on the brakes of a mine windings system is to ensure the immobilization of the conveyances after a safety braking. This paper proposes a study of the stresses and deformations to which the drive wheel drum of a single-rope friction mine hoist is subjected to, when it must keep the conveyances immobilized following a safety braking. To solve the mentioned problem, a virtual model of the drum of such an installation was created in SOLIDWORKS. [ABSTRACT FROM AUTHOR]

The movement of a vehicle is determined by the use of the energy transmitted to the wheels, from the engine through the chain: gearbox - differential. Traction force, resistance forces and inertial forces determine the character of the vehicle's movement. In this paper, I approached the study of air resistance to the forward movement of a vehicle using the calculation technique. In this sense, we used the SOLIDWORKS® application with the help of which, using the model of a truck, we studied its aerodynamic behaviour in a virtual tunnel. We considered that a frontal air flow with a speed of 25 m/s (90 km/h) acts on the vehicle. The variation of the air speed in the direction of travel of the vehicle was determined. The obtained results were presented in the form of flow trajectories and in the form of sections corresponding to the reference planes. We also determined the variation of vorticity, as a quantity specific to fluid mechanics in order to highlight the intensity of circulation or the speed of air rotation, from the rear area of the vehicle. [ABSTRACT FROM AUTHOR]