Impact resistance of fiber-reinforced concrete – A review

Yoo, Doo-Yeol,Banthia, Nemkumar Elsevier 2019 CEMENT AND CONCRETE COMPOSITES Vol.104 No.-

<P><B>Abstract</B></P> <P>This paper reviews the state of the art of the impact resistance of ordinary fiber-reinforced concretes (FRCs) containing various fibers. First, various types of impact test methods that are current available are addressed as well as some concerns about them based on extensive literature reviews and our perspective. Then, common properties of FRCs under impact loading regardless of fiber type, such as the reasons for their enhanced strength under impact, the effect of size on impact resistance, and several factors (i.e., matrix strength, loading conditions, and fiber existence) that influence strain-rate sensitivity, are discussed. Furthermore, the comprehensive impact resistances of FRCs with various fibers (i.e., steel, polymeric, carbon, basalt, natural, and hybrid fibers) are investigated under different loading conditions. After summarizing the impact properties of FRCs with various fibers, the comparative impact resistance of FRCs according to the fiber type is evaluated to determine which type gives the best improvement of impact resistance. Lastly, the effect of supplementary cementitious materials (SCMs), i.e., fly ash, silica fume, and slag, on the impact resistance of FRCs is examined, and some combinations of SCM and fiber types that lead to enhanced impact resistance are suggested.</P>

The effects of stacking sequence on the penetration-resistant behaviors of T800 carbon fiber composite plates under low-velocity impact loading

Furqan Ahmad,Jung-Wuk Hong,Heung Soap Choi,Soo-Jin Park,Myung Kyun Park 한국탄소학회 2015 Carbon Letters Vol.16 No.2

Impact damages induced by a low-velocity impact load on carbon fiber reinforced polymer (CFRP) composite plates fabricated with various stacking sequences were studied experimentally. The impact responses of the CFRP composite plates were significantly affected by the laminate stacking sequences. Three types of specimens, specifically quasi-isotropic, unidirectional, and cross-ply, were tested by a constant impact carrying the same impact energy level. An impact load of 3.44 kg, corresponding to 23.62 J, was applied to the center of each plate supported at the boundaries. The unidirectional composite plate showed the worst impact resistance and broke completely into two parts; this was followed by the quasi-isotropic lay-up plate that was perforated by the impact. The cross-ply composite plate exhibited the best resistance to the low-velocity impact load; in this case, the impactor bounced back. Impact parameters such as the peak impact force and absorbed energy were evaluated and compared for the impact resistant characterization of the composites made by different stacking sequences.

Impact-resistant design of RC slabs in nuclear power plant buildings

Li Z.C.,Jia P.C.,Jia J.Y.,Wu H.,Ma L.L. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.10

The concrete structures related to nuclear safety are threatened by accidental impact loadings, mainly including the low-velocity drop-weight impact (e.g., spent fuel cask and assembly, etc. with the velocity less than 20 m/s) and high-speed projectile impact (e.g., steel pipe, valve, turbine bucket, etc. with the velocity higher than 20 m/s), while the existing studies are still limited in the impact resistant design of nuclear power plant (NPP), especially the primary RC slab. This paper aims to propose the numerical simulation and theoretical approaches to assist the impact-resistant design of RC slab in NPP. Firstly, the continuous surface cap (CSC) model parameters for concrete with the compressive strength of 20 e70 MPa are fully calibrated and verified, and the refined numerical simulation approach is proposed. Secondly, the two-degree freedom (TDOF) model with considering the mutual effect of flexural and shear resistance of RC slab are developed. Furthermore, based on the low-velocity drop hammer tests and high-speed soft/hard projectile impact tests on RC slabs, the adopted numerical simulation and TDOF model approaches are fully validated by the flexural and punching shear damage, deflection, and impact force time-histories of RC slabs. Finally, as for the two low-velocity impact scenarios, the design procedure of RC slab based on TDOF model is validated and recommended. Meanwhile, as for the four actual high-speed impact scenarios, the impact-resistant design specification in Chinese code NB/T 20012-2019 is evaluated, the over conservation of which is found, and the proposed numerical approach is recommended. The present work could beneficially guide the impact-resistant design and safety assessment of NPPs against the accidental impact loadings.

Impact Resistance and Comfort Properties of Textile Structures for Sportswear

Rajkishore Nayak,Sinnappoo Kanessalingam,Arun Vijayan,Lijing Wang,Rajive Padhye,Lyndon Arnold 한국섬유공학회 2020 Fibers and polymers Vol.21 No.9

Protective padding is commonly used in many sporting activities to prevent impact related injuries. In rugby,shoulder pads absorb and disperse the force and energy of an impact with a playing surface or another player. Although themajority of the commercial shoulder pads currently available can reduce the impact force during a front-on tackle, theyprovide limited amount of thermal comfort to the wearer. In this research, flexible textile structures were designed andinvestigated for their potential to effectively dissipate the force of impact over a wider area, thus reducing the risk of injury. The impact resistance of these textile structures placed over a body simulant was compared against commercial foam padsusing a ‘drop test’ method. The results indicated that all the flexible textile structures reduced the impact force. Although theirprotection level was not as high as the commercial foam, the textile structures showed a higher level of thermal comfort asmeasured by air permeability, thermal resistance and water vapor resistance. The results were analyzed using onewayANOVA followed by post-hoc analysis using IBM SPSS software. The Post-hoc analysis showed a significant differenceamong the test results of various fabrics for impact absorption, air permeability, thermal resistance and water vaporresistance, which are also discussed in this paper.

혁신저항 극복을 통한 스마트 팩토리 관련 기술의 수용의도 제고 방안에 관한 연구

이윤호 ( Yoon Ho Lee ),박찬권 ( Chan Kwon Park ) 한국로지스틱스학회 2021 로지스틱스연구 Vol.29 No.6

The purpose of this study is to analyze the reasons for the low level of smart factory introduction and utilization by small and medium-sized manufacturing companies in Korea. For this, network effect, social impact, organizational characteristics, and technological readiness were selected as the leading factors for resistance to the introduction of smart factory-related technology, that is, innovation resistance. Study the impact. Furthermore, it analyzes differences according to supply chain characteristics, company size, and level of technological readiness. Data from 131 small and medium-sized manufacturing enterprises were collected, reliability and validity analysis were performed, and research hypotheses were tested using research items that met all of them. As a result of testing the research hypothesis, the network effect had a negative (-) effect on innovation resistance, but was not significant. Social influence has a significant negative (-) effect on innovation resistance. Organizational characteristics have a significant negative (-) effect on innovation resistance. Technology readiness has a significant negative (-) effect on innovation resistance. Finally, innovation resistance was tested to have a significant negative (-) effect on the intention to accept technology. And in the analysis of differences according to supply chain characteristics, in innovation resistance, in the analysis of differences according to company size, in organizational characteristics, technology readiness, innovation resistance, in the analysis of differences according to the level of technology readiness, organizational characteristics, technology readiness, and technology acceptance There is a significant difference in intent. In order to reduce innovation resistance through these research results, it is necessary to raise the level of social impact, organizational characteristics, and technological readiness. In addition, smart factory-related technologies should be introduced from industries that constitute a reactive supply chain, relatively large companies, and companies with a high level of technological readiness.

Numerical Analysis of the Impact Resistance of Partially Precast Concrete Beams and Prediction of the Displacement Response

Huimin Mao,Xueyuan Yan,Chenchen Zong,Cihang Lin 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5

A building can be subject to multiple accidental loads during its service life. Partially precast concrete (PC) beams are primary force-bearing members. When subjected to an impact load, their impact resistance considerably affects the overall safety of the structure. In this study, we performed numerical analyses of the dynamic response of PC beams subjected to impact loading. The related parameters, including the element type, material model, contact type, and hourglass control, were discussed in detail. The simulation and test results were compared. The model's validity is verified from four aspects: energy conversion, failure form, impact-force time history curve, and midspan-displacement time history curve. Based on these findings, the effects of the concrete strength, longitudinal reinforcement ratio, and stirrup ratio on the impact resistance of the components were evaluated. Furthermore, the differences in the equivalent plastic strain cloud diagram, impact-force time history curve, and midspan-displacement time history curve under different parameters were compared. The results show that an increase in the strength of the post-pouring concrete can reduce local damage to PC beams, and improving the overall strength of concrete can reduce overall damage of PC beams. In addition, an increase in the longitudinal reinforcement ratio can ease the failure of the normal cross-section of PC beams, and an increase in the stirrup ratio can effectively inhibit the generation and development of oblique cracks. Then, by fitting the parameters, we established simplified formulas for calculating the peak and residual values of the midspan displacement. According to the formulas, when the external impact mass and height are known, the component's damage degree can then be predicted, which provides a basis for the design of fabricated structures.

Aerodynamic Resistance Induces Different Temperature Responses to Earlier Green-up and Delayed Dormancy

Chang-Eui Park,Sujong Jeong 한국기상학회 2021 한국기상학회 학술대회 논문집 Vol.2021 No.10

The growing season of temperate and boreal forests is lengthening as increasing global mean temperature. Examining the impact of growing season change on climate needs accurate estimation of surface temperature response to phenological changes in vegetation in spring and autumn. Here, biogeophysical sensitivity of surface temperature to earlier green-up in spring and delayed dormancy in autumn is investigated over the seasonal deciduous forests in the Northern Hemisphere by applying two resistance mechanism (TRM) method to experiments using Community land model version 5 (CLM5). Results show that both earlier leaf onset and delayed leaf senescence induce surface cooling according to the decrease in surface resistance, which increases surface latent heat release. However the cooling impact of earlier green-up is larger than that of delayed dormancy even for same change in date of leaf onset and leaf senescence. This asymmetric impact between same phenological change in spring and autumn is explained by different temperature sensitivity to aerodynamic resistance. The decrease in surface temperature according to reduced aerodynamic resistance is notable for earlier leaf onset, which strengthens the surface cooling in spring. In contrast, the delay in leaf senescence leads to slight impact of aerodynamic resistance on surface temperature. Results suggest that different response of surface temperature to aerodynamic resistance in spring and autumn season is one of keys to explain the asymmetric impact of earlier green-up and delayed dormancy on spring and autumn climate.

비산물에 대한 지붕 강판의 내충격 성능 평가

유장열,정다와,유기표 대한건축학회 2024 대한건축학회논문집 Vol.40 No.1

연구의 목적은 비산물에 대한 지붕 강판과 같은 외장재의 내충격 성능을 평가하는 것이다. 미국·일본과 같이 허리케인, 태풍에 빈번히 노출되는 국가에서는 이미 비산물에 대한 외장재 내충격 시험을 실시하고 있다. 우리나라 또한 태풍 및 강풍에 의한 외장재 파손 피해가 많이 발생하고 있다. 따라서 비산물에 의한 내충격 시험이 필요하다고 생각한다. 본 연구에서는 해외 기준을 참고하여 내충격 시험 장치를 개발하고 시험 방법을 확립하였다. 또한 지붕강판에 대한 내충격 시험을 실시하여 그 결과를 나타냈다. 시험 결과, 시험체 관통이 일어나는 최소 임계치는 0.35mm 두께의 강판에 D Type 이상의 가격체를 발사하였을 경우이다. 그리고 지붕 강판의 겹침 부위에서는 1.5골 겹침에 가격체 E Type을 발사하였을 때 관통이 발생했다. 이 때 사용된 볼트 간격을 200mm에서 100mm로 변경하여 가격체 E Type으로 시험해본 결과 관통이 발생하지 않았다. This research aims to assess the impact-resistant performance of cladding materials, such as roof steel sheets, against windborne debris. Countries like the United States and Japan, prone to hurricanes and typhoons, routinely conduct impact tests on exterior materials. Korea,facing damage from typhoons and strong winds, also requires evaluating impact resistance through missile tests. This study develops testequipment based on international standards, establishes a test method, and conducts impact resistance tests on roof steel plates. Followingthese tests, penetration occurred when a missile of type D or higher struck the non-overlapping 0.35mm thick steel plate. At overlappingpoints, an impact with a missile of type E was applied to the 1.5 furrow part. In earlier findings, adjusting bolt spacing from 200mm to100mm at overlapping points prevented penetration, even during a missile impact of type E.

Influences of weaving architectures and impact locations on the ballistic resistance of UHMWPE fabric

Zihan Zhu,Hu Zhou,Xiangshao Kong,Fang Liu,Yongqiang Zhang,Cheng Zheng,Weiguo Wu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

This study is devoted to reveal the influence of weaving architectures and impact locations on the ballistic resistance of UHMWPE (ultrahigh high molecular weight polyethylene) fabrics. Firstly, a mesoscopic model of UHMWPE fabric is established and the accuracy of the numerical method is verified. Subsequently, the models with different weaving architectures are further established, and the impact resistance performances are evaluated. Finally, the influence factors on the fabric ballistic resistance is explored. It is proved that the ballistic resistance of UHMWPE fabric mainly dominated by the tensile strength of yarn under highvelocity impact. The plain fabric shows best anti-ballistic performance, while basket and woven fabric are slightly inferior. The damage pattern of fabrics with different weaving architectures changes greatly. In addition, this study proposes a residual impact velocity correction model for projectile based on the probability distribution of impact positions, which can better characterize the protective ability of fiber fabrics.

기둥 보강용 PROTECT 방폭 패널의 충격저항성능

손성곤(Son, Seong-Gon),박민재(Park, Min-Jae),류재호(Ryu, Jae-Ho),주영규(Ju, Young k.) 대한건축학회 2017 大韓建築學會論文集 : 構造系 Vol.33 No.2

As the threat of terrorist attacks or explosive accidents increases, interest in design and construction of blast resistant structures has increased. Recently, the blast reinforcement for existing buildings which were not designed to resist blast loading has been issued, and the demands for blast protective materials are continually growing. This study investigates the analytical study for evaluating impact resistance capacity and failure mode of PROTECT (Poly Resilience-Oriented hybrid TEChnology plaTe) panel. PROTECT panel is a composite panel with two steel plates and nano-composite. Since it is a multi-layer structure, there are advantages for the blast resistance. The impact resistance analysis of PROTECT panel is performed with the impact energy, the thickness of the steel plates and nano-composite as variables. In order to perform impact analysis, dynamic properties of steels and nano-composite were determined. Finite element analysis is performed with these properties under the drop-weight impact. From the finite element analysis, different failure modes corresponding to different impact energy is derived.