Experimental study of heating of a polyurethane shock absorber under cyclic loading

2020 ◽  
pp. 22-25
Author(s):  
S.N. Yakovlev
Keyword(s):  
Experimental Study ◽  
Cyclic Loading ◽  
Vibration Amplitude ◽  
Shock Absorber ◽  
Heating Temperature ◽  
Loading Frequency ◽  
Empirical Dependence ◽  
Shock Absorbers ◽  
Compression Deformation ◽  
Relative Compression

Based on the results of the experiments, an empirical dependence was obtained to determine the heating temperature of polyurethane shock absorbers of different hardness under cyclic loading, depending on the relative compression deformation, loading frequency and vibration amplitude. Keywords: polyurethane, shock absorber, heating temperature, empirical dependence. [email protected]

Calculation of the frequency of own oscillations of polyurethane shock absorbers used in shipbuilding

2020 ◽  
pp. 152-157
Author(s):  
Ю.Ф. Титова ◽  
С.Н. Яковлев
Keyword(s):  
Vibration Isolation ◽  
Shock Absorber ◽  
Free Vibrations ◽  
Empirical Dependence ◽  
Natural Vibrations ◽  
Natural Oscillations ◽  
Rubber Material ◽  
Shape Coefficient ◽  
Calculated Dependence ◽  
Shock Absorbers

В работе приведено обоснование необходимости применения амортизаторов и замены традиционного эластомерного материала резины на более совершенный материал – полиуретан. Целью работы является экспериментальное исследование деформативности полиуретанового виброизоляционного массива амортизатора и получение расчетной зависимости для определения собственной частоты колебаний системы «агрегат-амортизатор». В работе представлен подробный анализ зависимости коэффициента виброизоляции от соотношения частот вынужденных и свободных колебаний. Отмечено, что эффективность виброизоляции тем выше, чем больше это соотношение частот. Учитывая, что частота вынужденных колебаний - величина заданная, для повышения эффективности виброизоляции следует понижать частоту собственных колебаний амортизатора благодаря применению новых виброизоляционных материалов. В качестве эластомерного материала предложен полиуретан фирмы «Synair» (Великобритания) твердостью 40,45 и 50 ShA. Приведено описание нагружающего устройства для исследования деформативности виброизоляционного массива амортизатора серии КАС (корабельный амортизатор сварной). Получена эмпирическая зависимость коэффициента ужесточения в зависимости от коэффициента формы виброизоляционного массива амортизатора. Представлена эмпирическая зависимость по определению модуля упругости эластомерного материала виброизоляционного массива амортизатора в зависимости от условий контактирования на торцах и фактора формы массива. Представлена расчетная зависимость по определению частоты собственных колебаний амортизатора в зависимости от величины статической деформации. Представленная зависимость позволяет на стадии проектирования определить собственную частоту колебаний и предупредить возникновение такого опасного явления, как резонанс. The paper substantiates the need for the use of shock absorbers and the replacement of the traditional elastomeric rubber material with a more advanced material - polyurethane. The aim of the work is an experimental study of the deformability of a polyurethane vibration-isolating array of a shock absorber and obtaining a calculated dependence for determining the natural frequency of oscillations of the aggregate-shock absorber system. The paper presents a detailed analysis of the dependence of the vibration isolation coefficient on the ratio of the frequencies of forced and free vibrations. It is noted that the effectiveness of vibration isolation is higher, the greater the ratio of the frequencies of forced and natural vibrations. Taking into account the fact that the frequency of forced vibrations is a given value, to increase the efficiency of vibration isolation, it is necessary to reduce the frequency of natural vibrations of the shock absorber due to the use of new vibration insulation materials. The work describes the loading device for studying the deformability of the vibration-isolating array of the KAS series shock absorber (welded ship shock absorber). An empirical dependence of the tightening coefficient is obtained depending on the shape coefficient of the vibration-isolating array of the shock absorber. The paper presents a calculated dependence on determining the frequency of natural oscillations of the shock absorber depending on the magnitude of the static deformation.

PENGARUH SUHU PEMANASAN FORMALIN 10% TERHADAP PERKEMBANGAN TELUR Ascaris lumbricoides

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Ni Putu Aryadnyani
Keyword(s):  
Experimental Study ◽  
Environmental Factors ◽  
Ascaris Lumbricoides ◽  
Heating Temperature ◽  
Control Group ◽  
Control Group Design ◽  
Group Design ◽  
Design Result

AbstractBackground Ascaris lumbricoides eggs had very thick walls consisted of three layers, they were albuminoid layer, hyaline layer and vitelin layer. These layers were impermeable causing the Ascaris lumbricoides eggs resistant to less supportive environmental factors. Formalin 10% was a preservative that was often used to preserve faeces containing parasites such as protozoa and worm eggs. However, without heating, formalin 10% was not effective to preserve the Ascaris lumbricoides eggs because they would keep developing to become infective (containing larvae). Objective This study aims to prove whether there is an effect of adding 10% formalin which is heated at 60 C, 70 C and 80 C to the development of Ascaris lumbricoides eggs.Methods The design of this research was an experimental study with The Randomized Posttest Control Group Design. Result The Ascaris lumbricoides eggs were still growing into infective eggs in faeces although they were heated by formalin 10% at 60C, 70C and 80C. conclusion Based on the results of the study, there was no effect of heating temperature of formalin 10% on the development of Ascaris lumbricoides egg.Keywords: Formalin 10%, Ascaris lumbricoides, Heating, Soil Transmitted Helminth

Mathematical modeling of elastoplastic deformation of tubular energy-absorbing elements under static and impact loading

2020 ◽  
pp. 78-82
Author(s):  
A.Р. Evdokimov ◽  
A.N. Gromyiko ◽  
A.A. Mironov
Keyword(s):  
Mathematical Modeling ◽  
Impact Loading ◽  
Elastoplastic Deformation ◽  
Shock Absorber ◽  
Analytical Models ◽  
Dynamic Impact ◽  
Shock Absorbers ◽  
Energy Absorbing ◽  
Absorbing Elements

Analytical models of static and dynamic impact elastoplastic deformation of tubular energy-absorbing elements constituting a tubular plastic shock absorber are proposed. The developed models can be used for the calculation and design of these shock absorbers. Keywords static and dynamic elastoplastic deformation, mathematical modeling, tubular energy-absorbing element, tubular plastic shock absorber, impact loading. [email protected]

scholarly journals Factors Affecting the Dependency of Shear Strain of LRB and SHDR: Experimental Study

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 98
Author(s):  
Chao-Yong Shen ◽  
Xiang-Yun Huang ◽  
Yang-Yang Chen ◽  
Yu-Hong Ma
Keyword(s):  
Experimental Study ◽  
Low Temperature ◽  
Shear Strain ◽  
Loading Frequency ◽  
Loading Test ◽  
Characteristic Strength ◽  
Rubber Bearing ◽  
Dominant Feature ◽  
Loading Sequence ◽  
G Value

In this research we conducted a sensitivity experimental study where we explored the dependency of the shear strain on the seismic properties of bearings, namely lead rubber bearing (LRB) and super high damping rubber bearing (SHDR). The factors studied were vertical pressure, temperature, shear modulus of the inner rubber (G value), loading frequency, and loading sequence. Six specimens were adopted, i.e., three LRBs and three SHDR bearings. A series of test plans were designed. The seismic characteristics of the bearings were captured through a cyclic loading test, which included post-yield stiffness, characteristic strength, area of a single cycle of the hysteretic loop, equivalent stiffness, and equivalent damping ratio. A whole analysis of variances was then conducted. At the same time, to explore certain phenomena caused by the factors, an extended discussion was carried out. Test results showed that the temperature is the most dominant feature, whereas the G value is the least contributing factor, with the effect of the loading frequency and the loading sequence found between these two. The increment of the post-yielded stiffness for LRB from 100% to 25% is a significant reduction from a low temperature to high one. The slope of the characteristic strength versus the shear strain for LRB under high temperature is larger than the one under low temperature.

scholarly journals Study of the Mechanical Environment of Chondrocytes in Articular Cartilage Defects Repaired Area under Cyclic Compressive Loading

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Hai-Ying Liu ◽  
Hang-Tian Duan ◽  
Chun-Qiu Zhang ◽  
Wei Wang
Keyword(s):  
Articular Cartilage ◽  
Cyclic Loading ◽  
Response Curve ◽  
Fluid Pressure ◽  
Cartilage Defects ◽  
Loading Frequency ◽  
Liquid Pressure ◽  
Mechanical Environment ◽  
Finite Element Software ◽  
Maximum Value

COMSOL finite element software was used to establish a solid-liquid coupling biphasic model of articular cartilage and a microscopic model of chondrocytes, using modeling to take into account the shape and number of chondrocytes in cartilage lacuna in each layer. The effects of cyclic loading at different frequencies on the micromechanical environment of chondrocytes in different regions of the cartilage were studied. The results showed that low frequency loading can cause stress concentration of superficial chondrocytes. Moreover, along with increased frequency, the maximum value of stress response curve of chondrocytes decreased, while the minimum value increased. When the frequency was greater than 0.2 Hz, the extreme value stress of response curve tended to be constant. Cyclic loading had a large influence on the distribution of liquid pressure in chondrocytes in the middle and deep layers. The concentration of fluid pressure changed alternately from intracellular to peripheral in the middle layer. Both the range of liquid pressure in the upper chondrocytes and the maximum value of liquid pressure in the lower chondrocytes in the same lacunae varied greatly in the deep layer. At the same loading frequency, the elastic modulus of artificial cartilage had little effect on the mechanical environment of chondrocytes.

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