The seismic retrofits of existing structures have been focused on the control of structural responses which can be achieved by providing displacement capacity through inelastic ductile action at supplemental devices. Due to their hysteretic characteristics, it is expected to sustain damage through repeated inelastic behaviors including residual deformation which might increase repair costs. To solve such drawbacks of existing yielding devices, this study proposes a self-centering disc spring brace that sustains large axial deformation without structural damage while providing stable energy dissipation capacity. The hysteretic behaviors of suggested brace are first investigated based on the quasi-static cyclic test procedure. Experimental results present the effective self-centering behavior and an analytical model is then suggested in order to reasonably capture the flag-shaped hysteretic behavior of the disc spring brace.

In electric vehicles, the core is a secondary cell battery. Raw material is pulverized by the grinding disc in the Classifier Separator Mill (CSM) and rises through the Classifier Wheel. Both require characteristics to withstand high-speed rotation, including abrasion, corrosion, and shock. Our study analyzes the impact of RPM and heat source on temperature, convergence, and durability. In conclusion, high heat increases flow, while high RPM reduces the maximum temperature but may harm durability. Proper RPM settings enhance durability.

Diesel engine is used many industrial fields such as ship, power plant and big-sized vehicles and so on. Roto cap is one of the parts of system of intake and exhaust valve. Roto cap consists of body, disc spring, spring & steel ball, retainer and stop ring. Disc spring is known as taking cyclic load and cyclic load leads to fatigue damage. This study aims to investigate the stability of disc spring due to fatigue damage. As the results, the fatigue life of disc spring according to cylic load could be predicted using fatigue analysis. Consequently, disc spring showed the stability of about 1.7~2 times for criterion load of 1370N.

In turbopump type liquid rocket engines, ignition and starting are known to be the most unstable and risky section among all operating sections of the projectile. The operation of the liquid rocket engine is the process of ignition and combustion of the main combustor after the turbo pump is driven into a stable section due to the turbine driving of the turbo pump and the ignition and combustion of the gas generator by the pyro starter. In this process, the driving of related components directly influences each other, so each component must be operated with sufficient reliability. In particular, if the igniter does not supply sufficient ignition energy at a predetermined time, an explosion may occur due to stagnation of the fuel/oxidant mixture, so reliability is more important. In this study, the fracture analysis of the gas generator igniter rupture disk according to the shape was performed using computational analysis. As a result, comparative analysis was performed to obtain the optimal dimensions according to each variable condition.

The brake system drives the vehicle by converting the kinetic energy into thermal energy. The heat energy generated during the braking process increases the temperature of the structure. It causes thermal deformation due to overheating and causes cracks, noise, and vibration that degrade performance. However, it is not possible to fundamentally prevent the temperature rise of the brakes. There is a need for research on improving the heat dissipation performance by improving the shape of the brake. Therefore, this study analyzed the concentrated stress caused by overheating of the brake disc. In order to improve the performance of the disk, shape optimization design was performed. For stress and thermal analysis, the analysis was conducted using the finite element program ANSYS Transient Thermal and Structural tools. PIAnO (Process Integration and Design Optimization) was used to perform optimal design. In the formulation of the optimum design, the stress was minimized by satisfying the constraints. This study intends to present a new brake disc model by performing perforated shape and arrangement.

Rotor disc (로터 디스크)는 중대형 유조선에서 유류를 하역하는 장치인 COPT (Cargo Oil Pump Turbine)의 터빈을 고속으로 회전시키는 핵심 부품이다. 이 rotor disc는 중심 shaft에 여러 개의 turbine을 원주상으로 배열하고 체결하여 제작한다. 현재의 제작 방법으로는 turbine blade를 배열하고 shroud 덮개로 연결하여 riveting 방식으로 체결한다. 이런 고전적인 방법은 blade pitch의 불균일은 물론 작업 시 오류로 인해 blade에 손상이 가는 경우가 있다. 이러한 단점을 해결하기 위해서는 조립식의 rotor disc를 설계하여 제작방식을 변경해야 한다. 설계뿐만 아니라 조립식의 disc가 구조적으로 안정한지를 평가해야 한다. 본 논문은 blade의 설계와 이를 조립하였을 때에 구조안전성을 평가하기 위해 구조 해석하여 그 안전성을 검증 한다.

The purpose of this research is to reduce the weight of the brake system of vehicles and to increase braking performance and its durability and to shorten the stopping distance. The plans for light-weight vehicles are to develop light weight material itself which possesses superior properties and another way is to improve the manufacturing method of materials which have the better mechanical properties. And the materials used for this are aluminum alloy, magnesium alloy, titan alloy, steel, other metals, plastic, ceramic materials etc. In this research, aluminum is used for the main body of the break to reduce the weight of the brake and cast iron(SCM4), stainless steel(SUS304) and titan alloy(Ti Gr2) are used for the outer ring shape plate and assembled with bolts. Dynamometer test are braking performed on the brake disc. Based on the test results, stainless steel(SUS304) is optimized for the light-weight brake disc.

A numerical approach for ventilated disc brake with holes is carried out to investigate the effect of holes on the heat transfer characteristics. The numerical simulation code STAR-CCM+ is utilized to calculate flow and temperature fields with polyhedral meshes. The steady state results show that the holes make the flow velocity on the outer surface increasing, which induce the improvement of convective heat transfer on the outer surface. In the ventilated channel with holes, the convective heat transfer can be reduced due to the inflow of hot air through holes. In unsteady state, the disc has reached the highest temperature in 1,8s since the brake was engaged. The surface of disc without holes has maximum temperatures along the ventilated channels, while the surface temperatures of dis with holes are uniform.

In this paper, the relationship between the frequency split and the mode-coupling in the disc doublet mode, which is expressed according to the pattern of the surface of the disc, is utilized by using of 3 types(Chaos, Vent-hole, Normal). As the frequency split between the doublet mode disc that is expressed in the model through the interpretation is larger, and analogy through interpretation mode-coupling instability also lower. Vent-hole, which has a relatively large frequency split of disc doublet mode in 3 types(Chaos, Vent-hole, Normal) model, showed a large value of critical coefficient of friction in which mode-coupling instability is expressed. In addition, it was confirmed by analysis that the Vent-hole had a relatively large frequency split than the other models by analyzing the change in contact stiffness. It can be concluded that the larger the frequency split of the disc doublet mode, the lower the instability due to the mode-coupling.

대형 선박의 Cargo Oil Pump Driving Steam Turbine 내에 설치되는 COPT (Cargo Oil Pump Turbine)는 유조선에 탑재되어 탱크에 저장되어 있는 유류를 다른 저장소로 하역하는데 사용되는 필수 장치이다. 펌프 터빈의 로터를 고속으로 회전시켜 유류를 고속으로 이송하는 역할을 하는데, COPT의 Rotor Disc는 터빈의 로터를 고속으로 회전 시키는 주요 핵심부품이다. 로터 디스크는 inner ring에 터빈 블레이드를 조립하고 원주방향의 끝 부분에 shroud 커버를 조립하여 블레이드의 테논을 리벳팅으로 마무리하고 체결하여 고속회전 시 안전성을 담보한다. 리벳팅은 오랜 수작업의 전통 체결방식으로서, 가해지는 힘의 정도에 따라 리벳 헤드부분이 깨지거나 변형되어 크랙이 발생할 수 있으며 또한 블레이드의 중량이 불균형되어 Balancing에 문제가 생길 수도 있다. 또한 오랜 수작업으로 인해 작업자의 근골격계 질환이나 직업병 유발 및 산재사고의 위험에 처할 수 도 있다. 본 연구에서는 shroud 커버가 없는 블레이드 형상을 설계하여 리벳팅 작업을 제거한 로터 디스크를 개발한다. 블레이드의 설계 시 구조안전성을 평가하고 설계 안전율을 점검한다. 설계형상을 대상으로 피로수명을 분석하고 수명을 예측하여 새로운 로터 디스크가 장착되어도 사용상의 안전성이나 내구성을 보장할 수 있도록 한다.

The brake systems are composed of brake disc, brake pad and caliper and, these three parts play an important role for braking. In this study, heat fluid analysis is conducted for five different ventilated disc models, and two piece brake disc model separated in rotor and housing is used. In this case, each model has a different number of holes and vent shape. The basic heat flux and braking power equations are applied for the heat fluid analysis. The cooling performance with/without the braking operation is also analyzed for given five models where the material properties and boundary conditions are set to be identical. From our analysis results, it is found that the number of disc holes and ventilated pins strongly influences on the cooling performance.

본 연구에서는 디스크 링 형태에 패터닝된 박막을 적층시킨 모듈의 분리특성을 규명하고자 투과실험을 수행하였다. 먼저, 본 연구에서 자체 제작한 5가지 형태의 디스크 필터의 순수 투과도를 측정하였으며 그 값은 0.25 내지 2.24L/m2·hr·bar이었다. 0.1 wt% 카올린 수용액을 투과시키면 순수 투과율이 가장 높은 모듈의 투과유속이 가장 높았고, 순수 투과율이 가장 낮았던 모듈의 카올린 투과유속이 가장 낮게 나타났다. 그러나 모든 모듈의 카올린 투과유속이 순수 투과율에 비례하지는 않았다. 또한 0.1 wt% 수용액으로 장시간 운전하기 위하여 디스크 필터 모듈 1에 주기적으로 역세척을 실시하였으며 가장 효율적인 운전조건은 투과시간 8분, 역세척 2분 주기임을 확인하였다.

The main object of this study is to investigate the collection characteristics of wet-type rotating porous disk system experimentally. The experiment is carried out to analyze the pressure drop and collection efficiency for the present system with the experimental parameters such as system inlet velocity, stage number, tube diameter, inlet concentration, etc. In results, for the present system, at 5 stage and υin=1.8 m/s, the pressure drop becomes significantly lower as 64 mmH2O in comparison with that of the conventional wet type scrubber (Venturi scrubber, over 250 mmH2O). The collection efficiencies increase with higher inlet velocity showing 92, 95.7, 98.4%, while SO2 removal efficiencies decrease with increment of inlet velocity as 80, 65, 50% at υin=1.08, 1.44, 1.8 m/s and tube diameter Dt=10 mm, respectively. The present system is to be considered as an effective compact system for a simultaneous removal of particle/gas phase pollutants from marine diesel engines.

The heat generated in contact type braking system can cause an unacceptable braking performance. Thermal behavior of ventilated disk brake system is presented in this paper. The temperature and velocity fields of 3-D unsteady simulated model are obtained using a software package "FLUENT". The numerical results show that there exits a temperature nonuniformity between the disk faces contacting with pads. The conduction rate through the disk and pad is calculated and the effect of material conductivity is also investigated.

이 논문에서는 근래에 널리 사용되는 면진 장치인 폴리우레탄 스프링 복원형 디스크 받침의 동적거동에 영향을 미치는 구성재료의 인자에 대한 분석을 수행한 후, 그 결과를 이용하여 받침의 거동을 예측하여 거동 시험결과와 비교하였다. 여기서 동적거동에 영향을 미치는 인자로는 속도와 접촉압력에 따라 변하는 불소수지판(PTFE, PolyTetraFluoroEthylene, 폴리테트라플루오로에틸렌)의 마찰계수와 변형률에 따라 변화하는 폴리우레탄 스프링의 탄성계수가 고려되었다. 불소수지판은 W-PTFE virgin 제품을 사용하였고, 폴리우레탄 스프링은 직접 제작한 것을 사용하였다. 접촉압력, 속도에 따른 마찰계수 변화와 변형률에 따라 변하는 폴리우레탄 스프링의 탄성계수를 모사하는 식은 각각의 시험결과로부터 역추정 하여 사용하였다. 동특성 영향인자를 고려한 거동의 예측 결과는 동특성이 고려되지 않고 정적 인자만을 고려한 예측 결과보다 시험결과와 더 적절한 일치성을 보여주었다.