• International Journal of Korean Welding Society
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• v.4 no.1
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• pp.53-60
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• 2004

Adhesive-bonded joints are widely used in the industry. Recently, applications of adhesive bonding joints have been increased extensively in automobile and aircraft industry. The strength of adhesive joints is influenced by the surface roughness, adhesive shape, stress distribution, and etc. However, the magnitude of the influence has not yet been clarified because of the complexity of the phenomena. In this study, as the fundamental research of adhesive bonding joints, the effects of adhesive shape and loading speed on bonding strength properties and durability of aluminum to polycarbonate single-lap joints were studied. To evaluate the effect of adhesive shape, several modified shapes were used, and loading speeds were varied from 0.05 to 5mm/min. As a result, the load distribution showed a brittle fracture tendency. The trigonal edged single lap and bevelled lap joints showed the higher strength than the plain single lap, trigonal single lap, joggle lap and double lap joints in same adhesive area. The fractures of trigonal single lap and trigonal edged single lap joints that had the higher strength level were shown as the mixture type of the cohesive and interfacial-failure, mostly joggle lap joints that had the lower strength level were shown as the adhesive-failure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.4
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• pp.905-915
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• 1998

Static tensile tests using adhesive-bonded single-lap joints of aluminum alloy were conducted to investigate the effect of geometric factor, overlap length, adherend thickness, adhesive thickness and material composition of adherend/adhesive on the strength of adhesive joint. The average applied shear stress at joint fracture decreased with increasing lap length. However increasing the adherend thickness resulted in a higher joint strength. Higher yield strength of adherend and lower elastic modulus of adhesive is advantageous to the adhesive joint. Newly proposed modified joint factor could be well evaluated the influence of lap length, adherend thickness and adhesive thickness on the bond strength for adhesive joints.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.6
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• pp.783-790
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• 2004

Adhesive-bonded joints are widely used in the industry. Recently, applications of adhesive bonding joints have been increased extensively in automobile and aircraft industry. The strength of adhesive joints is influenced by the surface roughness, adhesive shape, stress distribution, and etc. However, the magnitude of the influence has not yet been clarified because of the complexity of the phenomena. In this study, as the fundamental research of adhesive bonding joints, the effects of adhesive shape and loading speed on bonding strength properties and durability of aluminum to polycarbonate single-lap joints were studied. To evaluate the effect of adhesive shape, several modified shapes were used, and loading speeds were varied from 0.05 to 5 mm/min. As a result, the load-displacement distribution was shown a brittle fracture tendency. The trigonal edged single lap and bevelled lap joints showed the higher strength than the plain single lap, trigonal single lap, joggle lap and double lap joints in same adhesive area. The fractures of trigonal single lap and trigonal edged single lap joints that had the higher strength level were shown as the mixture type of the cohesive and interfacial-failure, mostly joggle lap joints that had the lower strength level were shown as the adhesive-failure.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.124-130
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• 2009

This study presents a finite element simulation of elastic waves for detecting anti-symmetric damages in an adhesively-bonded single lap joint. Plane strain elements were used for modeling adherents (aluminum) and adhesives (epoxy). Three types of damage were introduced: thickness reduction, elasticity deterioration, and voids in the adhesive layers, and two excitation and reception arrangements (ER1 and ER2) were used to investigate the detectability of the damage. The simulation showed that symmetrically located damage, such as a thickness reduction, can be detected by one excitation and one reception arrangement (ER1) and anti-symmetric damages, such as elasticity deterioration and voids, can be detected by modified two-point elastic wave excitation (ER2). Compared with the ER1 arrangement, the ER2 arrangement does not require a baseline signal for damage detection; hence, an efficient method of anti-symmetric damage detection in an adhesively-bonded single lap joint is proposed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.2
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• pp.111-118
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• 2010

The joints are often the weakest areas in composite structures. In this paper, the thick aluminum-aluminum joint specimens and thick composite-aluminum single lap adhesive joint specimens were manufactured and the tensile tests were performed. The fracture mode of each specimen was investigated and the modified damage zone theory based on the yield strain was proposed and compared with experimental failure load of each mode. The failure loads of the thick aluminum-aluminum joint and composite-aluminum joint were predicted by the same failure criterion and they could be predicted to within 19.3% using the damage zone ratio method for all 14 cases investigated.

• Advances in aircraft and spacecraft science
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• v.11 no.1
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• pp.83-103
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• 2024

Adhesive bonding is currently widely used in many industrial fields, particularly in the aeronautics sector. Despite its advantages over mechanical joints such as riveting and welding, adhesive bonding is mostly used for secondary structures due to its low peel strength; especially if it is simultaneously exposed to temperature and humidity; and often presence of bonding defects. In fact, during joint preparation, several types of defects can be introduced into the adhesive layer such as air bubbles, cavities, or cracks, which induce stress concentrations potentially leading to premature failure. Indeed, the presence of defects in the adhesive joint has a significant effect on adhesive stresses, which emphasizes the need for a good surface treatment. The research in this field is aimed at minimizing the stresses in the adhesive joint at its free edges by geometric modifications of the ovelapping part and/or by changing the nature of the substrates. In this study, the finite element method is used to describe the mechanical behavior of bonded joints. Thus, a three-dimensional model is made to analyze the effect of defects in the adhesive joint at areas of high stress concentrations. The analysis consists of estimating the different stresses in an adhesive joint between two 2024-T3 aluminum plates. Two types of single lap joints(SLJ) were analyzed: a standard SLJ and another modified by removing 0.2 mm of material from the thickness of one plate along the overlap length, taking into account several factors such as the applied load, shape, size and position of the defect. The obtained results clearly show that the presence of a bonding defect significantly affects stresses in the adhesive joint, which become important if the joint is subjected to a higher applied load. On the other hand, the geometric modification made to the plate considerably reduces the various stresses in the adhesive joint even in the presence of a bonding defect.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.11
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• pp.929-935
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• 2015

The long neck flange is used to connect piping arrangements where the lap joint is applied. Generally, the component can be manufactured by welding, but this method is both time and cost intensive. Embrittlement at the heat affected zones was also considered. A spinning method developed to improve the manufacturing process and solve the problems of welding. The flange area of the long neck flange can be formed by changing the direction of the metal flow, from axial to radial, while maintaining pressure by using an outer mold and a lap roller. A modified process was additionally developed using a round roller rather than the outer mold. In this modification, the round roller can form the shape of all sizes of long neck flange. Using these flexible methodologies, the cost to prepare outer molds and the time to install and remove the molds can be significantly reduced.

• Advances in aircraft and spacecraft science
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• v.1 no.1
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• pp.1-14
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• 2014

Physico-chemical changes of the plasma modified titanium alloy [Ti-6Al-4V] surface were studied with respect to their crystallographic changes by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM).The plasma-treatment of surface was carried out to enhance adhesion of high performance nano reinforced epoxy adhesive, a phenomenon that was manifested in subsequent experimental results. The enhancement of adhesion as a consequence of improved spreading and wetting on metal surface was studied by contact angle (sessile drop method) and surface energy determination, which shows a distinct increase in polar component of surface energy. The synergism in bond strength was established by analyzing the lap-shear strength of titanium laminate. The extent of enhancement in thermal stability of the dispersed nanosilica particles reinforced epoxy adhesive was studied by Thermo Gravimetric Analysis (TGA), which shows an increase in onset of degradation and high amount of residuals at the high temperature range under study. The fractured surfaces of the joint were examined by Scanning electron microscope (SEM).

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.747-752
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• 1999

The interfacial reaction and joint properties of Sn-3.5Ag/Cu and Sn-3.5Ag-1Zn/Cu joint were studied. Modified double lap shear solder joints of Sn-3.5Ag and Sn-3.5Ag- lZn solder were aged for 60days at $100^{\circ}C$ and $150^{\circ}C$ and then loaded to failure in shear. The Sn-3.5Ag/Cu had a fast growth rate of the reaction layer in comparison with the Sn-3.5Ag-lZn at the aging temperature of $150^{\circ}C$ Through the SEM/EDS analysis of solder joint, it was proved that intermatallic layer was $Cu_{6}Sn_5$ phase and aged specimens showed that intermatallic layer grew in proportion to $t_{1/2}$, and the precipitate of $Ag_3Sn$ occur to both inner layer and interface of layer and solder. In case of Zn-containing composite solder, $Cu_{6}Sn_{5}$ phase formed at the side of substrate and $Cu_{5}Zn_{8}$ phase formed at the other side in double layer. The shear strength of the Sn-3.5Ag/Cu joint improved by addition of IZn. The strength of the joint increases with strain rate and decreases with aging temperature

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.6
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• pp.732-746
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• 2003

Statement of problem. Soft lining materials, also referred to as tissue conditioning materials, tissue heating materials, relining materials, soft liners or tissue conditioners, were first introduced to dentistry by a plastic manufacturer in 1959. Since the introduction of the materials to the dental field, their material properties have been continually improved through the effort of many researchers. Soft lining materials have become widely accepted, particularly by prosthodontists, because of their numerous clinical advantages and ease of manipulation. Unfortunately, few reports have been issued upon the topic of increasing the bond strength between the base metal alloy used in cast denture bases and PMMA soft liner modified with 4-META, nor upon the pattern of debonding and material change in wet environment like a intra oral situation. Purpose. The purposes of this study were comparing the bond strength between base metal alloy used for the cast denture bases and PMMA soft liner modified with 4-META, and describing the pattern of debonding and material property change in wet environment like the intraoral situation. Material and Methods. This study consisted of four experiments: 1. The in vitro measurement of shear bond strength of the adhesive soft liner. 2. The in vitro measurement of shear bond strength of the adhesive soft liner after 2 weeks of aging. 3. A comparison of debonding patterns. 4. An evaluation the Relation time of modified soft liner. The soft liner used in this study was commercially available as Coe-soft (GC America.IL.,USA), which is provided in forms of powder and liquid. This is a PMMA soft liner commonly used in dental clinics. The metal primer used in this study was 4-META containing primer packed in Meta fast denture base resin (Sun Medical Co., Osaka, Japan). The specimens were formed in a single lap joint desist which is useful for evaluating the apparent shear bond strength of adhesively bonded metal plate by tensile loading. Using the $20{\times}20mm$ transparent grid, percent area of adhesive soft liner remaining on the shear area was calculated to classify the debonding patterns. To evaluate the change of the initial flow of the modified adhesive soft liner, the gelation time was measured with an oscillating rheometer (Haake RS150W/ TC50, Haake Co., Germany). It was a stress control and parallel plate type with the diameter of 35mm. Conclusion. Within the conditions and limitations of this study, the following conclusions were drawn as follows. 1. There was significant increase of bond strength in the 5% 4-META, 10% 4-META containing groups and in the primer coated groups versus the control group(P<0.05). 2. After 2 weeks of aging, no significant increase in bond strength was found except for the group containing 10% 4-META (P<0.05). 3. The gelation times of the modified soft liner were 9.3 minutes for the 5% 4-META containing liner and 11.5 minutes for the 10% 4-META liner. 4. The debonding patterns of the 4-META containing group after 2 weeks of aging were similar to those of immediaely after preparation, but the debonding pattern of the primer group showed more adhesive failure after 2 weeks of aging.