• Proceedings of the KSME Conference
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• 2004.11a
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• pp.226-231
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• 2004

Press fitting method for joining of a hybrid tube and steel ring with small teeth for automotive aluminum/composite hybrid propeller shaft was devised to improve reliability and to reduce manufacturing cost, compared to other joining methods such as an adhesively bonded joint, bolted joint or welded joint. To obtain high strength of the press fit joint, an optimal design method for the teeth was devised with respect to number and shape of the steel teeth. Torsional static, fatigue tests and finite element analysis of the press fit joint were performed with respect to experimental variables. The developed optimal design method predicted well the static torque capability and failure mode of the press fit joint. Also, it provided design guide line of press fit joint for improving torsional static and fatigue characteristics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1350-1353
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• 2007

An experimental method based on contact resonance is developed to extract the contact parameters of mechanical joints under various clamped conditions. Mechanical joint parameters of shear contact stiffness and damping were extracted for different physical joint parameters such as surface finish of the mating surfaces, the presence of lubrication, the effect of the clamping pressure, and shear load. It was found that the shear contact stiffness values decreased with increasing clamping load and increased with increasing shear loading. Contact damping ratio values were almost constant with clamping load, but decreased with increasing shear load. Moreover, rough surfaces exhibited the highest shear stiffness and contact damping compared to smooth surfaces.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.774-777
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• 2002

There are various methods to join mechanical structures together. They typically include welding, mechanical joints by bolts and other processes depending on specific needs. Analyses of joints in the mechanical structures are essential in understanding the dynamic characteristics of the structures. In this research an impulse technique is applies to investigate the dynamic behavior of joints produced by bolts. The length overlap in the joints was varied as the number of the bolts in the joins was changed. Also, the torque applied to the bolts were adjusted. Resonance frequencies were determined for the joints to evaluate the relationship between the increase in the applied torque and the increase in the number of bolts used in the joints. The results have demonstrated that the resonance frequencies of the joints increase with the increasing torque.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.561-567
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• 2007

This paper deals with the numerical model of a bracing-friction damper system and its deployment using the optimal slip load distribution for the seismic retrofitting of a damaged building. The Slotted Bolted Connection (SBC) type friction damper system was tested to investigate its energy dissipation characteristic. Test results coincided with the numerical ones using the conventional model of a bracing-friction damper system. The placement of this device was numerically explored to apply it to the assumed damaged-building and to evaluate its efficiency. It was found by distributing the slip load that minimizes the given performance indicies based on structural response. Numerical results for the damaged building retrofitted with this slip load distribution showed that the seismic design of the bracing-friction damper system under consideration is effective for the structural response reduction.

• Structural Engineering and Mechanics
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• v.6 no.5
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• pp.571-582
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• 1998

Testing of steel roof purlins is usually performed on full scale models in large vacuum test rigs. To undertake a comparison between web cleat connected purlins and flange bolted purlins a series of tests were performed on a 1:4 small scale model vacuum test rig. Various modelling issues need to be addressed to ensure reasonable comparison with actual constructed roof framing methods but still be suitable for an economical comparison between the connection methods. Model test results were supported by, and found to be in reasonable agreement with, deflection predictions from computer models based on finite element methods. This paper discusses the testing methods adopted and the value of small scale model testing programs as a means of obtaining comparisons between framing options.

• Steel and Composite Structures
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• v.2 no.4
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• pp.247-258
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• 2002

The high-temperature material properties of steel are very important to the fire resistance analysis of high-strength bolt connections. This paper reports on the results of the experimental studies on the high-temperature properties of 20 MnTiB steel which is widely used in high-strength bolts, and the friction coefficient of 16Mn steel plates at elevated temperature which is a necessary parameter for bolted frictional connection analysis. The test data includes yield strength, limit strength, modulus of elasticity, elongation and expansion coefficient of 20MnTiB steel at elevated temperature, and the friction coefficients between two 16Mn steel plates under elevated temperatures and after cooling. Based on the data from the tests, the mathematical models for predicting the mechanical properties of 20MnTiB steel and friction coefficients of 16Mn steel plates have been established.

• Structural Engineering and Mechanics
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• v.10 no.3
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• pp.211-226
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• 2000

A procedure has been developed for bolting steel plates to the sides of existing reinforced concrete beams which can be used to increase the shear strength of beams, increase the flexural strength of beams with enhanced ductility or with only a small loss of ductility, and increase the stiffness of beams in order to reduce deflections and crack widths. It will be shown in this paper, through a qualitative analysis and through the results of testing eight large scale beams, that standard rigid plastic analysis techniques which are commonly used in the design of reinforced-concrete, steel, and composite steel and concrete beams cannot be used directly to design composite bolted-plated reinforced-concrete beams. In the companion paper, quantitative procedures will be used to adapt the standard rigid plastic analysis techniques for this relatively new form of retrofitting.

• Structural Engineering and Mechanics
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• v.2 no.3
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• pp.295-309
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• 1994

The present paper concerns the mathematical study and the numerical treatment of the problem of semirigid connections in bolted steel column base plates by taking into account the possibility of appearance of separation phenomena on the contact surface under certain loading conditions. In order to obtain a convenient discrete form to simulate the structural behaviour of a steel column base plate, the continuous contact problem is first formulated as a variational inequality problem or, equivalently, as a quadratic programming problem. By applying an appropriate finite element scheme, the discrete problem is formulated as a quadratic optimization problem which expresses, from the standpoint of Mechanics, the principle of minimum potential energy of the semirigid connection at the state of equilibrium. For the numerical treatment of this problem, two effective and easy-to-use solution strategies based on quadratic optimization algorithms are proposed. This technique is illustrated by means of a numerical application.

• Steel and Composite Structures
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• v.6 no.2
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• pp.139-157
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• 2006

In this paper, a cyclic mechanical model is presented to simulate the behaviour of top and seat with web angle beam-to-column connections. The introduced mechanical model is compared with Eurocode 3 Annex J, its extension, and with experimental data. To have a better insight regarding the actual response of the joints, available results of the experiments, carried out on full-scale top and seat angle joints under monotonic and cyclic loading, are first considered. Subsequently, a finite element model of the test setup is developed. The application of the proposed model, its comparisons with the experimental curves and with the Eurocode 3 Annex J and with its modification, clearly show the excellent quality of the model proposed.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.307-310
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• 2005

The PCS system, which consists of precast concrete column and steel beam, has been under development. Experimental test has been carried out to investigate the structural performance of the system under earthquake. Two types of test specimens of beam-column joints are designed in order to compare the performances. One is the system with reinforced concrete slab and the other is without slab. It is found that the system with slab could satisfy all of the requirements from ACI Criteria such as strength, stiffness degradation and energy dissipation capacity except initial stiffness. It is also investigated that the stiffness of the joint is belong to rigid joint type according to Bjorhovde criterion. And it is observed that the partial-composite system between beam and slab is more effective than full-composite system in the respect of the energy dissipation capacity of the system.