• Structural Engineering and Mechanics
• /
• v.82 no.4
• /
• pp.435-444
• /
• 2022

This study proposes a novel longitudinal self-centering earthquake resistant system for reinforced concrete (RC) continuous bridges by using superelastic shape memory alloy (SMA) reinforcement and friction dissipation mechanism. The SMA reinforcing bars are implemented in the fixed piers to provide self-recentering forces, while the friction dampers are used at the movable substructures like end abutments to enhance the energy dissipation of the bridge system. A reasonable balance between self-centering and energy dissipation capacities should be well achieved by properly selecting the parameters of the SMA rebars and friction dampers. A two-span continuous bridge with one fixed pier and two abutments is chosen as a prototype for illustration. Different longitudinal earthquake resistant systems including the proposed one in this study are investigated and compared. The results indicate that compared with the designs of over-dissipation (e.g., excessive friction) and over-self-centering (e.g., pure SMAs), the proposed system with balanced design between self-centering and energy dissipation would perform satisfactorily in controlling both the peak and residual displacement ratios of the bridge system.

• Structural Engineering and Mechanics
• /
• v.89 no.4
• /
• pp.411-420
• /
• 2024

The purpose of this research was to investigate the cyclic behavior of the D-shaped dampers (DSD). Similarly, at first, the numerical model was calibrated using the experimental sample. Then, parametric studies were conducted in order to investigate the effect of the radius and thickness of the damper on energy dissipation, effective and elastic stiffness, ultimate strength, and equivalent viscous damping ratio (EVDR). An analytical equation for the elastic stiffness of the DSD was also proposed, which showed good agreement with experimental results. Additionally, approximate equations were introduced to calculate the elastic and effective stiffness, ultimate strength, and energy dissipation. These equations were presented according to the curve fitting technique and based on numerical results. The results indicated that reducing the radius and increasing the thickness led to increased energy dissipation, effective stiffness, and ultimate strength of the damper. On the other hand, increasing the radius and thickness resulted in an increase in EVDR. Moreover, the ratio of effective stiffness to elastic stiffness also played a crucial role in increasing the EVDR. The thickness and radius of the damper were evaluated as the most effective dimensions for reducing energy dissipation and EVDR.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2000.04a
• /
• pp.308-318
• /
• 2000

This paper introduces the acceptance criteria for reinforced concrete moment frames based on structural testing of ACI in preparing and proposes criteria for acceptable limiting drift and energy dissipation ratios of reinforced concrete shear walls for structural testing. Limiting drift and energy dissipation ratios were examined for tests on shear walls having ductile type failures. Test data were analyzed and compared to results for a suggested acceptance criteria that involves a limiting drift that is a function of aspect ratio a limiting energy dissipation ratio that is a function of displacement ductility and damping.

• ETRI Journal
• /
• v.33 no.1
• /
• pp.140-143
• /
• 2011

Recent test data compression techniques raise concerns regarding power dissipation and compression efficiency. This letter proposes a new test data compression scheme, twin symbol encoding, that supports block division skills that can reduce hardware overhead. Our experimental results show that the proposed technique achieves both a high compression ratio and low-power dissipation. Therefore, the proposed scheme is an attractive solution for efficient test data compression.

• Journal of the korean Society of Automotive Engineers
• /
• v.5 no.1
• /
• pp.89-93
• /
• 1983

This paper describes on experimental investigation into the heat dissipation of Diesel engine, placing emphasis on the variations of compression ratio and cooling water temperature. The engine used for this test was a vertical single-cylinder four-cycle type, having a direct injection. Engine performance and heat transfer rates was tested under the compression ratio 14.3 and 17.4. In this study, the results showed that output and transfer rates of engine decrease in accordance with the decrease of compression ratio. The effect of cooling water temperature and injection delay of fuel on the heat dissipation brings about the decrease of heat transfer rates from cylinder to cooling water.

• Journal of Ship and Ocean Technology
• /
• v.1 no.1
• /
• pp.48-56
• /
• 1997

This paper deals with the energy dissipation of ductile metal plate due to cutting. By using nondimensional analysis, we present that the dissipation energy of tearing behaviour can be formulated as a function of slenderness ratio expressed by cutting length, yield stress, plate thickness and elastic modulus. The validity of the proposed formula for Al-alloy, copper and mild steel is demonstrated by comparing the proposed formula with experimental results, which are shown in good agreements except for thick mild steel plate.

• East Asian mathematical journal
• /
• v.22 no.2
• /
• pp.171-188
• /
• 2006

We consider the problem of an optimal control of the wave equation with a localized nonlinear dissipation. An optimal control is used to bring the state solutions close to a desired profile under a quadratic cost of control. We establish the existence of solutions of the underlying initial boundary value problem and of an optimal control that minimizes the cost functional. We derive an optimality system by formally differentiating the cost functional with respect to the control and evaluating the result at an optimal control.

• Fibers and Polymers
• /
• v.5 no.2
• /
• pp.151-155
• /
• 2004

Cold plasma of $O_2$ or Ar was irradiated on hydrophobic Kapton surface to attenuate or remove the electrostatic potential. A measurement on charge dissipation speed clarifies the obscure effect of plasma. These consequences reveal that $O_2$ plasma etching is more effective than Ar plasma. After 30 days, the dissipation speed of accumulated charge on initially etched sample has not changed under summer season.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.133-134
• /
• 2010

An experiment was carried out to evaluate energy dissipation capacity and velocity dependent characteristics of the viscous damper. From the experiment, it was found that the viscous damper showed velocity dependent characteristics and excellent energy dissipation capacity.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.6
• /
• pp.128-133
• /
• 1994

This paper proposes a new TTL-to-CMOS converter which has low power dissipation. This converter has no static power dissipation for typical TTL output voltage levels. The simulatio result shows that the power dissipation is reduced to about 1/20 of conventional level converter using CMOS inverters. It also has hysteresis due to the positive feedback which makes the converter noise immune. The logic threshold voltages in the hysteresis characteristic can be optimized by changing the size ratios of the transistors.