• 한국철도학회논문집
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• 제4권4호
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• pp.123-130
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• 2001

A chevron rubber spring is used in primary suspension system for rail vehicle. The chevron spring support the load carried and reduces vibration and noise in operation of rail vehicle. The computer simulation using the nonlinear finite element analysis program MARC executed to predict and evaluate the load capacity and stiffness for the chevron spring. The appropriate shape and the material properties are proposed to adjust the required characteristics of chevron spring in the three modes of flexibility. Also, several samples of chevron spring are manufactured and experimented. It is shown that the predicted values agree well the results obtained from experiment.

• Smart Structures and Systems
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• 제20권6호
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• pp.739-757
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• 2017

The main goal of this study is to investigate the hysteretic behavior of polyurethane rubber springs in compression with and without precompression. The precompression is introduced to provide rigid force in the behavior, and thereby a precompressed rubber spring can be used for a restoring element. For the goal, this study prepares nine rubber springs for three suites which are all cylindrical in shape with a hole at the center. The rubber springs in each suite have different dimensions of diameter and length but have similar shape factors; thus, they are designed to have a similar compressive stiffness. Three rubber springs from the nine are tested with increasing compressive strain up to 30% strain to investigate the behavior of the rubber springs without precompression as well as the effect of the loading strain. The nine springs are compressed up to 30% strain with increasing precompressive strain from 0 to 20% at increments of 5%. The study analyzes the effective stiffness and damping ratio of the rubber springs with and without precompression, and the rigid force of the precompressed rubber springs is discussed. Finally, this study suggests a regression method to determine the minimum required precompression to eliminate residual strain after unloading.

• 한국정밀공학회지
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• 제31권8호
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• pp.659-663
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• 2014

Manufacturing processes of industrial tire are composed of mixing, extrusion, curing, trimming and inspecting. Among them curing is the most important process in the production of industrial tire. In this study the newly developed spring vent system was designed in order to solve rubber intrusion problem inside spring vent system in the curing process. After the experiment it is concluded that rubber intrusion was caused by angled stem head part. New spring vent system was manufactured and new design of spring vent system is proper to use for industrial tire curing process.

• 한국자원식물학회지
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• 제35권3호
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• pp.399-404
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• 2022

Russian dandelion, Taraxacum kok-saghyz L.E.Rodin, is an important alternative source of natural rubber. Thus, it is critical to identify the best season for natural rubber production and harvesting for this species. In this study, T. kok-saghyz was grown in experimental fields in Korea to check the variation in rubber content with the change in the season. Studies using T. kok-saghyz plants indicate that spring and autumn are the best seasons for rubber accumulation. For several reasons, our study suggests that planting in autumn and harvesting in late spring is the best strategy for economic cultivation in Korea. Our data will be useful for future commercialization of rubber production from T. kok-saghyz because time will be saved if the plant is grown and harvested in the optimum season.

• Structural Engineering and Mechanics
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• 제24권1호
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• pp.31-50
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• 2006

This paper deals with the mechanical behaviour of the thin-walled cylindrical air-spring shell (CAS) made of rubber-textile cord composite (RCC) subjected to different types of loading. An orthotropic hyperelastic constitutive model is presented which can be applied to numerical simulation for the response of biological soft tissue and of the nonlinear anisotropic hyperelastic material of the CAS used in vibroisolation of driver's seat. The parameters of strain energy function of the constitutive model are fitted to the experimental results by the nonlinear least squares method. The deformation of the inflated CAS is calculated by solving the system of five first-order ordinary differential equations with the material constitutive law and proper boundary conditions. Nonlinear hyperelastic constitutive equations of orthotropic composite material are incorporated into the finite strain analysis by finite element method (FEM). The results for the deformation analysis of the inflated CAS made of RCC are given. Numerical results of principal stretches and deformed profiles of the inflated CAS obtained by numerical deformation analysis are compared with experimental ones.

• 대한기계학회논문집A
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• 제25권4호
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• pp.602-609
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• 2001

This paper is concerned with the orthotropic problem of diaphragm-type air springs which consist of rubber linings, nylon reinforced rubber composite and bead ring. The analysis is carried out with a finite element method developed to consider the orthotropic properties, geometric nonlinearity using four-node degenerated shell element with reduced integration. Physical stabilization scheme is used to control the zeroenergy mode of the element. The analysis includes an inflation analysis and a lateral analysis of an air spring for the deformed shape and the spring load with respect to the vertical and l ateral deflection. Numerical results demonstrate the variation of the outer diameter, the fold height, the vertical force and the lateral force with respect to the inflation pressure and the lateral deflection.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.468-475
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• 2000

An air spring was accepted for rail vehicle secondary suspension to reduce and absorb tile vibration and the noise. The air spring for the electric railway was developed with domestic technology, which consisted of a cord reinforced rubber bellows, a upper plate, a lower plate and a stopper rubber spring The fatigue test was conducted in laboratory by using servo hydraulic fatigue testing system to verify the durability. And to guarantee the adaptation of this air spring, the ride comfort and the air pressure variation were measured in train test on Boondang line.

• 대한소아치과학회지
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• 제32권3호
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• pp.525-530
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• 2005

정중이개란 상악 중절치 사이의 치간이개를 말한다. 이는 혼합 치열기에서 ugly ducking stage에 흔히 관찰할 수 있으며 일반적으로 견치가 맹출하면서 자연적으로 소실되므로 꼭 치료가 필요한 것은 아니다. 그러나 견치 맹출 후에도 정중이개가 2mm이하로 계속 존재하거나 견치 맹출 전이라도 3mm이상의 정중이개가 존재하는 경우에서는 치료의 적응증이 될 수 있다. 특히 후자의 경우 심미적인 면에서 뿐만 아니라, 이로 인해 측절치와 견치의 맹출공간이 부족해지는 문제가 발생하므로 교정치료가 권장된다. 정중이개 치료시 사용되는 장치물은 finger spring 등을 이용한 가철성 장치물과, 교정용 band, tube, bracket 등을 부착시켜 rubber elastics이나 coil spring 등을 사용하는 고정성 장치물로 나뉘어진다. 그러나 정중이개의 치료를 위해 rubber band를 band, tube, bracket 등과 같은 적절한 부가장치 없이 사용하면 rubber band가 치근은 따라 치은 하방으로 이동하게 되고 치주 인대를 파괴하며 치근단 부위에 이르러 치아동요, 치아정출 및 탈락 등 치아에 치명적인 손상을 입힐 수 있다. 본 증례는 정중이개의 치료를 위해 부적절하게 rubber band를 사용하여 외상을 받은 치아를 관찰하여 다소의 지견을 얻었기에 이를 보고하는 바이다.

• Journal of Biosystems Engineering
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• 제29권5호
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• pp.385-394
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• 2004

The objectives of this study were to investigate the effectiveness of rubber as an engine mount of walking-type cultivators and to determine its optimal spring constant and damping coefficient using a dynamic simulation of the engine mount system. Four different types of rubber mounts were tested to determine their spring constants and damping coefficients, and the best type was selected for the isolation of the engine vibrations transmitted to the handle. The total vibration levels transmitted to the handle when the rubber mounts weren't installed were 17.52 $m/s^2$. The total vibration levels transmitted to the handle when the rubber mounts were installed were 10.69 $m/s^2$ for Stripe 1, 11.33$m/s^2$ for Stripe 2, 10.92$m/s^2$ for Stripe 3 and 14.19$m/s^2$ for Hive, respectively, resulting in an average of $30\%$ reduction when compared with that without the engine mount. A dynamic model of the cultivator's engine-mount system and its simulation program were developed and verified. A method was proposed to determine the optimal spring constant and damping coefficient of the engine-mount system. It was found from the simulation that a spring constant of 4,100 kN/m and the largest damping coefficient were the most effective for the vibration isolation.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1078-1088
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• 2012

Recently, the vibration and structure-borne noise induced by passing trains are of great concerns, and the floating slab track is highlighted as one of most efficient alternatives to reduce the railway vibration. However, due to the non-linearity and viscosity of rubber spring used in the floating slab track, its dynamic behavior is very complex. In this study, therefore, to simulate the dynamic behavior of floating slab track with a better accuracy, a nonlinear viscoelastic rubber spring model that can be incorporated in commercial finite element analysis codes has been proposed. This model is composed of a combination of elastic spring element, friction element and viscous element, and termed the "generalized friction viscoelastic model(GFVM)". Also, in this study, the method to determine the model parameters of GFVM based on Berg's 5-parameter model was presented. The results of the finite element analysis with this rubber spring model exhibit very good correlation with the test results of a laboratory mock-up test, and the feasibility of GFVM has been verified.