• Title/Summary/Keyword: hybrid strengthening

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Modeling the confined compressive strength of hybrid circular concrete columns using neural networks

  • Oreta, Andres W.C.;Ongpeng, Jason M.C.
    • Computers and Concrete
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    • v.8 no.5
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    • pp.597-616
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    • 2011
  • With respect to rehabilitation, strengthening and retrofitting of existing and deteriorated columns in buildings and bridges, CFRP sheets have been found effective in enhancing the performance of existing RC columns by wrapping and bonding CFRP sheets externally around the concrete. Concrete columns and piers that are confined by both lateral steel reinforcement and CFRP are sometimes referred to as "hybrid" concrete columns. With the availability of experimental data on concrete columns confined by steel reinforcement and/or CFRP, the study presents modeling using artificial neural networks (ANNs) to predict the compressive strength of hybrid circular RC columns. The prediction of the ultimate confined compressive strength of RC columns is very important especially when this value is used in estimating the capacity of structures. The present ANN model used as parameters for the confining materials the lateral steel ratio (${\rho}_s$) and the FRP volumetric ratio (${\rho}_{FRP}$). The model gave good predictions for three types of confined columns: (a) columns confined with steel reinforcement only, (b) CFRP confined columns, and (c) hybrid columns confined by both steel and CFRP. The model may be used for predicting the compressive strength of existing circular RC columns confined with steel only that will be strengthened or retrofitted using CFRP.

Interfacial stresses in RC beam bonded with a functionally graded material plate

  • Daouadji, Tahar Hassaine;Chedad, Abdebasset;Adim, Belkacem
    • Structural Engineering and Mechanics
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    • v.60 no.4
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    • pp.693-705
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    • 2016
  • Functionally graded material (FGM) plates can be bonded to the soffit of a beam as a means of retrofitting the RC beam. In such plated beams, tensile forces develop in the bonded plate and these have to be transferred to the original beam via interfacial shear and normal stresses. In this paper, an interfacial stress analysis is presented for simply supported concrete beam bonded with a functionally graded material FGM plate. This new solution is intended for application to beams made of all kinds of materials bonded with a thin plate, while all existing solutions have been developed focusing on the strengthening of reinforced concrete beams, which allowed the omission of certain terms. It is shown that both the normal and shear stresses at the interface are influenced by the material and geometry parameters of the composite beam. This research is helpful for the understanding on mechanical behavior of the interface and design of the FGM-RC hybrid structures.

Renovation of steel beams using by imperfect functionally graded materials plate

  • Daouadji, Tahar Hassaine;Abderezak, Rabahi;Rabia, Benferhat;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.41 no.6
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    • pp.851-860
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    • 2021
  • In this paper, a new approach of interface stress analysis in steel beam strengthened by porous FGM (Functionally Graded Materials) is presented to calculate the shear stress in the hybrid steel beam and loaded by a uniformly distributed load. The results show that there exists a high concentration of shear stress at the ends of the imperfect FGM, which might result in premature failure of the strengthening scheme at these locations. A parametric study has been conducted to investigate the sensitivity of interface behavior to parameters such as the rigidity of FGM plate (degree of homogeneity), the porosity index of FGM and the thickness of adhesive all were found to have a marked effect on the magnitude of maximum shear stress in the FGM member. we can conclude that the new approach is general in nature and may be applicable to all kinds of materials.

Manufacturing and Properties of Low Vacuum Plasma Sprayed W-Carbide Hybrid Coating Layer (진공 플라즈마 스프레이 공정을 이용한 W계 복합 코팅층의 제조 및 특성 연구)

  • Cho, Jin-Hyeon;Jin, Young-Min;Ahn, Jee-Hoon;Lee, Kee-Ahn
    • Journal of Powder Materials
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    • v.18 no.3
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    • pp.226-237
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    • 2011
  • W-ZrC and W-HfC composite powders were fabricated by the Plasma Alloying & Spheroidization (PAS) method and the powders were sprayed into hybrid coating layers by using Low Vacuum Plasma Spray (LVPS) process, respectively. Microstructure, mechanical properties, and ablation characteristics of the fabricated coating layers were investigated. The LVPS process led to successful production of W-Carbide hybrid coatings, approximately 400 ${\mu}M$ or above in thickness. As the substrate preheating temperature increased from $870^{\circ}C$ to $917^{\circ}C$, the hardness of the W-ZrC coating layer increased due to decreased porosity. Vickers hardness showed higher value (about 108.4 HV) in W-ZrC hybrid coating material compared to that of W-HfC while adhesive strength was found to be similar in both coating layers. The plasma torch test revealed good ablation resistance of the W-Carbide hybrid coating layers. The relatively high performance W-ZrC coating layer at the elevated temperature is thought to be attributed to both the strengthening effect of ZrC particle remained in the layer and the formation of ZrO2 phase with high temperature stability.

A Study on of Make-up Design with the Application of Genre Deconstruction in Hybrids (Ver. 1) (하이브리드의 탈 장르화를 응용한 메이크업 디자인에 관한 연구(제 1보))

  • Barng, Kee-Jung;Kim, Kyung-Hee
    • The Research Journal of the Costume Culture
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    • v.20 no.3
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    • pp.347-362
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    • 2012
  • Formatively and artistically aspect, a hybrid can be said to be a phenomenon in which two mutually different genres are combined. Make-up is thought to be very important to arrange the foundation available for predicting and pursuing a flow and direction of future hybrid make-up based on this, by analyzing a flow centering on hybrid trend, which was shown previously. In terms of objectives of this study, the first, aim is to suggest a model for researching make-up by grasping the developmental process and the characteristics of hybrid art through considering an art theory of hybridity, shown in make-up. The second, aim is to design make-up by analyzing trends in make-up style after deconstructing the hybrid genre. The modern make-up design through genre-deconstruction characteristics beyond diverse plurality and genre could be known to be highlighted as aesthetic characteristic by a slight attempt as communication of open space, which connects culture and genre, which had failed to be recognized and was neglected. Empirical research has, produced a work by systematically arranging make-up design. This study, identifies two kind of barrier demolition, such as the class deconstruction and the temporal, spatial disorder centering on genre deconstruction of hybrid. There are infinite possibilities in developing make-up design in line with modern sensation through aesthetic element and symbolic significance through genre deconstruction. It was the expression mode in future make-up, to providing basic data, and to strengthening competitive edge of culture and art.

A Study on Make-up Design with Application of Genre Deconstruction in Hybrid(Ver. 2) (하이브리드의 탈 장르화를 응용한 메이크업 디자인에 관한 연구(제 2보))

  • Barng, Kee-Jung;Kim, Kyung-Hee
    • Journal of Fashion Business
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    • v.16 no.2
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    • pp.88-107
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    • 2012
  • Hybrid implies that elements in more than two are combined, and is what is merged and used complexly the technologies and materials in several fields according to the development in scientific technology and the progress in technology. In the formative and artistic aspect, the hybrid can be said to be phenomenon that two of mutually different genres are combined. The function and form in each genre, which were combined at this time, are remained wholly or partially, thereby revealing as well without hiding a fact of having been combined. In the digital communication era, the same time level was integrated into one culture, with destroying the temporal·spatial boundary. As for the objectives of this study, first, the aim is to suggest a model for researching into make-up by grasping the developmental process and the characteristics of hybrid art through considering an art theory of hybrid, which was shown in make-up. Second, the aim is to design make-up by analyzing trend by make-up style after applying the genre deconstruction in hybrid. The modern make-up design through genre-deconstruction characteristics beyond diverse plurality and genre could be known to be highlighted as aesthetic characteristic by a slight attempt as communication of open space, which connects culture and genre, which had failed to be recognized and was neglected. Through the results of this study, it could be known that there is infinite possibility in developing make-up design in line with modern sensation through aesthetic element and symbolic significance through genre deconstruction. Based on these findings, its significance can be said to be in substantially contributing to offering new sight to the design & formative characteristic and the expression mode in future make-up, to providing basic data, and to strengthening competitive edge of culture and art.

Seismic retrofitting and fragility for damaged RC beam-column joints using UHP-HFRC

  • Trishna, Choudhury;Prem P., Bansal
    • Earthquakes and Structures
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    • v.23 no.5
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    • pp.463-472
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    • 2022
  • Reinforced concrete (RC) beam column joints (BCJ) have mostly exhibited poor seismic performance during several past earthquakes, typically due to the poor-quality concrete or lack of reinforcement detailing typical of pre-code design practice. The present study is motivated towards numerical simulation and seismic fragility assessment of one such RC-BCJ. The BCJ is loaded to failure and strengthened using Ultra High Performance-Hybrid Fiber Reinforced Concrete (UHP-HFRC) jacketing. The strengthening is performed for four different BCJ specimens, each representing an intermediate damage state before collapse. viz., slight, moderate, severe, and collapse. From the numerical simulation of all the BCJ specimens, an attempt is made to correlate different modelling and design parameters of the BC joint with respect to the damage states. In addition, seismic fragility analysis of the original as well as the retrofitted damaged BCJ specimens show the relative enhancement achieved in each case.

Interfacial stresses in porous PFGM-RC hybrid beam

  • Benferhat Rabia;Hassaine Daouadji Tahar;Rabahi Abderezak
    • Advances in materials Research
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    • v.13 no.1
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    • pp.37-53
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    • 2024
  • This paper presents a careful theoretical investigation into interfacial stresses in RC beams strengthened with externally bonded imperfect FGM plate. In this study, an original model is presented to predict and to determine the stresses concentration at the imperfect FGM end, with the new theory analysis approach. Stress distributions, depending on an inhomogeneity constant, were calculated and presented in forms. It is shown that both the shear and normal stresses at the interface are influenced by the material and geometry parameters of the composite beam, and it is shown that the inhomogeneities play an important role in the distribution of interfacial stresses. The theoretical predictions are compared with other existing solutions. The numerical resolution was finalized by taking into account the physical and geometric properties of materials that may play an important role in reducing the stress values. This research is helpful for the understanding on mechanical behaviour of the interface and design of the PFGM-RC hybrid structures.

Experimental and numerical investigations into the composite behaviour of steel frames and precast concrete infill panels with window openings

  • Teeuwen, P.A.;Kleinman, C.S.;Snijder, H.H.;Hofmeyer, H.
    • Steel and Composite Structures
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    • v.10 no.1
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    • pp.1-21
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    • 2010
  • As an alternative for conventional structures for tall buildings, a hybrid lateral load resisting structure has been designed, enabling the assembly of tall buildings directly from a truck. It consists of steel frames with discretely connected precast concrete infill panels provided with window openings. Besides the stiffening and strengthening effect of the infill panels on the frame structure, economical benefits may be derived from saving costs on materials and labour, and from reducing construction time. In order to develop design rules for this type of structure, the hybrid infilled frame has recently been subjected to experimental and numerical analyses. Ten full-scale tests were performed on one-storey, one-bay, 3 by 3 m infilled frame structures, having different window opening geometries. Subsequently, the response of the full-scale experiments was simulated with the finite element program DIANA. The finite element simulations were performed taking into account non-linear material characteristics and geometrical non-linearity. The experiments show that discretely connected precast concrete panels provided with a window opening, can significantly improve the performance of steel frames. A comparison between the full-scale experiments and simulations shows that the finite element models enable simulating the elastic and plastic behaviour of the hybrid infilled frame.

A study on resistance & propulsion performance of a 9.77ton hybrid propulsion fishing boat (9.77톤 전기복합 추진어선 저항 추진성능에 관한 연구)

  • Young-Jae Jeong;Yeun-Hee Song;Hye-Young Kang;Kyoung-Wan Lee
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2023.11a
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    • pp.114-115
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    • 2023
  • Research on eco-friendly ships is being actively conducted due to the strengthening of environmental regulations in the shipping sector by the International Maritime Organization (IMO). However, most studies are on large ships, and research on small ships is insufficient. Since most fishermen operate small boats, research on eco-friendly fuel vessels is necessary. This study performed resistance performance analysis, model tests, and POW tests to develop a hybrid electric propulsion ship, and compared and verified the CFD and model test results.

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