scholarly journals Method for calculating the «mamsar+a» coupling with rope-core elements

2021 ◽  
pp. 96-103
Author(s):  
М.А. Минасян ◽  
Ц. Цзэн ◽  
А.М. Минасян
Keyword(s):  
Twist Angle ◽  
Experimental Studies ◽  
Original Method ◽  
The Finite Element Method ◽  
Diesel Generator ◽  
Working Length ◽  
Core Elements ◽  
Calculation Results ◽  
Twisting Angle ◽  
Exact Dependence

Цель представленной статьи – ознакомление читателей с оригинальной методикой расчета канатностержневой муфты «MAMSAR+A». Методика расчета канатностержневой муфты рассматривается применительно к экспериментальному дизель-генераторному агрегату мощностью 9,56 кВт при частоте вращения 1500 мин-1с дизелем 2Ч8,5/11 и генератором «КГ-5,6». Расчетная рабочая длина канатных стержней 90 мм, диаметр каната 12 мм с шестью одинаковыми прядями. Максимальный угол закручивания канатностержневой муфты принят 30°. Задача состоит в выводе уточненной зависимости угла закручивания от величины крутящего момента на основе теоретических и экспериментальных исследований для определения количества канатных стержней при заданных значениях диаметра и длины канатного стержня. Оригинальность методики заключается: 1. Учитывая, что канатностержневая муфта «MAMSAR+A» содержит несколько канатных стержней, каждый из которых состоит из шести прядей, то зависимость угла закручивания от величины крутящего момента изначально рассчитывается для одной пряди. 2. Зависимость угла закручивания от величины крутящего момента пряди получена по известной формуле для цилиндрического торсиона и методом конечных элементов. Далее путем умножения результатов расчета на число прядей получены значения для одного центрального и трех канатных стержней. Оси последних расположены по диаметру окружности равномерно под углом 120°. 3. Зависимость угла закручивания от величины крутящего момента одного центрального и трех канатных стержней получена также экспериментально с использованием специально разработанных авторами устройств. 4. На основе теоретических и экспериментальных исследований получены поправочные коэффициенты, обеспечивающие возможность получения точной зависимости угла закручивания канатного стержня от величины крутящего момента, а из нее уже необходимое их количество для всей муфты. Данная методика применима также для расчета канатных муфт в том числе и для других диаметров каната. The purpose of this article is to familiarize readers with the original method of calculating the rope-rod coupling «MAMSAR+A». The method of calculating the rope-rod coupling is considered in relation to an experimental diesel generator unit with a power of 9.56 kW at a rotation speed of 1500 min-1 with a diesel 2H8,5/11 and a generator "KG-5.6". The estimated working length of the rope rods is 90 mm, the diameter of the rope is 12 mm with six identical strands. The maximum twisting angle of the rope-rod coupling is 30°. The task is to derive a refined dependence of the twisting angle on the torque value based on theoretical and experimental studies to determine the number of rope rods at specified values of the diameter and length of the rope rod. The originality of the method: 1. Considering that the «MAMSAR+A» rope-rod coupling contains several rope rods, each of which consists of six strands, the dependence of the twisting angle on the torque value is initially calculated for one strand. 2. The Dependence of the twist angle on the value of the torque of the strand is obtained by the well-known formula for the cylindrical torsion and the finite element method. Further, by multiplying the calculation results by the number of strands, the values for one Central and three rope rods are obtained. The axes of the latter are evenly spaced along the circumference of the circle at an angle of 120°. 3. The Dependence of the twisting angle on the torque value of one Central and three rope rods was also obtained experimentally using devices specially developed by the authors. 4. Based on theoretical and experimental studies, correction coefficients have been obtained that make it possible to obtain an exact dependence of the twisting angle of the rope rod on the torque value, and from it the necessary number of them for the entire coupling. This method is also applicable for calculating rope couplings, including for other rope diameters.

scholarly journals Method for calculating the «mamsar+a» coupling with rope-core elements

2020 ◽  
Author(s):  
М.А. Минасян ◽  
Ц. Цзэн ◽  
А.М. Минасян
Keyword(s):  
Twist Angle ◽  
Experimental Studies ◽  
Original Method ◽  
The Finite Element Method ◽  
Diesel Generator ◽  
Working Length ◽  
Core Elements ◽  
Calculation Results ◽  
Twisting Angle ◽  
Exact Dependence

Цель представленной статьи – ознакомление читателей с оригинальной методикой расчета канатностержневой муфты «MAMSAR+A». Методика расчета канатностержневой муфты рассматривается применительно к экспериментальному дизель-генераторному агрегату мощностью 9,56 кВт при частоте вращения 1500 мин-1с дизелем 2Ч8,5/11 и генератором «КГ-5,6». Расчетная рабочая длина канатных стержней 90 мм, диаметр каната 12 мм с шестью одинаковыми прядями. Максимальный угол закручивания канатностержневой муфты принят 30°. Задача состоит в выводе уточненной зависимости угла закручивания от величины крутящего момента на основе теоретических и экспериментальных исследований для определения количества канатных стержней при заданных значениях диаметра и длины канатного стержня. Оригинальность методики заключается: 1. Учитывая, что канатностержневая муфта «MAMSAR+A» содержит несколько канатных стержней, каждый из которых состоит из шести прядей, то зависимость угла закручивания от величины крутящего момента изначально рассчитывается для одной пряди. 2. Зависимость угла закручивания от величины крутящего момента пряди получена по известной формуле для цилиндрического торсиона и методом конечных элементов. Далее путем умножения результатов расчета на число прядей получены значения для одного центрального и трех канатных стержней. Оси последних расположены по диаметру окружности равномерно под углом 120°. 3. Зависимость угла закручивания от величины крутящего момента одного центрального и трех канатных стержней получена также экспериментально с использованием специально разработанных авторами устройств. 4. На основе теоретических и экспериментальных исследований получены поправочные коэффициенты, обеспечивающие возможность получения точной зависимости угла закручивания канатного стержня от величины крутящего момента, а из нее уже необходимое их количество для всей муфты. Данная методика применима также для расчета канатных муфт в том числе и для других диаметров каната. The purpose of this article is to familiarize readers with the original method of calculating the rope-rod coupling «MAMSAR+A». The method of calculating the rope-rod coupling is considered in relation to an experimental diesel generator unit with a power of 9.56 kW at a rotation speed of 1500 min-1 with a diesel 2H8,5/11 and a generator "KG-5.6". The estimated working length of the rope rods is 90 mm, the diameter of the rope is 12 mm with six identical strands. The maximum twisting angle of the rope-rod coupling is 30°. The task is to derive a refined dependence of the twisting angle on the torque value based on theoretical and experimental studies to determine the number of rope rods at specified values of the diameter and length of the rope rod. The originality of the method: 1. Considering that the «MAMSAR+A» rope-rod coupling contains several rope rods, each of which consists of six strands, the dependence of the twisting angle on the torque value is initially calculated for one strand. 2. The Dependence of the twist angle on the value of the torque of the strand is obtained by the well-known formula for the cylindrical torsion and the finite element method. Further, by multiplying the calculation results by the number of strands, the values for one Central and three rope rods are obtained. The axes of the latter are evenly spaced along the circumference of the circle at an angle of 120°. 3. The Dependence of the twisting angle on the torque value of one Central and three rope rods was also obtained experimentally using devices specially developed by the authors. 4. Based on theoretical and experimental studies, correction coefficients have been obtained that make it possible to obtain an exact dependence of the twisting angle of the rope rod on the torque value, and from it the necessary number of them for the entire coupling. This method is also applicable for calculating rope couplings, including for other rope diameters.

Method of experimental evaluation of the efficiency coefficient of vibration protection of the rope-rod coupling "MAMSAR+A" of the diesel generator set DGA-8.83

2021 ◽  
pp. 88-95
Author(s):  
М.А. Минасян ◽  
А.М. Минасян ◽  
Ц. Цзэн
Keyword(s):  
Experimental Evaluation ◽  
Vibration Isolation ◽  
Experimental Studies ◽  
Original Method ◽  
Efficiency Coefficient ◽  
Diesel Generator ◽  
Vibration Protection ◽  
Rigid Connection ◽  
Two Stages

Объектом исследования является опытный образец запатентованной канатностержневой муфты (КСМ) «MAMSAR+А» в качестве привода дизель-генераторного агрегата ДГА-8,83 мощностью 9,56 кВт при частоте вращения 1500 мин-1 с дизелем 2Ч 8,5/11 и генератором «ГК-5,6». Целью исследования является экспериментальная оценка коэффициента эффективности вибрационной защиты КСМ. Поставленная цель достигается разработкой и реализацией оригинальной методики экспериментальной оценки коэффициента эффективности КСМ с анализом и выводами результатов экспериментальных исследований. Экспериментальные исследования проводятся в два этапа. Первый этап – с упругим соединением КСМ, второй этап – с жестким соединением. Оригинальность методики экспериментальной оценки коэффициента эффективности вибрационной защиты КСМ главным образом заключается в том, что между двумя этапами экспериментальных исследований КСМ не демонтируется. Следовательно, качество центровки не нарушается. Усредненный коэффициент эффективности виброизоляции КСМ составляет от 3 до 8 дБ. The object of this research is a prototype of the patented wire rope coupling (KSM) "MAMSAR+A" as a drive for a diesel-generator unit DGA-8.83 with a power of 9.56 kW at a speed of 1500 min-1 with a 2CH 8.5/11 diesel engine and a generator "KG-5.6". The aim of the research is to experimentally evaluate the efficiency coefficient of vibration protection of the KSM. This goal is achieved by developing and implementing an original method for experimental evaluation the efficiency coefficient of the KSM with analysis and conclusions of the results of experimental studies. Experimental studies are conducted in two stages. The first stage - with an elastic connection of the coupling, the second stage - with a rigid connection. The originality of the method of experimental evaluation of the efficiency coefficient of vibration protection of the KSM mainly lies in the fact that the KSM is not dismantled between the two stages of experimental research. Therefore, the quality of alignment is not violated. The average coefficient of vibration isolation efficiency of the KSM is from 3 to 8 dB.

scholarly journals Preparation of reasonable initial data for analytical and experimental studies of torsional vibrations of the universal diesel generator set DG-8.83

2020 ◽  
Author(s):  
М.А. Минасян ◽  
Ц. Цзэн ◽  
А.М. Минасян
Keyword(s):  
Initial Data ◽  
Power Plants ◽  
Experimental Studies ◽  
Torsional Vibrations ◽  
The Finite Element Method ◽  
Diesel Generator ◽  
Empirical Formulas ◽  
Moments Of Inertia ◽  
Reasonable Choice ◽  
Elastic Couplings

Крутильные колебания упруго-массовых систем относятся к тем опасным динамическим нагрузкам, которые могут приводить к аварийным повреждениям валов, упругих муфт и других элементов энергетических установок с дизельным приводом. Указанные особенности побудили авторов на первом этапе аналитических и экспериментальных исследований крутильных колебаний универсальной дизель – генераторной установки ДГ-8,83 подготовить обоснованные исходные данные. Для этой цели определены моменты инерции и податливости элементов крутильной системы по известным эмпирическим формулам, по методу конечных элементов и частично экспериментально. Затем на основе анализа и обобщения полученных результатов проведен обоснованный выбор моментов инерции и податливостей в качестве уточненных исходных данных. На базе выбранных исходных данных авторы намерены приступить к расчету крутильных колебаний с жестким и упругим соединением дизеля с генератором. Для обеспечения точности аналитических и экспериментальных исследований крутильных колебаний других дизельных установок авторы рекомендуют, прежде всего, подготовки обоснованных исходных данных. orsional vibrations of elastic-mass systems belong to those dangerous dynamic loads that can lead to emergency damage to shafts, elastic couplings and other elements of power plants with a diesel drive. These features prompted the authors to prepare reasonable initial data at the first stage of analytical and experimental studies of torsional vibrations of the universal diesel generator set DG-8.83. For this purpose, the moments of inertia and pliability of the elements of the torsion system are determined using known empirical formulas, the finite element method, and partially experimentally. Then, based on the analysis and generalization of the results obtained, a reasonable choice of moments of inertia and pliability was made as updated initial data. Based on the selected initial data, the authors intend to start calculating torsional vibrations with a rigid and elastic connection of a diesel engine with a generator. To ensure the accuracy of analytical and experimental studies of torsional vibrations of other diesel installations, the authors recommend, first, the preparation of reasonable initial data.

scholarly journals Influence of Coronal Preflaring on the Accuracy of Electronic Working Length Determination: Systematic Review and Meta-Analysis

2021 ◽  
Vol 10 (13) ◽  
pp. 2760
Author(s):  
María León-López ◽  
Daniel Cabanillas-Balsera ◽  
Victoria Areal-Quecuty ◽  
Jenifer Martín-González ◽  
María C. Jiménez-Sánchez ◽  
...  
Keyword(s):  
Systematic Review ◽  
Science Studies ◽  
Meta Analysis ◽  
Experimental Studies ◽  
Risk Of Bias ◽  
Permanent Teeth ◽  
Total Risk ◽  
Human Teeth ◽  
Working Length ◽  
Meta Analyses

Aim. To conduct a systematic review and meta-analysis according to the following PICO question: in extracted human permanent teeth, does preflaring, compared with unflared canals, influence the accuracy of WL determination with EAL? Material and Methods. A systematic review was conducted according to the PRISMA checklist, using the following databases: PubMed, Science Direct, Scopus, and Web of Science. Studies related to WL determination using EAL both in preflared and unflared root canals of extracted human teeth were included. The outcome of interest was the accuracy of the electronic WL determination. A quality assessment of the included studies was performed, determining the risk of bias. The meta-analyses were calculated with the 5.4 RevMan software using the inverse variance method with random effects. PROSPERO registration: CRD42021243412. Results. Ten experimental studies fulfilled the inclusion criteria, and most of them found that preflaring increases the accuracy of the EALs in WL determination. The calculated OR was 1.98 (95% CI = 1.65–2.37; p < 0.00001; I2 = 10%), indicating that the determination of WL by EALs is almost twice as accurate in preflared canals. The accuracy of Root ZX in WL determination increases more than three times (OR = 3.25; p < 0.00001). Preflaring with Protaper files significantly increases the accuracy of EALs (OR = 1.76; p < 0.00001). The total risk of bias of the included studies was low. No obvious publication bias was observed. Conclusions. The results indicate a significant increase in the accuracy of WL determination with EAL after preflaring, doubling the percentage of exact measurements. Preflaring should be recommended as an important step during mechanical enlargement of the root canal, not only because it improves the access of the files to the canal, but also because it allows one to obtain more accurate electronic determinations of WL.

scholarly journals Investigations on Torsion of the Two-Chords Single Laced Members

2017 ◽  
Vol 25 (2) ◽  
pp. 147-160
Author(s):  
Paweł Lorkowski ◽  
Bronisław Gosowski
Keyword(s):  
Cross Sections ◽  
Experimental Studies ◽  
The Finite Element Method ◽  
Second Moment ◽  
Steel Columns ◽  
Numerical Studies ◽  
Traction Network ◽  
Railway Traction ◽  
Parametric Analyses ◽  
The Relationship

Abstract The paper presents experimental and numerical studies to determine the equivalent second moment of area of the uniform torsion of the two-chord steel single laced members. The members are used as poles of railway traction network gates, and steel columns of framed buildings as well. The stiffness of uniform torsion of this kind of columns allows to the determine the critical loads of the spatial stability. The experimental studies have been realized on a single - span members with rotation arrested at their ends, loaded by a torque applied at the mid-span. The relationship between angle of rotation of the considered cross-section and the torque has been determined. Appropriate numerical model was created in the ABAQUS program, based on the finite element method. A very good compatibility has been observed between experimental and numerical studies. The equivalent second moment of area of the uniform torsion for analysed members has been determined by comparing the experimental and analytical results to those obtained from differential equation of non-uniform torsion, based on Vlasov’s theory. Additionally, the parametric analyses of similar members subjected to the uniform torsion, for the richer range of cross-sections have been carried out by the means of SOFiSTiK program. The purpose of the latter was determining parametrical formulas for calculation of the second moment of area of uniform torsion.

scholarly journals NUMERICAL ANALYSIS OF CORRUGATED STEEL PLATE BRIDGE WITH REINFORCED CONCRETE RELIEVING SLAB

2015 ◽  
Vol 22 (5) ◽  
pp. 585-596 ◽  
Author(s):  
Damian BEBEN ◽  
Adam STRYCZEK
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Steel Plate ◽  
Numerical Models ◽  
Experimental Tests ◽  
Bridge Engineering ◽  
Steel Plates ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Rc Slab

The paper presents a numerical analysis of corrugated steel plate (CSP) bridge with reinforced concrete (RC) relieving slab under static loads. Calculations were made based on the finite element method using Abaqus software. Two computation models were used; in the first one, RC slab was used, and the other was without it. The effect of RC slab to deformations of CSP shell was determined. Comparing the computational results from two numerical models, it can be concluded that when the relieving slab is applied, substantial reductions in displacements, stresses, bending mo­ments and axial thrusts are achieved. Relative reductions of displacements were in the range of 53–66%, and stresses of 73–82%. Maximum displacements and bending moments were obtained at the shell crown, and maximum stresses and axial thrusts at the quarter points. The calculation results were also compared to the values from experimental tests. The course of computed displacements and stresses is similar to those obtained from experimental tests, although the absolute values were generally higher than the measured ones. Results of numerical analyses can be useful for bridge engineering, with particular regard to bridges and culverts made from corrugated steel plates for the range of necessity of using additional relieving elements.

scholarly journals Cause Analysis and Countermeasures of a Breakdown Failure of Flexible 110 kV Cable Terminal

2018 ◽  
Vol 38 ◽  
pp. 04004
Author(s):  
Feng Huang
Keyword(s):  
Electric Field ◽  
Electric Field Intensity ◽  
Field Model ◽  
Semiconductor Layer ◽  
Mechanism Analysis ◽  
The Finite Element Method ◽  
Cable Insulation ◽  
Cause Analysis ◽  
Breakdown Mechanism ◽  
Calculation Results

disintegration examination and analysis are employed in flexible terminal breakdown of 110 kV XLPE insulated cables. It is considered that the main reason of breakdown is the separation of the stress cone of the terminal and the fracture of the semi- conductive layer of the cable insulation. Therefore, the finite element method is used to electric field model and simulate the dislocation fault of internal stress cone and outer semiconductor layer of cable insulation. The distribution of the electric field intensity is calculated and compared. The simulation and calculation results verify the validity of the breakdown mechanism analysis, and put forward some practical suggestions.

scholarly journals Research of transient processes in case of single-phase insulation faults in low-voltage ship power grids, taking into account the resistance at the fault point

2020 ◽  
pp. 49-54
Author(s):  
И.Е. Кажекин
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Experimental Studies ◽  
Power Grids ◽  
Transient Processes ◽  
Safety Issues ◽  
Physical Experiments ◽  
Marine Industry ◽  
Calculation Results ◽  
Constant Potential

В работе рассмотрены вопросы безопасности бортовых электросетей объектов морской индустрии, показано влияние перенапряжений на их основные показатели, которыми определяются опасности смертельных электротравм, опасности возникновения пожаров и взрывов. Представлены результаты математического моделирования электрического разряда по уравнению Майра с учетом особенностей переходного процесса при однофазных замыканиях на корпус. Показана роль напряжения смещения нейтрали по постоянному потенциалу, наибольшие значения которого формируются при неустойчивом контакте фазы с корпусом судна. Описаны результаты экспериментальных исследований переходных процессов, сопровождающихся возникновением неустойчивыми искровыми разрядами. Сравнение результатов расчета по предложенной методике с результатами физических экспериментов показало весьма удовлетворительную сходимость. Предложенная модель может быть использована для уточнения показателей, характеризующих безопасность судовых электросетей. The paper deals with the safety issues of on-board power grids of the marine industry facilities, shows the influence of overvoltages on their main indicators, which determine the dangers of fatal electrical injuries, the risk of fires and explosions. The results of mathematical modeling of an electric discharge according to the Mayr equation, taking into account the features of the transient process in single-phase short circuits to the case, are presented. The role of the bias voltage of the neutral at a constant potential is shown, the highest values ​​of which are formed during unstable contact of the phase with the ship's hull. The results of experimental studies of transient processes accompanied by the appearance of unstable spark discharges are described. Comparison of the calculation results by the proposed method with the results of physical experiments showed a very satisfactory convergence. The proposed model can be used to refine the indicators characterizing the safety of ship power grids.

scholarly journals ANÁLISE NUMÉRICA DE PERFIS DE AÇO FORMADOS A FRIO EM SEÇÃO “I” CONSTITUÍDA POR DUPLO “U” SUBMETIDOS À COMPRESSÃO

2020 ◽  
Vol 12 (1) ◽  
pp. 95-110
Author(s):  
Gabriel Cintra Macedo ◽  
Wanderson Fernando Maia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Plate Thickness ◽  
Experimental Studies ◽  
Structural Behavior ◽  
The Finite Element Method ◽  
Geometric Imperfections ◽  
Initial Geometric Imperfections ◽  
Normal Strength ◽  
Double Channel

Although the section “I”, in double channel, is widely used, there are few studies on its behavior. Therefore, this work aims to contribute to a greater mastery over the structural behavior of this built-up sections. A nonlinear numerical analysis was performed using the Finite Element Method in the Ansys program, using existing experimental studies as a comparative database. The effect of length, number of connections, plate thickness and the presence of geometric and material imperfections on the normal strength of the columns. For this analysis, it was essential to consider the initial geometric imperfections, because there was a considerable reduction in the normal strength of the columns, thus getting closer to the values obtained experimentally. With regard to normative procedures, values against security were found in most cases, showing the need to conduct further studies in the area for the development of more appropriate formulations.

scholarly journals STUDY OF THE EFFECTIVENESS OF VIBRATION ISOLATION OF UNCONVENTIONAL TOROIDAL ROPE VIBRATION ISOLATORS IN DIESEL UNITS VIBRATION ISOLATION SYSTEM

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 110-114
Author(s):  
Minas Minasyan ◽  
Armen Minasyan ◽  
Aung Thant
Keyword(s):  
Power Plants ◽  
Vibration Isolation ◽  
Steel Wire ◽  
Experimental Studies ◽  
Wire Rope ◽  
Diesel Generator ◽  
Isolation System ◽  
Vibration Isolators ◽  
Before And After ◽  
Materials Used

The paper notes that the structure of the wire rope is one of the most suitable materials used as a fire-resistant elastic element of vibration-insulating structures and fasteners (vibration isolators). To solve the problems of vibration isolation of marine diesel power plants in the framework of development and improvement of the shock absorption system, the original patented elastic supports with elastic elements made of steel wire rope in the form of a torus are presented. When commercially available vibration isolators do not meet the relevant requirements of vibration protection of a particular object, the solution to the existing problem can be achieved by using the proposed wire rope vibration isolators. The technical results of the original patented inventions are: - equal stiffness in the horizontal plane - ensuring the reliability and high vibration efficiency of protection against impacts and shocks. The proposed designs of vibration isolators are easy (technological in manufacturing) to manufacture and assemble, reliable and durable - the service life is 10 years or more. Vibration efficiency is confirmed by the vibration acceleration spectra before and after the vibration isolator of the damping system of the ship diesel-generator DGA-500 and the diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame. The three-year trial life of the DGA-500 and experimental studies on a diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame confirms their efficiency and effectiveness.

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