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  • Experimental investigation on the quality of holes in the multi-layered GFRP-titanium obtained in drilling operations

    The purpose of this work was to study the influence of the structural and geometric parameters of the twist drill on the quality of the processed hole and productivity of machining the high strength polymeric composite material – glass fiber epoxy-based plastics that are reinforced by titanium foil. In the structure of high loaded polymeric composite parts the reinforcing layers made from the titanium foil are used. These titanium layers are placed between layers of the winding unidirectional glass fiber tape or the carbon fiber tape. In order to reach the required dimensional accuracy, the macro- and micro geometry of the hole surfaces, to eliminate the overheat, burning, and delaminations of material, need to use sharp-edged tools, which wear out quickly, and remove the drill from the workpiece at frequent intervals to clean the chips from the flutes of the drill and the hole being drilled. We studied the drilling of glass fiber reinforced laminates at the different schemes of sharpening the drills made from the high-speed steel. We present some experimental results of the optimal feed and speed for the studied twist drills, the dependencies of the highness parameters of roughness, and also characters and degree of delamination at starting and finishing hole for the different tools, feed and cutting speed.

    Keywords: GFRP, drilling GFRP, delaminations, double-angle sharpening

  • Joint-stock insurance business on the Don in the second half of XIX - early XX centuries

    History share of insurance business in the Province of the Don, the characteristic four stages of development process, the analysis in general and the specific activity of sixteen joint campaigns, including foreign, on the Don in the late XIX - early XX centuries. ("New York", "Urbain", "Ekvitebl"). The social composition of the policyholders, insurance forms discounts logic of competition  

    Keywords: insurance organization of insurance business corporate insurance insured event insurance discount insurance premium insurance rates insurance capital

  • Оптимизация режима формования полимерных композитных конструкций на основе метода Парето

    Одним из важнейших факторов, исключающих возникновение дефектов типа пор, расслоений, участков с неполной полимеризацией связующего в формуемой высоконагруженной полимерной композитной конструкции, является управляемость процесса во всем объеме композита. Для обеспечения однородности процесса полимеризации связующего предложен метод многокритериальной оптимизации процесса на основе математической модели, связывающей процессы распространения тепла и кинетики полимеризации. Система связанных уравнений процесса, учитывающая экзотермическое тепло, выделяемое при полимеризации термореактивного связующего, изменение теплоемкости и теплопроводности композита при фазовых переходах от жидкого к гелеобразному и, далее, к твердому состоянию, точную геометрию технологической системы, включая прессформу, а также интенсивность тепловыделения независимо управляемых нагревателей, реализована в виде конечноэлементной модели. Предложенный метод синтеза закона оптимального управления нагревателями, использующий метод множеств Парето, проиллюстрирован на примере полимеризации разностенной композитной конструкции, формуемой из стеклопластика.

    Keywords: Композиционные материалы; Процесс полимеризации; Оптимальное управление; Кинетические уравнения; Уравнения в частных производных в задачах управления и оптимизации, Конечно-элементное моделирование, Фронт Парето

  • New means for measurement of parameters of piezoelectric ceramic elements and materials

     An analysis of new methods and means for a mesurement of parameters of piezoelectric ceramic elements and materials is carried out. These methods and means are based on a digital principle of the construction of devices. An impuls with a linear frequncy modulation therein is used as an signal for exciting. Results of experimental studies on this subject are represented for discussion.     

    Keywords: piezo ceramic element, piezo, methods and means of measurement, digital signal processing

  • Diagnosis of a piezoceramic element based on the active component of conductivity

    An estimate of the frequency discretization interval was obtained in solving diagnostic problems of a piezoceramic element by means of different methods based on measuring the active component of conductivity in a number of discrete points. This allows avoiding precision loss and, at the same time, reducing the number of measurements and computational operations.

    Keywords: Piesoceramic element, Q-factor, active component of conductivity

  • Modelling of rods with defects with different types of fastening

    The task of identification of defects in rods with different variants of fastening. In the basis of lies method parameter identification based on an analysis of the frequencies and parameters of natural modes of the structure. Built model of the rod design has defects fluctuations, using finite element of the complex 

    Keywords: Defect, damage, rod, the oscillations of the cantilever rod

  • The studying of oscillations of the corpulent cantilever rod model with a defect

    Defined criteria for identification of defect parameters, on the basis of the analysis of the different modes of own fluctuations, with the use of finite element modal calculation console corpulent model of a rod with a single defect. Developed finite element model of a universal complex . Considered corpulent (3-d) model on the basis of 3D finite element Solid92. When solving the problem considered on 26 oscillation modes depending on the size of the defect and its location.

    Keywords: Damaged, defective, swing, cantilever, frequency

  • Information about authors (№4, 2013)

    Information about authors of issue №4 (2013)

    Keywords: authors

  • Information about authors (№2, 2012)

    Information about authors of issue №2 (2012)

    Keywords: authors