• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.835-845
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• 1994

In this paper, the effects of the adhesive thickness and adherend roughness on the static and fatigue strengths of the adhesively bonded circular single lap joints has been investigated by an experimental method. The stacking sequence effect of the composite adherend on the static and fatigue strength and the fracture patterns of the adhesive failure were also observed. Since the circular single lap joint fails catastrophically beyond the static strength of fatigue limit, the tubular polygonal adhesively bonded joints such as triangular, tetragonal, pentagonal, hexagonal as well as elliptical joints were manufactured in order to give partial mechanical characteristics to the adhesively bonded tubular joints. These joints were tested both in static and fatigue modes. From the experimental investigations, it was found that the fatigue strength of the circular adhesively bonded joints was much dependent on the arithmetical average surface roughness of the adherends and the polygonal adhesively bonded joints had better fatigue strength characteristics than the circular adhesively bonded joints.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.29-37
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• 1998

Alkali-soluble extracts were prepared from medium-sized barks of Radiata pine(Pinus radiata). There are difficulties in the production of extracts with uniform quality and in the preparation of adhesives with suitable viscosity. Ultrafiltration using an Amicon cell was subjected to fractionate extracts according to molecular sizes in order to overcome the above problem. The filtration efficiency was studied by using thin channel filtration systems. Adhesive manufacturing was also examined. Removal of particles greater than 0.45m from the extracts increased both filtration speed (flux) and yields of solids in the filtrates. Ultrafiltration with PM 10 membrane was very effective to fractionate and concentrate the extracts. Stiasny precipitates from the filtrates obtained by PM 10 membrane were very lower than that(83%) of the retentates. This ultrafiltration method was efficient for obtaining high yield purified phenolic compounds(mainly polyflavanoids) and thus important for preparing wood adhesives from barks. The extracts were shown excessive high viscosities at the concentrations required for adhesive formulation, but this high viscosity and short gelation time was reduced by lowering pH of the extracts and addition of urea. The highest bonding strength of plywoods(340g/$m^2$ of adhesive spreads) was achieved with adhesive formulated by 100parts of mixed alkali extracts and urea(70/30,w/w), 10parts of p-formaldehyde and 3.5parts of wheat flour at pH 6, and by hot pressing at the conditions of 12kg/$cm^2$ at $120^{\circ}C$ for 10 minutes.

• Journal of Adhesion and Interface
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• v.21 no.1
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• pp.20-26
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• 2020

Single lap-shear joints (SLJ) specimens with and without partial round fillets were fabricated to measure the average shear strength of adhesives. The effects of the length of the adherend on the SLJ specimens were also investigated. An epoxy adhesive was used to bond aluminum alloy. Tensile tests were performed on the adhesive bulk specimens to measure the mechanical properties. The finite element analysis (FEA) method was used to measure the adhesive stress distributions, i.e., the peel and shear stresses, on the bonded part. The experimental results revealed that the specimen consisting short length of adherend and without the partial round fillets exhibited the smallest average shear strength of adhesive among the investigated specimens. FEA revealed that the low average shear strength for the specimen with a short adherend length was caused by high stress concentrations on the adhesive at the edge of the bonded part.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.230-237
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• 2003

Ultrasonic testing method has been developed to evaluate adhesive layers in blast tube for the reliability of the rocket. The main objective of the present work was to find debonding and missing adhesive in epoxy layer between steel and FRP layers. In this approach, the ultrasonic reflection from the interface between the steel sheet and the epoxy adhesive is measured with a high-frequency pulse-echo setup in order to identify contact debonding and missing adhesive. Then, the steel sheet is excited to resonance by low-frequency ultrasound, and the gap size underneath the measuring location is estimated from the resonance responses. For practical application in industry an automated testing system has been developed where the proposed approach is implemented. The performance of the proposed approach has been verified by actual measurement of gap sizes from the cross-sections of cut specimens using an optical microscope.

• The Journal of Advanced Prosthodontics
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• v.13 no.5
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• pp.292-303
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• 2021

PURPOSE. The aim of this in vitro study was to evaluate the effect of silane and universal adhesive applications on the micro-shear bond strength (µSBS) of different resin-matrix ceramics (RMCs). MATERIALS AND METHODS. A total of 120 slides (14 × 12 × 1 mm) were produced from 5 different RMC materials (GC Cerasmart [GC]; Brilliant Crios [BC]; Grandio blocs [GB]; Katana Avencia [KA]; and KZR-CAD HR 2 [KZR]) and sandblasted using 50 ㎛ Al₂O₃ particles. Each RMC material was divided into six groups according to the surface conditioning (SC) method as follows: control (G1), silane primer (G2), silane-free universal adhesive (G3), silane-containing universal adhesive (G4), silane primer and silane-free universal adhesive (G5), and silane primer and silane-containing universal adhesive (G6). Three cylindric specimens made from resin cement (Bifix QM) were polymerized over the treated surface of each slide (n = 12). After thermal cycling (10000 cycles, 5 - 55℃), µSBS test was performed and failure types were evaluated using a stereomicroscope. Data were analyzed using 2-way ANOVA and Tukey tests (α = .05). RESULTS. µSBS values of specimens were significantly affected by the RMC type and SC protocols (P < .001) except the interaction (P = .119). Except for G2, all SC protocols showed a significant increase in µSBS values (P < .05). For all RMCs, the highest µSBS values were obtained in G4 and G6 groups. CONCLUSION. Only silane application did not affect the µSBS values regardless of the RMC type. Moreover, the application of a separate silane in addition to the universal adhesives did not improve the µSBS values. Silane-containing universal adhesive was found to be the best conditioning method for RMCs.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.624-631
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• 2019

The purpose of this study was to observe the influence of adhesive force of lifter on powdered fingermark. First, an experiment was conducted to measure the adhesive force of five kinds of lifters. Second, each fingermark deposited on slide glass was developed using four kinds of powders. Then, these were transferred to lifter, and the quality of the transferred fingermark was observed. As a result of measuring the adhesive force of the lifter using the ASTM D3121-17 rolling ball tack method, the difference in adhesion between the lifters except the gelatin lifter was small. Also, it was confirmed that the quality of the transferred fingermark was not significantly related to the adhesive force of the lifter. However, if the quality of the transferred fingermark is not good when transferring to a gelatin lifter which is a lifter having a weak adhesive force, additional transfer is possible.

• Composites Research
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• v.13 no.4
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• pp.42-53
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• 2000

A study has been made to establish an optimum condition in the surface treatment and curing method that is important for the fabrication of Al 7075/CFRP laminates. PAA(Phosphoric Acid Anodizing) provided a good adhesive strength and FPL(Sulfuric / Sodium Dichromate Acid Etching) had a similar adhesive strength with PAA. On the other hand, the poor adhesive strength was shown on vapor degrease and CAA(Chromic Acid Anodizing). By using the atomic force microscope(AFM), it was found that the PAA oxide surface obviously had a greater degree of microroughness as compared to vapor degrease, CAA and FPL treated surfaces. These results support the concept of a mechanical interlocking of the adhesive with-in the oxide pores as the predominant adhesion mechanism. In curing methods, the adhesive strength of co-curing method was higher than that of secondary curing method. With respect to stability of specimen shape, the secondary curing method was better than co-curing method. DMA(Dynamic Mechanical Analysis) test revealed $T_g$ in curing times over 60 min is nearly same, so it is estimated they will have similar degree of curing and joint durability in using FM300M adhesive film.

• Journal of the Semiconductor & Display Technology
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• v.5 no.2 s.15
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• pp.33-36
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• 2006

Many issues arose to use the Pb-free solder as adhesive materials in MEMS ICs and packaging. Then this study for easy and simple sealing method using adhesive materials was carried out to maintain hermetic characteristic in MEMS Package. In this study, Hermetic characteristic using negative PR (XP SU-8 3050 NO-2) as adhesive at the interface of Si test coupon/glass substrate and Si test coupon/LTCC substrate was examined. For experiment, the dispenser pressure was 4 MPa and the $200\;{\mu}m{\Phi}$ syringe nozzle was used. 3.0 mm/sec as speed of dispensing and 0.13 mm as the gap between Si test coupon and nozzle was selected to machine condition. 1 min at $65^{\circ}C$ and 15 min at $95^{\circ}C$ as Soft bake, $200\;mj/cm^2$ expose in 365 nm wavelength as UV expose, 1 min at $65^{\circ}C$ and 6 min at $95^{\circ}C$ as Post expose bake, 60 min at $150^{\circ}C$ as hard bake were selected to activation condition of negative PR. Hermetic sealing was achieved at the Si test coupon/ glass substrate and Si test coupon/LTCC substrate. The leak rate of Si test coupon/glass substrate was $5.9{\times}10^{-8}mbar-l/sec$, and there was no effect by adhesive method. The leak rate of Si test coupon/LTCC substrate was $4.9{\times}10^{-8}mbar-l/sec$, and there was no effect by dispensing cycle. Better leak rate value could be achieved to use modified substrate which prevent PR flow, to increase UV expose energy and to use system that controls gap automatically with vision.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.913-914
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• 2010

• Journal of Korean Dental Science
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• v.2 no.2
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• pp.5-11
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• 2009

Objectives : This study investigated the hypothesis that the dentin bond strength of self-etching adhesives (SEAs) may be improved by applying a coat of hydrophobic, neutral adhesive resin in addition to SEA. Method and Materials : The bond strengths of two SEAs - Experimental SEA (EX) and Adper Prompt (AP) - were measured with three bonding protocols. The D/E resin of All-Bond 2 was applied as the hydrophobic, neutral adhesive. Clearfil SE Bond (SE, self-etching primer system) and All-Bond 2 (AB, total etching system) were used as references. The following protocols were used: (1) EX1 (EX 1 coat); (2) EX2 (EX 2 coats); (3) EX+ (EX 1 coat + D/E resin); (4) AP1 (AP 1 coat); (5) AP2 (AP 2 coats); (6) AP+ (AP 1 coat + D/E resin); (7) SE (SE primer + SE bond); (8) SE+ (SE primer + D/E resin); (9) AB (etching + AB primer + D/E resin). Filtek Z250 composite resin was built up and the microtensile bond strength (MTBS) values of the specimens were compared. The fractured surfaces were observed using SEM. Results : When SEA was used as self-etching primer and hydrophobic, neutral adhesive was applied as well, MTBS was significantly higher than that when either one coat or two coats of SEA only were used (p < 0.05). Conclusion : The hydrophobic, neutral adhesive improved the integrity of the bonded interface obtained with SEA.