• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.83-84
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• 2013

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.3
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• pp.193-201
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• 2023

In this study, a nonlinear truss finite element is developed to analyze structures with negative Poisson effect-induced tensile buckling. In general, the well-known buckling phenomenon is a stability problem under a compressive load, whereas tensile buckling occurs because of local compression caused by tension. It is not as well-known as classical buckling because it is a recent study. The mechanism of tensile buckling can be briefly explained from an energy standpoint. The nonlinear truss finite element with a torsional spring is formulated because the finite element has not been reported in the literature yet. The post-buckling analysis is then performed using the generalized displacement control method, which reveals that the torsional spring plays an important role in tensile buckling. Structures that mimic a negative Poisson effect can be constructed using such post-buckling behaviors, and one of the possible applications is a mechanical switch. The results obtained are compared to those of analytical solutions and commercial finite element analysis to assess the validity of the proposed finite element model. The numerical results show that the developed finite element model could be a viable option for the basic design of nonlinear structures with a negative Poisson effect.

• Transactions of Materials Processing
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• v.13 no.1
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• pp.15-20
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• 2004

In order to evaluate spring-back behavior in automotive sheet forming processes, a panel shape idealized as a double S-rail has been investigated. After spring-back has been predicted for double S-rails using the finite element analysis, results has been compared with experimental measurements for three automotive sheets. To account for hardening behavior such as the Bauschinger and transient effects in addition to anisotropic behavior, the combined isotropic-kinematic hardening law based on the Chaboche type model and a recently developed non-quadratic anisotropic yield function have been utilized, respectively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.4
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• pp.48-53
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• 2005

This research is materialized the mechanism of a interlocking elevator device to meet with customer's requirement demanding a variety of function. On this suitably theoretical translation and by considering of material significance of the most factor's tension spring and torsion spring, it's compared and reviewed the stress's calculation according that SWC and SWPB applied differently. And also that is approved through actual experiment. Out of a variety of feasible movement. Torque Balance is materialized by combination of tension spring, torsion spring and disk spring. So that application of 3 factors for optimal design is very important factor. In future, this research thesis make sure to play a highly role for application and improvement mechanically in various industry sector out of materializing interlock.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1831-1838
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• 1991

The deformation of coil spring with noncircular section, which is used in the engine valve of automobiles under the applied load is usually accompanied by sectional warping and additional displacements of geometric center. In this study the isoparametric beam element formulations are modified and expanded to consider these two effects. To verify these formulations, simple torsion tests are made and compared with the analysis results. For the case of the zero-pitch spring, the stress distributions of oval and circular section are coincided with those of the analysis using the solid elements. Cylindrical coil springs with oval section are analyzed. These results are agreed with those of Nagaya.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1192-1198
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• 2011

Design routines of a torsional spring-viscous damper for a 1800 kW four cycle diesel engine-generator system are described. Modal techniques for system normalization and optimal equations for damper design are used to obtain proper design parameters of the damper. A prototype damper is manufactured according to the described design process and its two design parameters, stiffness and damping, are evaluated experimentally by torsional actuator test and free decay test. Experimentally obtained values of stiffness and damping coefficients showed good agreements with the designed values of the prototype damper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.100-105
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• 1994

본 연구에서는 변속기 중립상태에서 클러치 설계 인자인 비틀림 스프링과 건마찰에 의해서 클러치에 나타나는 히스테리시스, 그리고 클러치 디스크의 정적처짐을 발생시키는 드래그토크(drag torque)가 클러치의 동적인 거동과 기어래틀에 미치는 영향을 분석하고자 한다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.10
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• pp.902-908
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• 2013

The input torque ripple induced by combustion engines is a significant source of NVH(noise, vibration and harshness) problem in automotive transmissions. Because this torque fluctuation is primarily transmitted to the input shaft of automotive powertrains(e.g., automatic transmissions) when the lock-up clutches are closed, a torsional damper with helical springs is generally inserted between engine and transmissions to isolate the input vibratory energy, which is essential for the passenger comfort. The torsional vibration isolator exhibits frequency ranges in which there is low vibration transmissibility. However, the isolation performance is currently evaluated through the static torsional spring characteristics. In this study, the transmissibility of torsional spring dampers, essential dynamic performance index for vibration isolator, is first experimentally evaluated.

• Journal of KSNVE
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• v.8 no.5
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• pp.856-861
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• 1998

Several reactor system components, such as heat exchange tubes, fuel fins, controlrods, and various instruments are beam-like components. This study presents a simple solution method for calculating the natural frequencies and modes of beams supported by linear and torsional springs and attached concentrated mass and rotational inertia at some intermediate points. For a general multi-span beam, theoretical method is proposed to analyze the exact solution about vibrational characteristics with respect to the nondimensional parameters. And the results obtained using the numerical models are presented and discussed.

• The Safety technology
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• no.175
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• pp.15-17
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• 2012

한 대의 자동차가 완성되기 위해서는 약 2~3만 개에 가까운 부품이 들어간다. 자동차의 심장인 엔진부분은 물론 자동차의 외형을 이루는 몸체, 각종 전기장치 등을 만들기 위해서 갖가지 부속품이 필요한 것이다. 이들 부품 가운데 특히 많이 쓰이는 것이 압축코일, 비틀림코일, 태엽 등의 각종 스프링이다. 이와 같은 스프링을 제작하는 기업은 많지만 그중에서도 (주)디지에쓰는 업계에서 명성이 자자하다. 지난 1974년 설립돼 현재 40여 명이 근무하고 있는 작은 회사이지만 기술연구소를 설치 운영하고 있을 정도로 연구개발에 힘써 온 결과 남부럽지 않은 기술력을 갖게 됐기 때문이다. 2010년에 중소기업청으로부터 기술혁신형 중소기업으로 선정된 것이 이를 입증하고 있다. 작지만 강한 기업이라는 수식어가 전혀 어색하지 않은 것이다. (주)디지에쓰가 명성을 얻고 있는 데에는 또 다른 이유가 있다. 바로 철저한 안전관리를 바탕으로 5년 연속 무재해를 이어가고 있기 때문이다. 우리나라의 산업재해 가운데 80% 이상이 50인 미만 소규모 사업장에서 발생하고 있다는 점에 비춰보면 이곳의 무재해 기록이 갖는 의미는 남다르다고 할 수 있다. 철저한 안전관리를 바탕으로 성장을 거듭하고 있는 (주)디지에쓰를 찾아가 봤다.