• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.71-74
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• 2004

A composite-aluminum hybrid joint of composite external fuel tank of an aircraft has been analyzed by a 3-dimensional finite element method. Curvature and contact of the joint structure were considered in the analysis. Yamada-Sun failure criteria was utilized for the failure evaluation. A finite element program ABAQUS was used for the nonlinear contact analysis. The joint structure was predicted to be safe in both the test and analysis.

• Composites Research
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• v.22 no.2
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• pp.7-13
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• 2009

With the wide application of fiber-reinforced composite material in aero-structures and mechanical parts, the design of composite joint have become a very important research area because they are often the weakest areas in composite structures. In this paper, the failure strengths of the hybrid composite joints which were composed of a combination of an adhesive joint and a mechanical joint were evaluated and predicted. The 10 hybrid joint specimens which have different w/d, e/d and adherend thickness were manufactured and tested. The damage zone theory and the failure area index method were used for the failure prediction of the adhesive joint and the mechanical joint, respectively and the hybrid joints were assumed to be failures if either of the two failure criteria was satisfied. From the results of experiments and analyses, the failure strengths of the hybrid joints could be predicted to within 25.5%.

• Steel and Composite Structures
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• v.9 no.1
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• pp.39-58
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• 2009

Composite joints, considering the composite action of steel and concrete, exhibit, in general, high strength and high ductility. As a consequence, the use of this type of joint has been increasing in many countries, especially in those that are located in earthquake-prone regions. In this paper, a hysteretic model with pinching is presented that is able to reproduce the cyclic response of steel and composite joints. Secondly, the computer implementation and adaptation of the model in a spring element within the computer code Seismosoft is described. The model is subsequently calibrated using a series of experimental test results for composite joints subjected to cyclic loading. Finally, typical parameters for the various joint configurations are proposed.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.110-113
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• 2002

As a preliminary study for the three dimensional failure analysis of composite joints, the three dimensional stress analysis on a pin-loaded unidirectional-fabric hybrid composite joints are performed. The contact and frictions between composite plate and metal bush are considered in the finite element method by NASTRAN. Experiments are conducted to validate the accuracy and feasibility of the finite element technique for 25 specimens with 5 different geometries. The finite element and experimental results show the bush cap induces the unsymmetric deformation, stress distribution, and failure behavior through the thickness. The experiment also shows the failure loads are higher in the joint with bush cap than without it.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.79-82
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• 2003

With the wide application of fiber-reinforced composite material in aero-structures and mechanical parts, the design of composite joint have become a very important research area because they are often the weakest areas in composite structures. In this paper, the failure area index method to predict the failure load of the mechanically fastened composite joint was used and the prediction accuracies of the linear finite element analysis were compared with those of nonlinear finite element analysis.

• Steel and Composite Structures
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• v.20 no.3
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• pp.469-486
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• 2016

Codes EN 1993 and EN 1994 require to take into account actual joint characteristics in the global analysis. In order to implement the semi-rigid connection effects in frame design, knowledge of joint rotation characteristics ($M-{\phi}$ relationship), or at least three basic joint properties, namely the moment resistance $M_R$, the rotational stiffness $S_j$ and rotation capacity, is required. To avoid expensive experimental tests many methods for predicting joint parameters were developed. The paper presents a comprehensive analytical model that has been developed for predicting the moment resistance $M_R$, initial stiffness $S_{j.ini}$ and rotation capacity of the minor axis, composite, semi-rigid joint. This model is based on so-called component method included in EN 1993 and EN 1994. Comparison with experimental test results shows that a quite good agreement was achieved. A computer program POWZ containing proposed procedure were created. Based on the numerical simulation made with the use of this program and applying regression analysis, simplified equations for main joint properties were also developed.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.14-17
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• 2004

A prefabricated composite hollow slab with perforated I-beams was suggested for the replacement of deteriorated concrete decks or the construction of new composite bridges with long-span slabs. Composite slabs with embedded I-beams have considerably higher stiffness and strength. For the application of prefabricated composite slabs to bridges, joints between slabs should satisfy the requirements of the ultimate limit state and the serviceability limit state. In this paper, three types of the detail for loop joints were selected and their structural performance in terms of strength and crack control was investigated through static tests on continuous composite slabs. A main parameter was the detail of the joint, such as an ordinary loop joint and loop joint with additional reinforcements. Even though there was no connection of the steel beams at the joints, the loop joints showed good performance in ultimate strength. In terms of crack control, the loop joint with additional reinforcements showed better performance. In ultimate limit state, the continuous composite slabs showed good moment redistribution and ductility.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.1980-2000
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• 1993

The stresses and torque transmission capabilities of adhesively bonded circular, hexagonal and elliptical lap joints were analyzed by the finite element and compared with the experimental results. The adherends of the joints were composed of carbon fiber/epoxy composite shafts and steel shafts. In calculating the torque transmission capabilities, the linear laminate properties of the composite material and the nonlinear shear properties of the adhesive were used. Using this method, the torque transmission capabilities of adhesively bonded lap joints could be obtained within 10% error compared to the experimental results except some single lap joints. The experiments revealed that the hexagonal joint had the best torque transmission capability from the single lap joints and the double lap joint had better torque transmission than the single lap joint.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.55-60
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• 2010

The honeycomb composite joint structure designed for application to a tilting KTX railroad car body is subjected to bending loads of a cantilever type. Honeycomb sandwich composite panel-joint attached in the real tilting car body was fabricated and sectioned as several beam-joint specimens for the bending test. The fracture behaviors of these specimens under static loads were different from those under cyclic loads. Static bending loads caused shear deformation and fracture in the honeycomb core region, while fatigue cyclic bend loading caused delamination along the interface between the composite skin and the honeycomb core, and/or caused a fracture in the welded part jointed with the steel under-frame. These fracture behaviors could occur in other industrial honeycomb composite joints with similar sub-structures, and be used for improving design parameters of a honeycomb composite joint structure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.8
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• pp.613-618
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• 2013

In this paper a new concept on z-pinning technology named by authors as 'z-pinning patch' will be introduced, which advantage is easy application at manufacturing site of composite structures. Using the trial manufactured z-pinning patch, the z-pinned composite single-lap shear joint specimens were successfully manufactured and tested to check the improvement of joint strengths. The z-pin's material is stainless steel and its surface was machined as zagged shape and chemically corroded to improve joint force with composite materials.