The paper presents a review of the most important triaxial testing machines and triaxial specimens from literature. It also includes a finite element analysis of a triaxial specimen. The main feature that is studied refers to the geometry of the specimen so that it is obtained a state of stress as favourable as possible for the fracture to occur.
Machines. Technologies. Materials.
Vol. 9 (2015), Issue 12
Table of Contents
The color recorded in the image is not an inherent value of observed object, because it is also influenced by the illumination properties, as well as geometry and surfaces of neighboring objects. Numerous studies have developed and investigated image processing procedures in color sorting machines, where as not many of them have considered the influence of illumination on numerical values related to the colors. In this paper, parameters related to the color of corn have been examined. In each image, the corn has been illuminated by one of four different types of light sources. And different luminous intensities of each type of light source have been applied. The processing of obtained images has been performed in MATLAB, and parameters of images in RGB, CIE L*a*b* and HSV color space have been analyzed. Further descriptive statistics analysis has been performed by IBM SPSS. The variations of parameters with the change of light intensity, showed no statistical significance. The change of the type of the light source has a significant impact on all analyzed features.
Luffing Boom Cranes are type of cranes used for load carrying in building sites. They have complex structure with big dimensions and mechanisms. Their working usage is high. Main cycles of the work of Luffing Boom cranes are: lifting and lowering the working load, Boom luffing – upwards and downwards, rotation around vertical axes, and (if mobile type) translational movement forward and backwards. In this work, we are going to study the work of this crane while rotating with full loading. Study will be done using simulations with computer applications. The aim is to see the effects of dynamic forces and moments in the crane’s main parts – metal construction, cables, and constraints during rotational work cycle, particularly at the start and end of the rotation. Also interest is to study the effects of load swinging in crane’s stability. For this purpose, we modeled with software entire luffing boom crane. Crane is modeled from standard manufacturer, as a common model of luffing boom Crane.
Submerged arc welding is one of the most extensively used process for production of spiral welded steel pipes. Production process includes pipe forming by cold plastic deformation of hot rolled strips and double-sided submerged arc welding of the strip edges.
The double-sided welded seam as an integral part of the final steel pipes must be carefully controlled because plays principal role on the quality of welded steel pipes. In this respect, optical metallographic analysis of the welded joint cross section were used as efficient and effective method to control the double-sided welded seam.
The article presents a brief review of the role of optical metallographic analysis commonly used for quality evaluation of double-sided submerged arc welded steel pipes.
One of the greatest benefits when using these alternative building methods to construct affordable homes is the speed of erection.
Delivery of units will be maximized while the quality will also be improved. At the moment one of the biggest problems with the RDP houses is the speed of delivery which causes the housing backlog in South Africa. This system has developed into a construction technology that addresses eight key challenges embodied in the low cost and affordable housing shortages facing developing and design tables to aid rapid selection of light steel sections, depending on the span, the loading and the steel grade used.
To the modern machines, especially those for the workflow automating, have been made more greater demands regarding the accuracy of their work under different conditions. In relation to this, in most constructions have been used linear bearings, which are especially suitable because of a number of their advantages.
The present article aims to show the dimensioning of a linear roller bearing of specifically selected series, depending on the speed and acceleration at work, as forces and friction coefficients in different parts of the bearing have been previously specified and taken into account in the calculation.
As a result of the dimensioning it becomes possible to determine the duration of operation of the linear roller bearing of the so-set conditions, and the deformations in the various parts under load.
The energy input in fluidized beds is usually performed by convection. In this case, the fluid stream is heated through a heater before entering the fluidized bed chamber. This method has long heating and cooling time. Therefore the purpose of this work is to find out other energy input options in fluidized beds. Such as, the induction heating is suggested. In this case, the fluidizing gas is not the source of energy, but the electrically conductive inert particles (like iron hollow spheres) into the fluidized bed, in which an induction electromagnetic field is transferred. On the surface of these particles, the heat is released directly into the fluidized bed. Here, since the heat is emitted via a large overall surface of the bed material, a very high energy density and, finally, highly efficient heat transfer can be achieved. In this way, the energy efficiency of fluidized bed processes can be significantly increased.
Mixtures of 10, 20 and 30 wt. % of tungsten carbide powder and aluminum powder were ball milled for 2, 4 and 8 hrs to investigate the effect of percentages of the reinforcement and mechanical alloying time on microstructural properties of the produced composite powders. Finer particles were tried to obtain in ductile matrix. The milled powders were analyzed using X-ray diffraction (XRD).
Nano/micro particle size and distribution (PSD) technique was used to measure particle size and distribution. Scanning electron microscopy (SEM) was also performed to observe particle morphology.
By recycling old products mainly the elements, which are contained in large amounts in the product, are regained. Taking metal coated Waste Electrical and Electronic Equipment (WEEE) as an example, this is the plate of the component cover, which is made of steel or aluminum, the included plastic, the printed circuit board’s material and copper. Those materials, which are contained on the printed circuit board belonging to the area of specialty metals such as tantalum, indium, palladium etc., cannot economically be extracted from a shredder plant’s output mass flow. To solve this problem, a new approach for an automatic decomposition of metal coated components is introduced based on the process principle of the roll crusher. For finding a solution the systematic design approach and a first pilot plant’s results are presented. Based on these results, conclusions for future developments are derived.
The widely used metal rolling bearings are only suitable for use in a process fluid by solving serious difficulties in sealing.
Process fluids (water, alkali or acid fluids, apple juice, wine or perhaps milk…) have an adverse effect on the operation of bearings. In these cases, on the one hand the occurring corrosive effects must be expected as well as the inadequate lubrication of bearings. By now, due to the large development of materials science and manufacturing processes bearings with plastic outer and inner race and some kind of aseptic rolling element (e.g. glass, acid-resistant steel or ceramic) have appeared in the areas of rolling bearings. In the Institute of Mechanics and Machinery of Gödöllő Szent István University there are studies conducted as to how these bearings made of non-standard materials behave in different process fluids.
Modern machines allow to position cutting tools relative to the workpiece with an accuracy of 1 micron, but increasing of producing detail accuracy can be achieved only by an increase of sharpness of the cutting tool, which will guarantee allow to cut required metal pads of the size of 2 … 5 microns, and will reduce the time spent on finishing operations. Existing manufacturing techniques and sharpening of cutting tools let to receive the sharpness of the blade up to 10 microns. A further increase of sharpness is only possible with the use of high-speed sharpening.
FUNDAMENTAL TRAINING IN COMPUTER AIDED DESIGNING FOR PROFESSIONAL QUALIFICATION WITHIN THE FIELD OF GENERAL ENGINEERINGpg(s) 49-51
The present article offers an approach for more effective fundamental preparation for the work with CAD systems within the technical field of Basics in Construction. The approach is based on developed, and justified versions for practical application of fundamental computer aided designing of hydro mechanical elements and mechanical drives that are used throughout the training of students. Their 3D geometrical models present options for computer aided simulation, size analysis during designing of assembled units as well as options for training of master degree students in an optional field of Expert Systems. The obtained results are also useful for the purpose of better connections between general technical subjects and profiling subjects.
STRUCTURE AND PROPERTIES OF SURFACE LAYERS METALS ON THE BASIS OF HIGH SOLID BORIDE OBTAINED IN CONDITIONS OF AN EXTERNAL MAGNETIC FIELDpg(s) 52-55
In this paper we study the structure, phase composition, microhardness, crack resistance, wear resistance boride coatings obtained at complex saturation with boron and copper in the application of an external magnetic field (EMF). Investigations have shown that this method allows the application of boride coatings in 1.5 – 2 times decrease the duration saturation detail, and receive coating with high hardness, wear resistance, crack resistance.
It is established that the application EMF formed a continuous, homogeneous boride layer with thickness coatings in 2 times higher than boride coatings without EMF for the equal duration of the process. When imposing EMF in boride layers observed the redistribution quantitative relation boride phases, namely: decrease of volume phase FeB, and on diffractograms surface layers boride coatings obtained after boriding fixed presence phases FeB and Fe2B. After complex saturation boron and copper in the application of external magnetic fields fixed phases FeB and Cu.
The researches have shown that the highest spalling stress value is reached in boride phases, obtained in powder environments with copper powder at the application of EMF, and respectively is 420 compared with 225 MPa for coating obtained without EMF. Increased shear stress values in complex layers obtained after saturation with boron and copper caused by the formation of phases more viscosity, for which crack K1c in 1.4 – 2.0 times higher than the initial boride phases FeB and Fe2B.
Application of EMF at boriding improves tribological characteristics of coatings: decreases coefficient of friction and increase in 1.5 – 2.5 times wear resistance.
The efficiency of V-belt drives is determined by several factors collectively: the slip occurring during drive transmission, the external friction occurring when the belt enters and exits the pulley as well as the hysteresis loss resulting from inner friction. Main objective of this paper is analyzing the temperature conditions of V-belt by infrared thermal camera depending on various belt pulley parallel and angle misalignment. A certain V-belt cross section was analyzed on a self developed test equipment in various belt pulley parallel and angle misalignment. It was stated that the temperature increase of V-belt is influenced by the geometrical misalignment. In this study an experimental method was developed to define the V-belt temperature increase in function of belt pulley parallel and angle misalignment. On the bases of the test results optimal parameters can be calculated that serve as beneficial references for designing and tuning V-belt drives.
PHP is one of the most popular programming languages for web applications backend development. In order to quickly develop an application, many companies have created their own frameworks. Today, there are hundreds of frameworks in PHP, but all are not equally popular. Only a few of them stand on top of the most popular frameworks (Zend, Codeigniter, Yii, CakePHP, Symfony, Laravel). Each of these frameworks has its own advantage over others, some are faster in database operations, other are better in security, or allow rapid application development. The choice of which framework will be used for development depends from application needs. One of the most important aspects when we are choosing framework is speed, no one wants to wait long for loading some web page. Even Google have clearly stated that all those sites which needs more than 2 seconds to load will be rated negative. In this article we elaborated three of the most used PHP frameworks (Yii, Zend and Codeigniter) and we test them how quickly will retrieve data from database.
The scientific paper deals with the theoretical investigations of turning clamping chucks adaptive clamping elements made by intentional imposition of deformation zones in their design. The estimation of clamping conditions in the contact zone between adaptive clamping elements and clamping surface was carried out with a help of CAD/CAE systems. The stress state of the given clamping jaw adaptive zone was analyzed.
ON THE ISSUE OF REGIONALIZATION OF ENGINEERING AND TECHNICAL EDUCATION (FOR EXAMPLE, THE URAL REGION)pg(s) 68-70
This article discusses some of the issues of regionalization of engineering education in the Urals. An urgent task is to prepare the technical colleges of engineers, competitive on regional labor markets. The article describes the two major manifestations of the regionalization of the Urals: a) the process of distribution of graduates after graduation; b) the process of obtaining a degree in a technical college. Conclusions and suggestions are based on the author’s survey conducted in 2014 using a content analysis of autobiographical information.
The goal of this paper is to propose a new ankle rehabilitation platform, which can realize a large range of ankle related foot movements. In designing the rehabilitation system, we assume that the device must provide dorsiflexion/plantar flexion and inversion/eversion movements, necessary for complete recovery of the ankle joint. Therefore the system must be spatial oriented (rotations around two perpendicular axes, hence two degrees of freedom). The device should aim to achieve low cost, low weight and ease of practical realization of the device. We present structural and kinematic aspects of the proposed device for ankle rehabilitation.
The paper presents concepts related to analysis of mechanical vibrations of a squirrel-cage induction motor. It describes an experimental approach using piezoelectric accelerometer and analog/digital data acquisition tools. The influence of powering the motor with an inverter on vibration harmonic content is presented and different PWM switching frequencies are compared to regular line supply.
Direct Metal Laser Sintering (DMLS) is a revolutionary technology that allows a production of fully functional metal parts directly from a 3D CAD data, eliminating the investment to production tools and technologies which brings considerable cost and time savings. Metal parts made by DMLS technology are fully comparable with casted or machined parts. A range of application of DMLS technologies is very wide – from prototypes, through short-run production to final products. Advantages of DMLS technology are arising along with complexity of parts – more complex geometry of parts (in terms of shape and occurrence of the detail) make DMLS technology even more economically effective.
Performance of work operations by a motor-grader is accompanied by action of asymmetrically applied external loading. As dissipative forces act between the wheels and the support surface, this force action leads to the grader deviation from the set trajectory of movement. The experimentally developed model of the vehicle behavior at performing work operations allows estimating indexes of road- holding ability depending on soil characteristics, geometric and kinematic parameters of the machine.
The paper describes the process of determining the blast load on structures and provides a numerical example of a fictive structure exposed to this load. The aim was to become familiar with the issue of blast load because of ever growing terrorist threat and the lack of guidelines from national and European regulations on the verification of structures exposed to explosions. The blast load was analytically determined as a pressure-time history.