• Composites Research
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• v.17 no.6
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• pp.14-21
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• 2004

Failure process, mode and strength of unidirectional composite single lap bonded joints were investigated experimentally with respect to bonding methods, those are, co-curing with and without adhesive and secondary bonding. The co-cured joint specimens without adhesive had the largest failure strength. Progressive failures along the adhesive layer occurred in the secondary bonded specimens. In the co-cured specimens with adhesive film which had better material strength and adhesion performance, delamination failure occurred and the joint strengths were less than those of secondary bonded specimens. Delamination failure did not occur in the secondary bonded specimens because of earlier crack growth and progressive failure in the adhesive layer. Therefore, failure strength of composite bonded Joints were not always proportionate to material strength and adhesion performance of the adhesive due to the weakness of delamination in composite materials. The effects of surface roughness, bondline thickness and fillets were also studied on secondary bonded specimens.

• Composites Research
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• v.28 no.3
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• pp.89-93
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• 2015

This study analyzes the transplanting parts used as the graft of artificial knee joint. The low elastic titanium alloy is applied to clear up the stress shield effect. The simulation analysis is carried about the stress distribution of the transplanting parts. The correlation with frame is inferred and investigated through the equivalent stress distribution of titanium alloy due to elastic modulus. The stress of the transplanting parts decreases as the elastic modulus decreases at the first time. It decreases greatly near the stress of 46 GPa and increases again. Because the stress happened at the transplanting parts decreases, more stress is applied on the frame. This phenomenon is the stress shield effect. The result of this study can be thought to be necessary to develop the safe design of composite material.

• Composites Research
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• v.24 no.5
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• pp.23-28
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• 2011

In this paper, the bonding strengths of co-cured T800 carbon/epoxy composite-aluminum single lap joints with and without additional pressures were investigated using the pressure information induced by the fiber tension during a filament winding process. The specimens of all the tests were fabricated by an autoclave vacuum bag de-gassing molding being controlled forming pressures (absolute pressures of 0.1MPa, 0.3MPa and 0.7MPa including vacuum). A special device which can act uniform additional pressures on the joining part of the single lap joint specimen was designed to measure the bonding strengths of composite-aluminum liners of type III hydrogen pressure vessel fabricated by a filament winding process. After the three different additional pressures (absolute pressures of 0.1MPa, 0.3MPa and 0.7MPa) were applied to the specimens the effect of the additional pressures on the bonding strengths of the co-cured single-lap joints were evaluated.

• Composites Research
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• v.12 no.5
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• pp.98-109
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• 1999

An investigation has been performed to develop a nonlinear finire element method for the analysis of the long-term behavior of an artificial hip joint. The three dimensional multi-layered brick element is used to analyze the design performances of hip prodtheses with various materials and the thick laminated composite hip prostheses with various layup sequences. The used element can accommodate the varying material properties of the element and allow the ply-drop-off along the eleement edge. The nonlinear finite element analysis program has been verified by the comparison with the exact solution of the bean problem subjected to uniaxial loading. By using the program, the density changes and strength ratios of artificial hip joint are calculated according to the hip prosthesis materials and the layers of composite hip prosthesis. The numerical results are easily applied to evaluate design performances of a hip prosthesis, and decrease the difficulty and time of hip prosthesis design.

• Composites Research
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• v.34 no.2
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• pp.101-107
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• 2021

Composite structures have components and joints. Theses connections or joints can be potentially weak points in the structure. The failure mode of the composite bolted joint is designed as a bearing failure mode for structural safety. The load-displacement relation exhibits bearing failure mode shows a nonlinear behavior after the initial failure and progressive failure behavior. In order to accurately predict the failure behavior of composite bolted joints, this study modified the shear damage variable calculation process in the existing progressive failure analysis model. The results of the bearing stress-bearing strain of the composite bolted joint were predicted using the modified progressive failure analysis model, and the modified model was verified through comparison with the previous progressive analysis model.

• Composites Research
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• v.19 no.4
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• pp.15-22
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• 2006

One of the primary factors limiting the application of composite-metal adhesively bonded joints in structural design is the lack of a good evaluation tool for the interfacial strength to predict the load bearing capacity of boned joints. In this paper composite-steel adhesion strength is evaluated in terms of stress intensity factor and fracture toughness of the interface corner. The load bearing capacity of double lap joints, fabricated by co-cured bonding of composite-steel adherends has been determined using fracture mechanical analysis. Bi-material interface comer stress singularity and its order are presented. Finally stress intensities and fracture toughness of the wedge shape bi-material interface corner are determined. Double lap joint failure locus and its mixed mode crack propagation criterion on $K_1-K_{11}$ plane have been developed by tension tests with different bond lengths.

• Computers and Concrete
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• v.19 no.4
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• pp.405-411
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• 2017

Carbon Fiber Reinforced Plastic (CFRP) has commonly been used to strengthen existing RC structures. Wrapping the whole component with CFRP is an effective method and simple to execute. Besides, specific configuration of CFRP sheets (L, X and T shape) has also been considered in some experiments to examine CFRP effects in advance. This study aimed to provide an optimal CFRP configuration to effectively retrofit the beam-column connection using continuous material topology optimization procedure. In addition, Moved and Regularized Heaviside Functions and penalization factors were also considered. Furthermore, a multi-material procedure was also used to compare with the results from the single material procedure.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.72-77
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• 2003

Nano-diamonds were added to Ultra-high molecular weight polyethylene (UHMWPE) to improve the tribological properties of UHMWPE. Nano-diamonds which have a diameter of about 5-10nm were produced by detonation. UHMWPE/nano-diamonds composites were fabricated by hot pressing method. It is shown that friction coefficient was increased and wear resistance was improved as nano-diamonds were added to UHMWPE because of excellent mechanical properties of nano-diamonds located on UHMWPE surface.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.27-34
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• 2004

Tail-wing, gondola and thrust motor mount(EMS) were built by carbon/glass fiber composites. Structural strength & stiffness was verified by specimen tests. Static strength tests for each structural components were conducted separately. Boundary conditions are specially designed for each components to simulate exact joint conditions. Tests shows no detriment deformation at 100% DLL and no failure at 150% DLL.

• Composites Research
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• v.25 no.1
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• pp.14-18
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• 2012

The structural adhesives have the advantage of improving automobile performances and are being applied to joining light weight materials like aluminium and composite. In order to characterize the impact behavior of structural adhesive, instrumented impact tests were performed with respect to pin-ring adhesively bonded joint specimens. Also dynamic FE analysis was carried out using LS-DYNA to compare the results with experiments.