• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.65-65
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• 2004

스프링은 변위에 상응하는 에너지를 저장하는 기계 요소로서 다양한 분야에 적용되고 있으며, 나선형(helical) 스프링, 와선형(spiral) 스프링, 비틀림 막대, 디스크(disk) 스프링, 판(plate) 스프링, 일정 하중(constant force) 스프링 둥 다양한 종류가 있다. 근래 많이 사용되는 LCD 모니터 가운데 일부는 경사(tilt), 회전(pivot), 방향 전환(swivel) 등 모니터의 각도 변화가 가능하도록 제작되며, 이러한 각도 변화시 사용자가 적절한 반력을 느끼도록 인간 공학적으로 설계되어 있다.(중략)

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.1-10
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• 2022

In this study, to evaluate the possibility of using a steel spring as a displacement-dependent damping device, tensile loading and cyclic loading tests were performed. The main experimental variables were the type of steel (SAE9254 and SS275), the spring constant (700 N/mm, 1,000 N/mm, and 1,400 N/mm), and the presence or absence of heat treatment for SAE9254. As a result of the tensile test, the ratios of the measured spring constant to the design spring constant of the steel springs made with SAE9254 ranged from 1.08 to 1.13, while the ratios of the design spring constant and the measured spring constant of the steel springs made with SS275 ranged from 0.86 to 0.97. After yielding, the slope values of the load-displacement curve of the SAE9254 with/without heat treatment were about 240~251 N/mm and 92 N/mm, respectively, but the slope values of the load-displacement response of SS275 were almost zero. According to the uniaxial cyclic loading test results, all specimens were satisfied with three conditions for a displacement-dependent damping device in KDS 41 17 00 (2019): the maximum force and minimum force at zero displacement, the maximum force and minimum force at the maximum displacement, and the energy dissipation capacity. In addition, the equivalent damping ratios of steel springs made with SAE9254(non-heat treatment) and SS275 were approximately 2.8 times and 1.9 times greater, respectively, than that of steel springs made with SAE9254.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.299-300
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• 2022

구조물의 내진보강방법 중에서 가장 널리 이용되는 방법인 강재 이력형 감쇠장치는 수평하중에 대한 응력-변위 곡선을 이용하여 지진 에너지를 소산시키는 방법인데, 이 경우 편심하중 등에 의해서 부재가 면 외 방향으로 거동하여 응력-변위곡선이 불규칙하여 그 결과의 신뢰성이 떨어지는 경우가 있다. 이러한 형상을 방지하기 위해서는 별도의 채널(Channel)을 시공하는 불편함을 감수해야 하며, 또한 수평력이 반복적으로 작용할 때 그 효과를 장담할 수 없는 문제점이 있다. 본 연구에서는 강재 스트립과 스프링을 결합한 댐퍼를 고안하여 스프링은 탄성변형을, 강재 스트립은 소성변형을 받게 하는 혼합형 댐퍼를 개발하고자한다. 여기서, 스프링은 복원력으로 작용하여 반복하중에 대한 저항성을 키우고 강재 스트립의 하중변위 곡선을 규칙적으로 하는 역할을 수행하게 되며 에너지 소산량을 계산할 때 편리함과 정확도를 높이고자 한다. 강재 스트립의 폭과 길이는 일정하지만 두께를 변화시켜서 5종류를 선택하였으며, 댐퍼 1개당 3개의 스트립을 정삼각형 형태로 배치하고 그 중심에 상당한 강성을 갖는 스프링을 갖는 형태로 제작하였다. 댐퍼 시험체는 5개를 제작한 후, 이 댐퍼를 구조물에 배치하였을 때의 지진에 대한 에너지 소산량과 부재력을 검토하여 댐퍼의 안전성(Safety)를 검증하고자 한다.

• Journal of Power System Engineering
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• v.7 no.4
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• pp.49-54
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• 2003

스프링은 가장 널리 이용되어지고 있는 기계요소이다. 본 논문에서는 원추형 코일스프링의 강성을 구하기 위하여, 빔요소를 이용한 유한요소법을 사용하였다. 가상일의 법칙을 이용하였고, 코일스프링의 하중벡터를 압축 분포하중으로 대체하였다. 하중의 증가에 의한 절점에서의 변위는 유한요소법를 이용하여 계산하였다. 단계법으로 결점의 변위를 중첩하여 전체 강성행렬을 구하였다. 유한요소법에 의한 해석치는 실험치와 잘 일치하였다. 본 논문에서 제시한 프로그램을 사용하여, 스프링 강성과 응력을 예측할 수 있을 것으로 사료된다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.1 s.71
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• pp.85-92
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• 2006

This paper investigates critical loads of the tapered Beck's columns with clamped and spring supports, subjected to a subtangential follower force. The linearly tapered columns with the solid rectangular cross-section is adopted as the column taper. The differential equation governing free vibrations of such Beck's columns is derived using the Bemoulli-Euler beam theory. Both divergence and flutter critical loads are calculated from the load-frequency curves which are obtained by solving the differential equation. The critical loads are presented as functions of various non-dimensional system parameters: the taper type, the subtangential parameter and the spring stiffness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.226-234
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• 2021

The objective of this study is to establish the fundamental design data for axial load-displacement relationship under axial monotonic or cyclic responses of seismic damping·isolation (SDI) units developed for ceiling structures. The main parameters include the installation of a spring, the number of rubber layer, prestress stress of bolts for connector between the spring and rubbers, and loading type. Test results showed that SDI units with a spring in the core and higher prestress stress of bolts tended to be higher stiffness at the ascending branch and more ductile behavior at the descending branch. This trends more notable for the specimens under monotonic load rather than cyclic loads. Consequently, the energy dissipation of SDI unit can be optimally designed with the following conditions: installation of a spring within 3-layer rubbers and prestress applied to the bolts at 10% of their yielding strength . When compared with the experimental tension capacity of the developed SDI units, the predictions by JIS B 2704-1 and KDS 31 00 are conservative under monotonic loading but higher by approximately 10% under cyclic loading.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.112.2-112.2
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• 2005

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.11
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• pp.1099-1104
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• 2012

The study investigates the mechanical deformation of a newly developed screwless omega-wire dynamic system for stabilization of the spine. The omega-wire spring stabilization system was tested under tension, compression, and dynamic compressive fatigue loads. In addition, its bending deformation was compared to that of a spiral-wire spring system using FEA. A model whose hanger inter-center distance is 60 mm showed an ultimate tensile stress of 3981.7 N at a displacement of 3.61 mm and an ultimate compressive load of 535.6 N at a displacement of 2.16 mm. Under fatigue loading of 5 Hz with 10 N/1 N, it did not show any failure over 5 million cycles, and the displacement was restricted to 8-9 mm. In the FEA, the omega-wire spring system showed more flexible bending features than did the spiral-wire spring system.

• Composites Research
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• v.15 no.4
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• pp.17-22
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• 2002

Small diameter composite helical springs (CS) are developed using a hot plated mold for reinforcement of common optical fiber jumper cord (OJC). The outer diameters of the springs are about 2 ~ 3mm. These springs are inserted into the OJC to protect the damage of an optical fiber from the sudden lateral load. Two types of CS, Yarn type (Y-type) and Band type (B-type), are manufactured to compare the effectiveness for the damage protection. The experimental works were conducted to check the effect of the CS covered around OJC on the mechanical and optical properties. Experimental observations show a considerable effect on the flexural resistance, hence slowing down the deterioration of the optical power by the internal damage of the fiber. Obtained main results are as follows: (1) Y-type CS has better protection abilities to lateral loading than B-types. (2) Compared with bare OJC, CS-OJC has less power loss under the loading. (3) OJC covered with the composite coil spring has a possibility for a practical usage with full fruits.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.347-354
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• 2012

The recovery force and displacement occur due to the phase transformation from the martensite phase to the austenite phase induced by the mechanical loading or thermal loading. These recovery force and displacement depend on an initial geometrical configuration of SMAs and loading conditions. Although the SMAs generally generates large recovery forces, the sufficient recovery displacement cannot be expected without a proper design strategy. The functionality of SMAs is limited due to the unbalance between the large recovery force and the small recovery displacement. This study suggests the double coil SMA spring in order to amplifying the recovery displacement induced by the phase transformation. By predicting the recovery displacement of doble coil SMA springs and one coil SMA springs induced by thermal loading, we show that the double coil SMA spring not only mitigate the unbalance of performance but also have a large recovery displacement for its recovery force than one coil SMA spring.