Analysis of influence of circular hole on stress state of plate in pure bending condition

The task of this paper is determining the zone of influence of a circular hole on the stress state of a homogeneous isotropic plate in pure bending condition. For solving the problem, the complex variable method was used which allows the complete analytical determination of the stresses at every point of the plate, and particularly on the contour of the circular hole. The analytical expressions for stresses in the plate of infinite dimensions were the basis for deriving a mathematical formulation which defines the zone as a function of diameter of the hole, inside which there is influence of the hole on the stress state of the plate. Obtained results are verified with FEM using the ANSYS software package whereby the input data for spatial discretization and mesh generation are not previously adjusted but was used a mesh that is generated automatically by the program.

Speed control of high power multiple drive belt conveyors

Belt conveyors play a very important role in the continuous transport o f bulk and piece material, especially in the mining industry. However, the use o f belt conveyors results in high electricity consumption. A reduction in the power consumption can be achieved by adjusting the speed o f the belt conveyor to match the material flow. However, inappropriate and frequent speed changes can cause serious damage to the conveyor elements. This paper presents a procedure for adjusting the belt conveyor speed to match the profile o f the material on the belt, as well as a detailed procedure for determining the time needed to accelerate/decelerate the belt conveyor. The research was performed on an actual 640 m long belt conveyor used for transport o f overburden at the surface mine Drmno (Serbia). The simulation results show that the speed regulation is completely justified because the conveyor operated at speeds lower than nominal throughout the testing.

The influence of different type of aggregate, fly ash and fiber-reinforced polymer on splitting resistance in pretensioned concrete railroad ties

This research evaluates the influence of the different types of concrete mixture, using a shallow type of indentation of wire, having the different edge distance and compressive strength of concrete on splitting resistance in pretensioned concrete railroad sleepers. The investigated compressive strength of concrete was 4500psi. The research was experimental, and the part of this research was formally adapted in Arema StandardsforRailwayEngineering Chapter 30 section 4.2.4.

Analysis of elevators dynamic parameters with solution of summary data acquisition during experimental research

Modelling of the dynamic behaviour of elevators with high lifting velocities (contemporary elevators in building construction and mine elevators) is a complex task and an important step in the design process and creating conditions for safe and reliable exploitation of these machines. Due to high heights and lifting velocities, the standard procedures for dynamic exploitation are not adequate. With the purpose of identifying the basic parameters of the dynamic model (stiffness and damping), a unique method was applied, based on experimental measures for a concrete elevator. Due to the verification of this procedure, the experiment was conducted on a mine elevator in RTB Bor, Serbia. Simulations of the dynamic behaviour of an empty and loaded cage are presented using the obtained computational-experimental results

Analysis of centrifugal compressor testing capabilities

The work shows examining of the centrifugal compressor for which there are no technical conditions by which the compressor manufacturer defines the form and important characteristics of the measuring installation. In the absence of the necessary data, a table for testing of centrifugal compressors was designed, where the pipeline measures and other details are freely defined in accordance with the available possibilities.

Influence of the traction force and the speed of movement on the strength characteristics of the locomotive axles

The article presents the dependencies obtained when researching the load on the locomotive axles, depending on the traction force and the speed of movement of the locomotive. The traction characteristic of the locomotive is the relationship between the traction force achieved by the traction motors and the speed of movement, and it is different under different driving conditions. Different modes of operation of locomotive axles are considered. A simulation of the axles' behaviour has been developed. The strength and deformation characteristics of the locomotive axles under different loading modes are calculated. A comparative analysis of the strength characteristics of locomotives with different classes of transmission mechanisms has been made

Some aspects of the implementation of actions plans for noise prevention and reduction in urban areas

Following the analysis of noise maps for road, rail and industrial traffic on Lden and Ln as well as the corresponding conflict maps, action plans were prepared to prevent and reduce noise in the mentioned areas of the urban environment. They set out the measures to be taken, the completion dates and the number of people benefiting from the noise reduction. Measures to reduce urban noise have also been established for the long-term strategy. These were performed with an application to the Timișoara city. Subsequently, the administrative bodies of the municipality proceeded to implement the measures provided in the action plans. The paper refers to some considerations on their implementation highlighting the resulting effects

Design and computer simulation of automatically controlled hydromechanical system for looped wedge wire screen elements fabrication

The article presents a design of mechatronic system used for the production of wire elements used in looped wedge wire screen manufacturing. Details related to the design of the hydromechanical subsystem, the control subsystem, as well as the simulation of the operation process of the entire system are presented

Basis for the design of drive-in and drive-through racking

Drive-in and drive-through accumulation racking systems are recommended for great amounts of goods with few various units. According to the "First In, Last Out" - FILO and "First-In, First-Out" - FIFO principle, the palletized load unit are stored into deep tunnels accessible by forklift trucks for handling operations. This allows exploiting as much room as possible and eliminating the aisles traditionally required for manipulating purposes. This paper provides basic information on the requirements, design and use of drive-in and drive-through racking systems in accordance with current regulations and standards. Minimum required clearances and tolerances due to all influencing parameters for manually operated systems are discussed.

Analysis of the main girder of the double-beam bridge crane with two trolleys

In this research, the problem of calculating the necessary static quantities of the main girder with the box crosssection of the double-beam bridge crane with two trolleys were analyzed. The aim is to determine the critical position on the girder due to the action of all loads in the vertical plane, as a function of input parameters, and to obtain expressions for calculating deflections in the vertical and horizontal planes, as well as bending moments in these planes, ie maximum (total) stress in the girder. Verification of the results was carried out in the SAP2000 software package, with proved a quite good correlation between the results obtained, for the proposed method of the calculation model of the box-girder, in the mentioned software package. The goal of this research is primarily to show how the application of the SAP2000 software package in an easy, fast and simple way can perform the dimensioning and design of this type of carrying structures, taking into account important static conditions that must be satisfied. By applying the proposed modelling method and using a certain module in the mentioned software package, the designer easily achieves the preliminary geometric values of the girder in the initial design phase, where he can completely rely on the obtained results. Also, all geometric quantities necessary for further phases in the design and calculation are obtained. Guidelines are given on how to prepare a calculation model in this software package for these types of carrying structures, as well as recommendations related to the design of these types of carrying structures made of S355 material.