• Journal of Welding and Joining
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• 제20권5호
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• pp.93-98
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• 2002

The effect of bonding misfit on single crystallization of transient liquid phase (TLP) bonded joints of single crystal superalloy CMSX-2 was investigated using MBF-80 insert metal. The bonding misfit was defined by (100) twist angle (rotating angle) at bonded interface. TLP bonding of specimens was carried out at 1523K for 1.8ks in vacuum. The post-bond heat treatment consisted of the solution and sequential two step aging treatment was conducted in the Ar atmosphere. The crystallographic orientation analysis across the TLP bonded joints was conducted three dimensionally using the electron back scattering pattern (EBSP) method. EBSP analyses f3r the bonded and post bonded heat treated specimens were conducted. All bonded joints had misorientation centering around the bonded interface for as-bonded and post-bond heat treated specimens with rotating angle. The average misorientation angle between both solid phases in bonded interlayer was almost identical to the rotating angle at bonded interface. HRTEM observation revealed that the atom arrangement of both solid phases in bonded interlayer was quite different across the bonded interface. It followed that grain boundary was formed in bonded interface. It was confirmed that epitaxial growth of the solid phase occurred from the base metal substrates during TLP bonding and single crystallization could not be achieved in joints with rotating angle.

• 한국생산제조학회지
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• 제8권1호
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• pp.35-44
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• 1999

In a view point of earth environmental protection and social requirement, adhesively bonded structures of aluminum alloys have become to be employed for the purpose of decreasing fuel ratio by weight reduction and to improve performance in various engineering fields such as aircrafts, automobiles, rolling stocks and so on. In spite of such wide applications in adhesively bonded structures of aluminum alloys, the quantitative fracture criterion and evolution method of its bonded strength have not been established yet. The objective of this paper is to establish fracture criterion considering stress singularity at interface edges in adhesively bonded structures of aluminum alloys. Through the analyses of boundary element method and static fracture experiments with three different types of specimens in the adhesively bonded joints of aluminum alloys, its fracture criterion was proposed and discussed about strength evolution of adhesively bonded structures.

• Journal of Welding and Joining
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• 제18권4호
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• pp.96-103
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• 2000

This study investigated the effects of bonding temperature and bonding atmosphere on high temperature mechanical properties of transient liquid phase(TLP) bonded joints of heat resistant alloy using MBF-50 insert metal. Specimens were bonded at 1,423~1,468K for 600s. Microconstituents of {TEX}$Cr_{7}(C,B)_{3}${/TEX}were formed in the bonded region when the bonding temperature was low. The amount of microcostituents in the bonded layer decreased with increasing the bonding temperature, and the microconstituents in the bonded layer disappeared at the bonding temperature above 1,468K. The tensile strength of the joints at elevated temperatures increased with the increase the bonding temperature and was the same level as one of the base metal in the bonding temperature over 1,453K. Microstructure and alloying element distributions of the bonded region bonded in Ar and $N_2$atmosphere were similar to those of the bonded in vacuum. The creep rupture strength and rupture lives of joints were almost identical to those of base metal.

• 한국안전학회지
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• 제27권5호
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• pp.141-147
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• 2012

Recently, the external prestressed concrete structures are increasingly being built. The mechanical behavior of prestressed concrete beams with external tendon is different from that of normal bonded PSC beams in that the increment of tendon stress was derived by whole member behavior. By this reason, the ultimate stress of external tendon is smaller than that of bonded tendon or internal unbonded tendon. The purposes of the present paper are therefore to improve the mechanical behavior of external unbonded tendon by using partially bonded external tendon and to evaluate the flexural behavior of partially bonded external tendon by the flexural member experiment. From the experimental results, before flexural cracking, there was no difference between external unbonded, partially bonded and bonded tendons. However, after cracking, yielding load of reinforcement, ultimate load, and tendon stress were increased in the sequence of external unbonded, partially bonded and bonded tendon members. The equation of ACI-318 and AASHTO 1994 were not matched with test results and had no correlations. So the newly proposed equation will be needed including the consideration of tendon profile, tendon bonded type, and so on. The proposed partially bonded external tendon in this paper will be a effective basis for the evaluation of external tendons in construction and design.

• 대한치과보철학회지
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• 제41권1호
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• pp.81-88
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• 2003

Resin-bonded bridge has been an alternative to conventional bridge, since resin-bonded bridge has many attractive advantages such as minimal tooth preparation, short chair time and low cost over conventional bridge. Unfortunately, however, it was reported that resin-bonded bridge showed high failure rate from debonding of retainer in spite of consecutive advances in preparation and materials. And it was shown that multiple abutments were more likely to fail. The majority of debonding failure was considered due to the mobility of the abutment during function. In this view, recently, modification in resin-bonded bridge design was tried. Single retainer, single pontic. 2-unit cantilevered resin-bonded bridge was applied to clinical performance and was shown as retentive or more retentive than fixed-fixed type resin-bonded bridge. This was consistent with the results of studies in 2-unit cantilevered resin-bonded bridges made with all ceramic, In-ceram. The purpose of this article was to overview principles of design and to analyze clinical results of 2-unit cantilevered resin-bonded bridge in comparison with the reports of fixed-fixed resin-bonded bridge.

• 한국도로학회논문집
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• 제15권2호
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• pp.47-55
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• 2013

PURPOSES : This study aimed to evaluate the feasibility of AASHTO86 design method for Bonded Concrete Overlay. METHODS : The Feasibility of AASHTO86 design method for Bonded Concrete Overlay is investigated based on the following study : i) Sensitivity analysis of designed service life of Bonded Concrete Overlay by major design input for AASHTO86 guide. ii) Comparison of actual Bonded Concrete Overlay life and predicted Bonded Concrete Overlay life by AASHTO86. iii) Finding the stress component influence the potential distress of Bonded Concrete Overlay based on 3-d FEM analysis. iv) Exploring the limitation of AASHTO86 in the aspect of design input. RESULTS : Sensitivity analysis showed that the condition of existing pavement significantly on the Bonded Concrete Overlay life. Also the overlay thickness affect the Bonded Concrete Overlay life. The comparison of actual Bonded Concrete Overlay life and predicted Bonded Concrete Overlay life showed relatively good agreement when the early distress sections are excluded in comparison. Bonding stress occurred at the interface may be larger than the bond strength used in the specification of Bonded Concrete Overlay construction. CONCLUSIONS : Bonded Concrete Overlay life predicted by the AASHTO86 may not be reliable. Number of points to improve the reliability in the design of Bonded Concrete Overlay are suggested in this study.

• 한국도로학회논문집
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• 제16권1호
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• pp.1-10
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• 2014

PURPOSES : This study aimed to evaluate the long-term performance of bonded concrete overlay in Korean Highway, and factors influencing the performances. METHODS : The evaluation for long-term performance of bonded concrete overlay is investigated based on the following study : i) The pavement distress of number of bonded concrete overlay sections in Korean highway are collected through field measurement, and PCI for each section is calculated. ii) Performance of LTPP data of bonded concrete overlay sections in U.S.A is analysed. And it is compared with bonded concrete overlay of Korean highway. iii) An analysis of the factors influencing to long-term performance of bonded concrete overlay is investigated. RESULTS : Performance analysis was confirmed that the overlay thickness was affecting significantly on the Bonded Concrete Overlay life. The comparison of LTPP data(U.S.A) and field measurement data(Korean) was showed. CONCLUSIONS : It was showed that the performance of Korean bonded concrete overlay is relatively lower than that of the bonded concrete overlay in U.S.A. The cause of lower performance can be explained by the lack of overlay thickness.

• International Journal of Concrete Structures and Materials
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• 제10권2호
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• pp.149-161
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• 2016

This paper presents an experimental work to study the flexural strength of reinforced concrete (RC) beams strengthened by partially de-bonded near surface-mounted (NSM) fiber reinforced polymer (FRP) strip with various de-bonded length. Especially, considering high anchorage capacity at end of a FRP strip, the effect of de-bonded region at a central part was investigated. In order to check the improvement of strength or deformation capacity when the bonded surface area only increased without changing the FRP area, single and triple lines of FRP were planned. In addition, the flexural strength of the RC member strengthened by a partially de-bonded NSM FRP strip was evaluated by using the existing researchers' strength equation to predict the flexural strength after retrofit. From the study, it was found that where de-bonded region exists in the central part of a flexural member, the deformation capacity of the member is expected to be improved, because FRP strain is not to be concentrated on the center but to be extended uniformly in the de-bonded region. Where NSM FRP strips are distributed in triple lines, a relatively high strength can be exerted due to the increase of bond strength in the anchorage.

• 수산해양교육연구
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• 제28권6호
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• pp.1706-1714
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• 2016

In the 21th century, with the development of the economic global progress, the competition is more stiff. During the fierce competition, 85% of the world's trade volume is root from the sea transportation, that means the harbor trade is becoming an important part in the world's trade. With the strong support of the Chinese national ministries, Tianjin Dongjiang Bonded Port Area had made a series of encouraging results and now becoming a positive mode of the chinese harbor trade port. In the meanwhile, the Dongjiang Bonded Port Area is also searching for the change and a better development. From this year, the Dongjiang Bonded Port Area is apply for the experimental unit to change from the Bonded Port Area to the Free Trade Zone. This paper focus on the Tianjin Dongjiang Bonded Port Area which is the largest port area in the northern part of China. The development progress of the Dongjiang Bonded Port Area is concerned and studied in the paper. This paper expected to research on the transformation progress from the Bonded Port Area to the Free Trade Zone, to find out appropriate ways for the blossom of the harbor trade and the bonded area.

• 수산해양교육연구
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• 제27권6호
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• pp.1832-1841
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• 2015

With the rapid development of global economy and trade, international logistics has made great progress in the past few years. As an irreplaceable part in China's foreign trade industry, ocean shipping, especially. ports management has played a crucial role in the development of China. In 2008, The Qingdao Qianwan bonded port was built in China, and has developed in to a door to connect China to the world. This paper introduced and compared the similarities and differences among the Yangshan Bonded Port, Dalian Dayawan Bonded Port, Tianjin Dongjiang Bonded Port and Qingdao Bonded Port. According to SWOT analysis, a further discussion was then made on the potential problems of Qingdao Bonded Port. At last, some development strategies are given accordingly.