• The Journal of Korean Academy of Prosthodontics
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• v.41 no.1
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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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.372-380
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• 2003

Impact tests were conducted to study the effect of angle ply and metal laminate on impact damage characteristics of Fiber Metal laminates (FML). Impact tests were conducted using drop weight impact machine and damage behavior were analyzed by comparing with load-displacement curve and surface observation and microscopic observation of cross sections. The effect of angle ply on impact characteristics of FML are influenced by property of metal laminate. i.e., when the metal laminate is not enough to strong to prevent fiber debonding, Angle ply FML is superior to singly oriented ply (SOP) FML because angle ply enhance the stiffness by fiber supports and prevent (rack propagation. However, when the metal laminate is enough to strong to prevent fiber debonding, SOP FML is superior to Angle ply FML because the fiber of lower ply in Angle ply FML are more stressed than that of SOP FML.

• Journal of Korean Society of Steel Construction
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• v.26 no.2
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• pp.69-79
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• 2014

This paper presents the experimental results of flexural behavior of steel beam strengthened with fiber reinforced polymer plastic (FRP) strips subjected to static bending loading. Four H beams were fabricated strengthened with aramid strips and carbon strips and one control specimen were also fabricated. Among them two specimens were strengthened with partial length. The H-beams had two types of failure mode, depending on the length of the FRP strips:(1) strip debonding in beams with partial length reinforcement and (2) strip rupture in beams with full length reinforcement. From the test, it was observed that maximum increase of 16% was also achieved in bending-load capacity.

• Journal of Technologic Dentistry
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• v.22 no.1
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• pp.39-47
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• 2000

This study is the know the difference bond strength according to painting method of Opaque porcelain. Among Porcelain powder for Porcelain, Noritake powder, Bonding agent 1 class and metal are selected as Base metal alloy. And painting method of Opaque porcelain is divided by 4 groups : PG, WG, NG and DG. Also it is to manufacture 24 sheets of Specimen by 6 each every method and to measure Crack-initiation Strength of Metal-porcelain and it is to observe it by Scanning electron microscope. I come to get a conclusion as follows. 1. As for Debonding strength of every experiment groups, it showed that WS group which executed Wash bake had highest value, 44.25MPa and NG group which used Normal powder had value, 42.11MPa and DG group which used Bonding agent had value, 35.88MPa and PG group which used Paste opaque had value, 35.39MPa. 2. In four painting methods of Opaque porcelain, PG group, WG group, NG group and DG group, there is no significant difference statistically in Crack-initiation Strength. 3. As a result of observing fracture surface with Scanning electron microscope, it was showde that PG group remained a lot of particle of porcelain on the surface of metal than WG group, NG group and DG group.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.2
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• pp.1-6
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• 2011

This study aims at predicting structural behaviors of RC (Reinforced Concrete) beams retrofitted with hybrid FRPs (Fiber Reinforced Polymers). Toward this goal, structural analysis for the RC beams retrofitted with hybrid FRPs are performed and validated using existing experimental data. For the analysis, failure models due to debonding of FRPs and concrete separation are implemented within FE (Finite Element) model, based on Smith and Teng, model, and Teng and Yao model, respectively. Nonlinear material and geometrical effects are also included in the analysis. The suggested modeling approaches are able to predict structural behaviors of RC beams retrofitted with hybrid FRPs similar to the experimental data, however, a numerical model needs to be developed in order to predict failure strength of RC beams retrofitted with hybrid FRPs accurately.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.737-742
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• 1994

The fracture energy of glass fiber/carbon fiber/epoxy resin hybrid composite system was investigated in the aspect of fracture mechanism. Epoxy resin matrix was DGEBA-MDA-SN-HQ system. On the interface of glass fiber and matrix, post debone friction energy provided a major contribution to the fracture energy, and debonding energy and pull-out energy were of the similar value. In the case of fracture on the interface of carbon fiber and matrix, pull-out energy was the major contributor.

• Journal of Adhesion and Interface
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• v.5 no.4
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• pp.9-16
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• 2004

Silk fibers were subjected to argon and ethylene plasma treatments in order to improve the interfacial adhesion with polylactic acid (PLA). After the plasma surface treatment, the surface morphology and surface adhesion of silk fibers to the PLA resin were largely changed. Various plasma treatment conditions were used in this work: 10, 25, 50, 100 and 150 W of electric power, 1, 3, 5, 7 and 10 minutes of treatment time, and 10 and 50 sccm of a gas flow rate. The interfacial shear strength of plasma-treated Silk/PLA biocomposites was measured by a single fiber micro-droplet debonding test method. The result provided an optimal plasma treatment condition to obtain the improved interfacial adhesion in the Silk/PLA biocomposites.

• Structural Engineering and Mechanics
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• v.44 no.6
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• pp.705-733
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• 2012

In this work, an experimental examination was carried out to study interfacial stresses developed at the junction zones between carbon fiber reinforced plastic (CFRP) fabrics (~1 mm thickness) and tensile concrete portion in CFRP retrofitted RC beams. In this respect, initially six similar RC beams of $150{\times}150{\times}1000mm$ dimensions were prepared. Three of which were strengthened with CFRP fabrics at the tensile side of the beams. Furthermore, a notch was cut at the center of the bottom surface for all of the studied beams. The notch was 15 mm deep and ran across the full width of tension side of the beams. The mentioned interfacial stresses could be calculated from strains measured using strain gauges mounted on the interface zone of the tensile concrete and the CFRP sheet. Based on the results obtained, it is shown that interfacial stresses developed between CFRP fabrics and RC beam had a noticeable effect on debonding failure mode of the latter. The load carrying capacity of CFRP strengthened RC specimens increased ~75% compared to that of the control RC beams. This was attributed to the enhancement of flexural mode of the former. Finally, finite element analysis was also utilized to verify the measured experimental results.

• Korean Journal of Materials Research
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• v.3 no.2
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• pp.140-144
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• 1993

Abstract To modify brittleness among the properties of thermosetting epoxy resin, a reactive additive. succinonitrile(SN) was introduced to Diglycidyl ether of bisphenol A(DGEBA)-4, 4'-methylene dianiline (MDA) system. Fracture behavior was microscopically studied during breaking of composite materials. As a result, post debond friction energy was the most significant for breaking the composite having glass fibres, pull-out energy was the next significant and debonding energy was the last. It was observed that shear stress between glass fibre and epoxy matrix was main factor for fracture behavior. Reactive additive, SN made shear stress deteriorated.

• Steel and Composite Structures
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• v.22 no.6
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• pp.1337-1358
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• 2016

The current study focuses on the assessment and interface response of reinforced concrete elements with composite materials (carbon fiber reinforced polymers-CFRPs, glass fiber reinforced polymers-GFRPs, textile reinforced mortars-TRM's, near surface mounted bars-NSMs). A description of the transfer mechanisms from concrete elements to the strengthening materials is conducted through analytical models based on failure modes: plate end interfacial debonding and intermediate flexural crack induced interfacial debonding. A database of 55 in total reinforced concrete columns (scale 1:1) is assembled containing elements rehabilitated with various techniques (29 wrapped with CFRP's, 5 wrapped with GFRP's, 4 containing NSM and 4 strengthened with TRM). The failure modes are discussed together with the performance level of each technique as well as the efficiency level in terms of ductility and bearing/ bending capacity. The analytical models' results are in acceptable agreement with the experimental data and can predict the failure modes. Despite the heterogeneity of the elements contained in the aforementioned database the results are of high interest and point out the need to incorporate the analytical expressions in design codes in order to predict the failure mechanisms and the limit states of bearing capacities of each technique.