• Title/Summary/Keyword: Impact Study

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Nonlinear finite element analysis of ultra-high performance fiber reinforced concrete beams subjected to impact loads

  • Demirtas, Gamze;Caglar, Naci;Sumer, Yusuf
    • Structural Engineering and Mechanics
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    • v.82 no.1
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    • pp.81-92
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    • 2022
  • Ultra-high performance fiber reinforced concrete (UHPFRC) is a composite building material with high ductility, fatigue resistance, fracture toughness, durability, and energy absorption capacity. The aim of this study is to develop a nonlinear finite element model that can simulate the response of the UHPFRC beam exposed to impact loads. A nonlinear finite element model was developed in ABAQUS to simulate the real response of UHPFRC beams. The numerical results showed that the model was highly successful to capture the experimental results of selected beams from the literature. A parametric study was carried out to investigate the effects of reinforcement ratio and impact velocity on the response of the UHPFRC beam in terms of midpoint displacement, impact load value, and residual load-carrying capacity. In the parametric study, the nonlinear analysis was performed in two steps for 12 different finite element models. In the first step, dynamic analysis was performed to monitor the response of the UHPFRC beam under impact loads. In the second step, static analysis was conducted to determine the residual load-carrying capacity of the beams. The parametric study has shown that the reinforcement ratio and the impact velocity affect maximum and residual displacement value substantially.

Developing and Evaluating Damage Information Classifier of High Impact Weather by Using News Big Data (재해기상 언론기사 빅데이터를 활용한 피해정보 자동 분류기 개발)

  • Su-Ji, Cho;Ki-Kwang Lee
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.46 no.3
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    • pp.7-14
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    • 2023
  • Recently, the importance of impact-based forecasting has increased along with the socio-economic impact of severe weather have emerged. As news articles contain unconstructed information closely related to the people's life, this study developed and evaluated a binary classification algorithm about snowfall damage information by using media articles text mining. We collected news articles during 2009 to 2021 which containing 'heavy snow' in its body context and labelled whether each article correspond to specific damage fields such as car accident. To develop a classifier, we proposed a probability-based classifier based on the ratio of the two conditional probabilities, which is defined as I/O Ratio in this study. During the construction process, we also adopted the n-gram approach to consider contextual meaning of each keyword. The accuracy of the classifier was 75%, supporting the possibility of application of news big data to the impact-based forecasting. We expect the performance of the classifier will be improve in the further research as the various training data is accumulated. The result of this study can be readily expanded by applying the same methodology to other disasters in the future. Furthermore, the result of this study can reduce social and economic damage of high impact weather by supporting the establishment of an integrated meteorological decision support system.

A Study on Floor Impact Sound Insulation Performance of Cross-Laminated Timber (CLT): Focused on Joint Types, Species and Thicknesses

  • Yeon-Su HA;Hyo-Jin LEE;Sang-Joon LEE;Jin-Ae SHIN;Da-Bin SONG
    • Journal of the Korean Wood Science and Technology
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    • v.51 no.5
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    • pp.419-430
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    • 2023
  • In this study, the floor impact sound insulation performance of Korean domestic Cross-Laminated Timber (CLT) slabs was evaluated according to their joint types, species and thicknesses in laboratory experiments. The sound insulation performance of the CLT has not been investigated before, thus, this study was conducted to quantify basic data on floor impact sound insulation performance of CLT slabs. 5-ply and 150 mm thick CLT panels made of 2 species, Larix kaempferi and Pinus densiflora, were used for the study. The CLT panels were assembled by 3 types of inter-panel joints to form floor slabs: spline, butt and half-lap. And the 150 mm thick Larix CLT slabs were stacked to the thicknesses of 300 mm and 450 mm. The heavy-weight floor impact sound insulation performance of the 150 mm CLT slabs were evaluated to be 70 dB for the Larix slabs and 71.6 dB for the Pinus slabs, and the light-weight floor impact sound insulation performance, 78.3 dB and 79.6 dB, respectively. No significant difference in the sound insulation performance was found between the slabs of the 2 species or among the 3 types of joints. The reduction of 1 dB in the heavy-weight floor impact sound and 1.6 dB in the light-weight floor impact sound per 30 mm increase in thickness were confirmed through the experiments. This study can be viewed as the basic research for the evaluation of floor impact sound insulation performance of CLT.

The Effects of Attractiveness of Service Employee's on Interpersonal Trust, Satisfaction and Loyalty (서비스 종업원의 매력성이 대인신뢰와 만족, 애호도에 미치는 영향)

  • KIM, Yu-Kyung
    • The Journal of Industrial Distribution & Business
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    • v.10 no.10
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    • pp.23-34
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    • 2019
  • Purpose - Most past studies related to this focused on the physical attractiveness of service employees, but this study emphasizes the social attractiveness and not just the physical attractiveness of employees. Therefore, the purpose of this study is to first categorize attractiveness as physical attractiveness and social attractiveness and to examine the impact of physical attractiveness on social attractiveness for service industry employees. Secondly, this study aimed at verifying the impact of physical attractiveness and social attractiveness on interpersonal trust. Third, it aimed at revealing the impact of interpersonal trust on customer satisfaction, as well as satisfaction on loyalty. Research design, data, and methodology - Questionnaires were distributed to customers that used beauty salon services, among the various service industries, to verify the hypothesis of this study. Also, hypothesis was analyzed with the structural equation method using Amos 20.0. Results - When presenting the results on verifying the research hypothesis, it was found that physical attractiveness had a positive impact on social attractiveness. Second, while physical attractiveness did not have a positive impact on interpersonal trust, social attractiveness was found to have a positive impact on interpersonal trust. Such results show that in forming interpersonal trust, social attractiveness was more important than physical attractiveness for service industry employees. This result is in contrast with the results of past studies, but it is different in that previous studies suggested only physical attractiveness and did not present social attractiveness in the hypothesis. Third, it was found that interpersonal trust had a positive impact on satisfaction, while satisfaction did not have a positive impact on loyalty. Conclusions - The biggest implication of this study is that it presented social attractiveness, which was rarely dealt with in past studies. Also, this study is significant in that it examined the relationship of physical attractiveness and social attractiveness. The results of this study show that in the service industry, the role of human elements such as service employees is important and that in addition to physical attractiveness, social attractiveness in the course of interaction such as communication with customers can also be an important strategic element.

Macroeconomic and Bank-Specific Variables and the Liquidity of Jordanian Commercial Banks

  • AL-QUDAH, Ali Mustafa
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.12
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    • pp.85-93
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    • 2020
  • This study aimed to explore the impact of macroeconomic (Real GDP growth (GDPG), Inflation rate (INF)) and bank -specific variables (profitability (ROA), capital adequacy (CADEQ), non-performing loans (NPL), deposit growth (DEPG)) on the liquidity (lIQ) of 13 listed Jordanian commercial banks for the period 2011-2018. Panel data analysis, Pooled least square, fixed effects model and random effects model, Lagrange multiplier test, and Hausman test were used. The random effects model output shows that, macroeconomic variables have a significant impact on Jordanian commercial banks liquidity since inflation has a positive impact while GDPG has a negative impact on banks (LIQ). On the other hand among the bank-specific variables capital adequacy and deposit growth have a positive significant impact on banks (LIQ), while (NPL) and (SIZE) have a negative significant impact on Jordanian commercial banks liquidity. But ROA has a negative insignificant impact on (LIQ). The findings of the study suggest that commercial banks departments need to pay attention to the economic and internal variables of banks in order to maintain acceptable levels of liquidity.

Experimental investigation of low-velocity impact characteristics of steel-concrete-steel sandwich beams

  • Sohel, K.M.A.;Richard Liew, J.Y.;Alwis, W.A.M.;Paramasivam, P.
    • Steel and Composite Structures
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    • v.3 no.4
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    • pp.289-306
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    • 2003
  • A series of tests was conducted to study the behaviour of steel-composite sandwich beams under low velocity hard impact. Damage characteristic and performance of sandwich beams with different spacing of shear connector were evaluated under impact loading. Thin steel plates were used as top and bottom skins of the sandwich beams and plain concrete was used as the core material. Shear connectors were provided by welding of angle sections on steel plates. The sandwich beams were impacted at their midpoint by a hemi-spherical nose shaped projectile dropped from various heights. Strains on steel plates were measured to study the effects of impact velocity or impact momentum on the performance of sandwich beams. Spacing of shear connectors is found to have significant effects on the impact response of the beams.

Web Impact Factor and Link Analysis of Indian Council of Agricultural Research (ICAR) Organizations

  • Kumar, Kutty
    • International Journal of Knowledge Content Development & Technology
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    • v.8 no.1
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    • pp.5-23
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    • 2018
  • There have been extensive studies done on webometrics, particularly on the impact of websites and the web impact factor. The present study analyzed the websites of ICAR organizations, according to the webometrics indicator. It examines and explores the 92 ICAR organizational websites in India and identifies a number of web pages and link pages, and calculates the Overall Web Impact Factor (WIF) and Absolute Web Impact Factor (WIF). In this study, all websites were analyzed and data extracted using Google search engine. It suggests that Web Impact Factors can be calculated as a way of comparing the attractiveness of web sites or domains on the Web.

Visual Impact Assessment of the Urban Landscape with Public Participation (주민참여에 의한 도시경관의 영향평가 : 서울시 중계동 아파트 계획안을 대상으로)

  • Oh, Kyushik;Lee, Yongja
    • Journal of Environmental Impact Assessment
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    • v.3 no.1
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    • pp.43-52
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    • 1994
  • This study conducted a visual impact assessment of an apartment complex project proposed in Jungkye-dong, Seoul. Three design alternatives of the project-alternatives 1, 2, and 3-which differed in form, color, scale, and arrangement of buildings were simulated with computer image processing technique. The simulations were presented to the public who were mainly residents in the project area, and visual impact resulted from the alternatives was assessed by them. Their responses were then statistically analyzed. It was found that, in terms of compatibility with the surrounding landscape, alternative 1 was the most favourable because it was more traditional, natural, and diverse than alternatives 2 and 3. At the same time, the alternative was most preferred by the public because it was more plain, natural, and diverse than other alternatives. It was suggested that the visual impact assessment with public participation conducted in this study would help both planners and the public to make more intelligent decisions.

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A Study On the Analysis Of Impact Strain for Hydraulic Breaker Chisel (유압식 착암기 치즐의 타격 변형량 해석에 관한 연구)

  • Park, J.W.;Lee, K.W.;Kim, H.E.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.4 no.4
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    • pp.21-27
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    • 2007
  • A hydraulic breaker for construction machinery generally used for the destroying and disassembling of buildings, crashing road pavement, breaking rocks at quarry and so on. So the measurement of the impact energy of a hydraulic breaker is very important thing to prove its capability to manufacturers and customers. Therefore the prediction of impact energy in design process is very helpful to the most of breaker manufacturers. In this study, we carried on modeling and simulation of a hydraulic breaker to predict impact energy via commercial CAE software. The modeling and simulation of a hydraulic breaker was achieved with two parts. One is a hydraulic circuit analysis part via AMESim and the other is impact strain analysis part via ANSYS.

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Impact Responses of Two Colliding Bodies Considering Sensor Dynamics (센서 동역학을 고려한 충돌체간의 충격응답)

  • 류봉조;안길영;권병희;송오섭;이종원
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.5
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    • pp.394-401
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    • 2004
  • This paper presents a study on the analysis of impact responses taking into account sensor dynamics. The contact force between impacting bodies is modelled by using Hertz force-displacement law and linear damping function. Since the real impact force and acceleration at the contact surface of two colliding bodies are measured indirectly by the sensors, the measured outputs can be a little different from the real impact responses. Therefore, in this study, the importance of consideration of sensor dynamics in the impact problems of two colliding bodies is emphasized. In order to verify the appropriateness of the proposed contact force model, the drop type impact test using two kinds of sensors is carried out. Through the numerical analysis and experiment, the effect of sensor dynamics and characteristics on the contact force model is investigated.