• Title/Summary/Keyword: Dynamic Dissipation

Search Result 345, Processing Time 0.022 seconds

Quasi-Static and Shaking Table Tests of Precast Concrete Structures Utilizing Clamped Mechanical Splice (가압고정 기계적이음을 활용한 프리캐스트 콘크리트 구조물의 준정적 및 진동대 실험)

  • Sung, Han Suk;Ahn, Seong Ryong;Park, Si Young;Kang, Thomas H.-K.
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.27 no.1
    • /
    • pp.37-47
    • /
    • 2023
  • A new clamped mechanical splice system was proposed to develop structural performance and constructability for precast concrete connections. The proposed mechanical splice resists external loading immediately after the engagement. The mechanical splices applicable for both large-scale rebars for plants and small-scale rebars for buildings were developed with the same design concept. Quasi-static lateral cyclic loading tests were conducted with reinforced and precast concrete members to verify the seismic performance. Also, shaking table tests with three types of seismic wave excitation, 1) random wave with white noise, 2) the 2016 Gyeongju earthquake, and 3) the 1999 Chi-Chi earthquake, were conducted to confirm the dynamic performance. All tests were performed with real-scale concrete specimens. Sensors measured the lateral load, acceleration, displacement, crack pattern, and secant system stiffness, and energy dissipation was determined by lateral load-displacement relation. As a result, the precast specimen provided the emulative performance with RC. In the shaking table tests, PC frames' maximum acceleration and displacement response were amplified 1.57 - 2.85 and 2.20 - 2.92 times compared to the ground motions. The precast specimens utilizing clamped mechanical splice showed ductile behavior with energy dissipation capacity against strong motion earthquakes.

Response transformation factors and hysteretic energy distribution of reinforced concrete braced frames

  • Herian A. Leyva;Eden Bojorquez;Juan Bojorquez;Alfredo Reyes;Fabrizio Mollaioli;Omar Payan;Leonardo Palemon;Manual A. Barraza
    • Structural Engineering and Mechanics
    • /
    • v.90 no.3
    • /
    • pp.313-323
    • /
    • 2024
  • Most of existing buildings in Mexico City are made of reinforced concrete (RC), however, it has been shown that they are very susceptible to narrow-band long duration ground motions. In recent years, the use of dual systems composed by Buckling Restrained Braces (BRB) has increased due to its high energy dissipation capacity under reversible cyclical loads. Therefore, in this work the behavior of RC buildings with BRB is studied in order to know their performance, specifically, the energy distribution through height and response transformation factors between the RC and simplified systems are estimated. For this propose, seven RC buildings with different heights were designed according to the Mexico City Seismic Design Provisions (MCSDP), in addition, equivalent single degree of freedom (SDOF) systems were obtained. Incremental dynamic analyses on the buildings under 30 narrow-band ground motions in order to compute the relationship between normalized hysteretic energy, maximum inter-story drift and roof displacement demands were performed. The results shown that the entire structural frames participate in energy dissipation and their distribution is independent of the global ductility. The results let propose energy distribution equations through height. Finally, response transformation factors between the SDOF and multi degree of freedom (MDOF) systems were developed aimed to propose a new energy-based approach of BRB reinforced concrete buildings.

Application of 3-D Numerical Wave Tank for Dynamic Analysis of Nonlinear Interaction between Tsunami and Vegetation (쓰나미-식생 비선형 상호작용의 동적해석을 위한 3차원 수치파동수조의 적용)

  • Lee, Woo-Dong;Hur, Dong-Soo
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.36 no.5
    • /
    • pp.831-838
    • /
    • 2016
  • The disaster preventing system using vegetation has been growing in the field of coastal engineering in recent years. To analyze wave and flow fields under nonlinear interactions between tsunami and vegetation, the purpose of this study is to evaluate newly-developed 3-D numerical wave tank including energy dissipation by tsunami-vegetation interaction based on existing N-S solver with porous body model. Comparing numerical results using mean drag coefficient and dynamic drag coefficient due to Reynolds number to existing experimental results it is revealed that computed results considering the dynamic drag coefficient are in good agreement with the laboratory test results for time-domain waveform. In addition, the calculated transmission coefficients of solitary waves in various vegetation densities and incident wave heights are also in good agreement with the experimental values. This confirms the validity and effectiveness of the developed 3-D numerical wave tank with the fluid resistance by vegetation.

Self-timed Current-mode Logic Family having Low-leakage Current for Low-power SoCs (저 전력 SoC를 위한 저 누설전류 특성을 갖는 Self-Timed Current-Mode Logic Family)

  • Song, Jin-Seok;Kong, Jeong-Taek;Kong, Bai-Sun
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.45 no.8
    • /
    • pp.37-43
    • /
    • 2008
  • This paper introduces a high-speed low-power self-timed current-mode logic (STCML) that reduces both dynamic and leakage power dissipation. STCML significantly reduces the leakage portion of the power consumption using a pulse-mode control for shorting the virtual ground node. The proposed logic style also minimizes the dynamic portion of the power consumption due to short-circuit current by employing an enhanced self-timing buffer. Comparison results using a 80-nm CMOS technology show that STCML achieves 26 times reduction on leakage power consumption and 27% reduction on dynamic power consumption as compared to the conventional current-mode logic. They also indicate that up to 59% reduction on leakage power consumption compared to differential cascode voltage switch logic (DCVS).

Nonlinear Dynamic Responses among Wave, Submerged Breakwater and Seabed ($\cdot$수중방파제$\cdot$지반의 비선형 동적응답에 관한 연구)

  • HAN DONG SOO;KIM CHANG HOON;YEOM CYEONG SEON;KIM DO SAM
    • Journal of Ocean Engineering and Technology
    • /
    • v.19 no.6 s.67
    • /
    • pp.35-43
    • /
    • 2005
  • Recently, various-shaped coastal structures have been studied and developed. Among them, the submerged breakwater became generally known as a more effective structure than other structures, bemuse it not only serves its original function, but also has the ability to preserve the coastal environment. Most previous investigations have been focused on the wave deformation and energy dissipation due to submerged breakwater, but less interest was given to their internal properties and dynamic behavior of the seabed foundation under wave loadings. In this study, a direct numerical simulation (DNS) is newly proposed to study the dynamic interaction between a permeable submerged breakwater aver a sand seabed and nonlinear waves, including wave breaking. The accuracy of the model is checked by comparing the numerical solution with the existing experimental data related to wave $\cdot$ permeable submerged breakwater $\cdot$ seabed interaction, and showed fairly nice agreement between them. From the numerical results, based on the newly proposed numerical model, the properties of the wave-induced pore water pressure and the flow in the seabed foundation are studied. In relation to their internal properties, the stability oj the permeable submerged breakwater is discussed.

A Dual Integer Register File Structure for Temperature - Aware Microprocessors (온도 인지 마이크로프로세서를 위한 듀얼 레지스터 파일 구조)

  • Choi, Jin-Hang;Kong, Joon-Ho;Chung, Eui-Young;Chung, Sung-Woo
    • Journal of KIISE:Computer Systems and Theory
    • /
    • v.35 no.12
    • /
    • pp.540-551
    • /
    • 2008
  • Today's microprocessor designs are not free from temperature as well as power consumption. As processor technology scales down, an on-chip circuitry increases power density, which incurs excessive temperature (hotspot) problem. To tackle thermal problems cost-effectively, Dynamic Thermal Management (DTM) has been suggested: DTM techniques have benefits of thermal reliability and cooling cost. However, they require trade-off between thermal control and performance loss. This paper proposes a dual integer register file structure to minimize the performance degradation due to DTM invocations. In on-chip thermal control, the most important functional unit is an integer register file. It is the hotspot unit because of frequent read and write data accesses. The proposed dual integer register file migrates read data accesses by adding an extra register file, thus reduces per-unit dynamic power dissipation. As a result, the proposed structure completely eliminates localized hotspots in the integer register file, resulting in much less performance degradation by average 13.35% (maximum 18%) improvement compared to the conventional DTM architecture.

The Dynamic Nonlinear Analysis of Shell Containment Building subjected to Aircraft Impact Loading (항공기 충돌에 대한 쉘 격납건물의 동적 비선형해석)

  • 이상진
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.15 no.4
    • /
    • pp.567-578
    • /
    • 2002
  • The main purpose of this study is to investigate the dynamic behaviour of containment building in nuclear power plant excited by aircraft impact loading using a lower order 8-node solid element. The yield and failure surfaces for concrete material model is formulated on the basis of Drucker-Prager yield criteria and are assumed to be varied by taking account of the visco-plastic energy dissipation. The standard 8-node solid element has prone to exhibit the element deficiencies and the so-called B bar method proposed by Hughes is therefore adopted in this study. The implicit Newmark method is adopted to ensure the numerical stability during the analysis. Finally, the effect of different levels of cracking strain and several types of aircraft loading are examined on the dynamic behaviour of containment building and the results are quantitatively summarized as a future benchmark.

Design of Low-power Clock Generator Synchronized with the AC Power Source Using the ADCL Buffer for Adiabatic Logics (ADCL 버퍼를 이용한 단열 논리회로용 AC 전원과 동기화된 저전력 클럭 발생기 설계)

  • Cho, Seung-Il;Kim, Seong-Kweon;Harada, Tomochika;Yokoyama, Michio
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.7 no.6
    • /
    • pp.1301-1308
    • /
    • 2012
  • In this paper, the low-power clock generator synchronized with the AC power signal using the adiabatic dynamic CMOS logic (ADCL) buffer is proposed for adiabatic logics. To reduce the power dissipation in conventional CMOS logic and to maintain adiabatic charging and discharging with low power for the ADCL, the clock signal of logic circuits should be synchronized with the AC power source. The clock signal for an adiabatic charging and discharging with the AC power signal was generated with the designed Schmitt trigger circuit and ADCL frequency divider using the ADCL buffer. From the simulation result, the power consumption of the proposed clock generator was estimated with approximately 1.181uW and 37.42uW at output 3kHz and 10MHz respectively.

Implementation of a Simulation Tool for Monitoring Runtime Thermal Behavior (실시간 온도 감시를 위한 시뮬레이션 도구의 구현)

  • Choi, Jin-Hang;Lee, Jong-Sung;Kong, Joon-Ho;Chung, Sung-Woo
    • Journal of the Korea Society of Computer and Information
    • /
    • v.14 no.1
    • /
    • pp.145-151
    • /
    • 2009
  • There are excessively hot units of a microprocessor in today's nano-scale process technology, which are called hotspots. Hotspots' heat dissipation is not perfectly conquered by mechanical cooling techniques such as heatsink, heat spreader, and fans; Hence, an architecture-level temperature simulation of microprocessors is evident experiment so that designers can make reliable chips in high temperature environments. However, conventional thermal simulators cannot be used in temperature evaluation of real machine, since they are too slow, or too coarse-grained to estimate overall system models. This paper proposes methodology of monitoring accurate runtime temperature with Hotspot[4], and introduces its implementation. With this tool, it is available to track runtime thermal behavior of a microprocessor at architecture-level. Therefore, Dynamic Thermal Management such as Dynamic Voltage and Frequency Scaling technique can be verified in the real system.

Artificial intelligence design for dependence of size surface effects on advanced nanoplates through theoretical framework

  • Na Tang;Canlin Zhang;Zh. Yuan;A. Yvaz
    • Steel and Composite Structures
    • /
    • v.52 no.6
    • /
    • pp.621-626
    • /
    • 2024
  • The work researched the application of artificial intelligence to the design and analysis of advanced nanoplates, with a particular emphasis on size and surface effects. Employing an integrated theoretical framework, this study developed a more accurate model of complex nanoplate behavior. The following analysis considers nanoplates embedded in a Pasternak viscoelastic fractional foundation and represents the important step in understanding how nanoscale structures may respond under dynamic loads. Surface effects, significant for nanoscale, are included through the Gurtin-Murdoch theory in order to better describe the influence of surface stresses on the overall behavior of nanoplates. In the present analysis, the modified couple stress theory is utilized to capture the size-dependent behavior of nanoplates, while the Kelvin-Voigt model has been incorporated to realistically simulate the structural damping and energy dissipation. This paper will take a holistic approach in using sinusoidal shear deformation theory for the accurate replication of complex interactions within the nano-structure system. Addressing different aspectsof the dynamic behavior by considering the length scale parameter of the material, this work aims at establishing which one of the factors imposes the most influence on the nanostructure response. Besides, the surface stresses that become increasingly critical in nanoscale dimensions are considered in depth. AI algorithms subsequently improve the prediction of the mechanical response by incorporating other phenomena, including surface energy, material inhomogeneity, and size-dependent properties. In these AI- enhanced solutions, the improvement of precision becomes considerable compared to the classical solution methods and hence offers new insights into the mechanical performance of nanoplates when applied in nanotechnology and materials science.