Papers by Keyword: Breakage

Abstract: The purpose of research is to justify a calculation method for a stay rope of composite fiber structure with a breakage in fiber continuity. Research methodology is in constructing and solving a deformation model of a composite fiber stay rope with continuity breakage of one of its fibers. The calculation method of a stress-strain state of a stay rope of composite fiber structure considering the breakage of one of its fibers is established. The scientific novelty of research is in determining that the length of manifestation of a local disturbance of a stress-strain state of composite stay rope is proportional to a square root of a ratio of tensile modulus of a reinforcing element material and shear modulus of an elastic material that connects them. The practical value of the research is in that the calculation method allows reasonable prediction of a tractive capacity loss of a stay rope as a result of breakage of any of its reinforcing elements. The known value of residual tractive capacity allows reasonable selection of a safety margin for a stay rope, which ensures a sufficient level of reliability of a cable-stayed bridge.

Abstract: Improving the production efficiency is the task with the increasing difficulty. Therefore, it is important to constantly expand the set of tools and perfect the methodology for improving the processes. Some of the losses associated with the negative technological events (breaks, drifting, etc.) are difficult to eliminate completely due to the complexity of making changes to the basic technology. But if you know in advance that the event will occur, you can significantly reduce the probability and consequences, thereby significantly improve the efficiency of the production process. Therefore, it is important to develop and introduce the applied approaches to forecasting the negative technological events in the production processes. This paper presents the method of the forecast-event statistical analysis of the cause-and-effect relationships. The technique was tested on the events of strip’s breakage during rolling at the cold rolling mill 1400 and strip’s drifting in the input storage of the continuous etching unit (CEU). Based on the presented methodology, the specialized digital service was developed and introduced in the production processes of the dynamo steels shop.

Abstract: Reasons for breakage of welding rod and wire at drawing are analyzed. It is shown that the basic reason for breakage is microphysical tree-like segregation which is caused by irrational addition of boron-containing material at after-furnace treatment, low effectiveness of steel continuous casting process, unproven technology of metal electromagnetic agitation in a mold at continuous casting. Peculiarities of alloyed elements liquation, both in welding rod and wire are studied. It is shown that non-uniformity of boron, manganese and silicon distributions in the longitudinal and transversal welding rod cross sections will become the main reason for increasing wire breakage during further drawing.

Abstract: Welding is one of the joining processes and it has been widely used, especially for steel welded structure in off-shore, pipeline or ship construction. Advantages of the welding joint are inexpensive, process joining can be done quickly and can produce light structure compared to other joining processes. One of welding techniques mostly used for joining steel construction is flux cored arc welding (FCAW). The commonly problems arise in this welding technique are distortion and low resistance of crack propagation. The aim of this study is to minimize distortion and to increase fatigue crack growth resistance of weld joint.In this research, FCAW welding was conducted without preheat and the other was preheated around welding area with temperature of 200 °C. Each of temperature welding process was measured using data acquisition. After completing the welding process, a sequence of experiment was conducted including chemical compositions, distortion and fatigue test. Result of this research shows that preheat temperature of 200 °C can decrease distortion and improve fatigue performance.

Abstract: In order to find the best impact head and threshing moisture content to damage the arrangement law of maize ear,the impact test with different varieties and different moisture of the maize ear is carried out in the drop impact test bench. The experimental result shows that the breakage rate of kernel is smaller and the discrete effect of kernel is better than others in the the action of impact head when moisture content of the maize ear belongs to 14%-20% or less than 12%. The wedge impact head is the most suitable for maize kernel threshing than other impact heads.The effect of maize varieties to the breakage rate is not obvious. The research results can provide a theoretical reference for the low damage threshing method of further research.

Abstract: A new method of reliability monitoring of electrical devices based on carbon fibres is presented. Due to the thermo-mechanical stress on electronic circuits a loss of fibre network integrity can take place and potential difference may appear between the edges of broken carbon fibres. This potential difference causes an intensive field-emission from surfaces of these broken carbon fibres and an acceleration of emitted electrons. Due to the acceleration of electrons a microwave emission is generated. A CFRP was used to simulate the behaviour of a carbon based electronic device. The sequence of microwave impulses was detected in a frequency bandwidth from 8 to 12 GHz. The rise time of detected microwave impulses is about of few nanoseconds. This time is in agreement with crack formation time in carbon fibre. The correlation between the change of electrical resistance of composites and microwave impulses by fibres fracture is observed. Thus, the breakdown of current that flows through carbon fibres induces detectable microwave emission. That means that defects in electrical circuits can be wireless detected online.

Abstract: Ni/NiO/C composite nanofiber with 60 nm in diameter was prepared by electrospinning and subsequent carbonization. The composition and morphology were characterized by X-ray diffraction and scanning electron microscopy. The electrochemical properties were preliminarily evaluated. It is found that both NaOH concentration and the addition of NiCl₂ are key factors for the morphology of composite nanofibers. An electrochemical study reveals that the obtained Ni/NiO/C composite nanofiber exhibits excellent rate capability which makes it promising anode material for Li ion batteries. In addition, our simple and inexpensive stragegy can be further extended to create various functional hybrid nanomaterials.

Abstract: The population balance equation (PBE) was solved numerically by using the sectional method to investigate the effect of breakage on the agglomeration between bipolarly charged particles. Calculations showed that breakage results in the increase of small particles and the decrease of large particles bipolarly charged, compared to the case with only agglomeration effect. The breakage effects are important when simulating the agglomeration dynamics.

Abstract: The floc breakage plays an important role in the flocculation, the stable floc size or morphology distribution is the result of the equilibrium of formation and breakage. In this paper, the breakage approaches or models for different kind and size of flocs have been discussed. By introducing special breakage functions and comparing their relative values, the numbers of various flocs are verified to be still proportional to the suspension concentration compared with the situation in which the breakage is neglected. However, as illustrated in this paper, the total number of every kind of floc is still a power function of the suspension concentration for dilute suspensions where the number concentration of solid particles is linearly related to the volume concentration. This is similar to that where the breakage is disregarded, although the number for every kind of floc is inevitably changed. In addition, a potential quantitative method to analyze the relative composition of different kinds of flocs is presented by measuring the contributions of the flocs to the suspension viscosity.

Abstract: This paper presents an investigation into the roll compression induced breakage process of a coal prism within a vertical roller mill. The targeted process was characterized by strong nonlinearities arisen from large deformation, and from original continuum to final discontinuum. A numerical approach coupling the Smoothed Particle Hydrodynamics (SPH) method and the finite element method (FEM) was developed for such a type of analysis. The SPH method was used to model a coal prism and its interaction with the mill structure, while the roller and the support table in the mill were modeled with the FEM. This computational model makes it possible to predict the deformation and progressive disintegration process in the coal prism, as well as the reaction force mobilized along the specimen-roller interface. Using a cubic coal specimen as an instance, the paper presents a preliminary numerical study under prescribed geometry and working conditions of a mill machine. Typical results of the breakage process as well as the development of contact force were provided and discussed.