• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2334-2343
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• 2000

This paper proposes an efficient beam-shell modeling technique for the free vibration analysis of a T-joint thin-walled beam structure. Except a small portion of a T-joint which is modeled by shell elements, the structure is modeled by thin-walled beam elements that can describe warping and distortion. In order to match the shell and thin-walled beam elements at the interface of the dissimilar elements, a technique based on a pseudo inverse matrix is formulated. This paper also examines the role of the thin-walled element taking into account the distortion and warping deformation degrees of freedom in predicting accurately the dynamic characteristics of a T-joint thin-walled structure.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.439-445
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• 2012

The stress singularity for the excess adhesive on interface of adhesively bonded joint was investigated by using the 2-dimensional elastic boundary element method (BEM). To establish a reasonable strength evaluation method and a fracture criterion for the excess adhesive of interface in adhesively bonded joint, it is necessary to evaluate fracture parameters with various bonding conditions. Under the variations of adhesively bonded thickness (h) and diameter (d) for the excess adhesive, a stress analysis was performed, and from the results, the stress singularity index (${\lambda}$) and the stress singularity factor (${\Gamma}$) were calculated. The variations have a great influences on the stress singularity for the excess adhesive of interface in adhesively bonded joint, and the ${\Gamma}$ is reduced as the "h" and "d" increase.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.69-74
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• 1997

In this paper we derive relations which describe the geometry and kinematics of contact between the travelling wheel and stepped comb joint. From which we can obtain the impulse, impulsive force and its time interval due to travelling wheel impact which can not be taken from Carter's model or Newland and Cassidy's. The calculated transient responses of the comb joint structure to travelling wheel impact reveals that the proposed wheel contact model and Carter's give very similar results but Newland Cassidy's model make a quite different results from the others.

• Economic and Environmental Geology
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• v.33 no.4
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• pp.309-320
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• 2000

Aperture is an important parameter for determining the hydraulic characteristics of fractured media. In this study the topography of artificial rock joint surface was measured using 3D laser profilometer to analyze the aperture distribution. The initial aperture distribution was determined when the contact area became one percent of total joint surface. The initial aperture distribution of granite joint, with the mean value of 0.78 mm and the standard deviation of 0.34 mm was much different from that of the marble joint, with the mean value of 0.57 mm and the standard deviation of 0.26 mm. Apertures of both granite and marble showed normal distributions. Aperture distribution with the contact area of 25% was also analyzed. Mean value was decreased to one third compared to the initial aperture, but the standard deviation was decreased slightly. To determine the spatial correlation of the aperture distribution variogram analysis was carried out on the initial aperture data. Most experimental variograms were fitted well with exponential model. It is expected that the measured aperture characteristics can be used for stochastic analysis of fluid flow through rock joints.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.289-294
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• 1994

A new type of electrogoniometer to measure the three dimensional motion of the human knee joint was developed. This instrument is composed of six potentiometers: four arranged for two universal joints, one for pin joint, and one for axial rotation measurement. The voltage change in six potentiometers were collected through A/D converter for acquisition, storage and analysis. With a developed instrument, gait analysis was performed. Compared to earlier developed triaxial type goniometer, new instrument shows its convenience in application and accuracy in measurement.

• Journal of Welding and Joining
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• v.18 no.2
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• pp.204-204
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• 2000

There are many weld defects such as surface crack, lack of fusion, and incomplete penetration(IP) in the butt joint weld of the existing steel bridges. The crack-like defects may significantly reduce the life of the structure. This paper presents the procedure and the results of the fatigue life assessment of the butt joints with weld defects in the existing steel girder bridge. The butt joint welds with incomplete penetration were instrumented with strain gages to determine the stress histogram under normal traffic. Based on the measured stress histogram the crack propagation analysis were performed for the fatigue life assessment. By using the suggested procedure and methodology, one can decide the time of periodic inspection and the necessity of repair of the butt joint welds with serious weld defects in the existing steel bridge. (Received October 1, 1999)

• Journal of Welding and Joining
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• v.18 no.2
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• pp.77-85
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• 2000

There are many weld defects such as surface crack, lack of fusion, and incomplete penetration (IP) in the butt joint weld of existing steel bridges. The crack-like defects may significantly reduce the fatigue life of the structure. This paper presents the procedure and the results of the fatigue life assessment of the butt joints with weld defects in the existing steel girder bridge. The butt joint welds with incomplete penetration were instrumented with strain gages to determine the stress histogram under normal traffic. Based on the measured stress histogram the crack propagation analysis were performed for the fatigue life assessment. By using the suggested procedure and methodology, one can decide the time of periodic inspection and the necessity of repair of the butt joint welds with serious weld defects in the existing steel bridge.

• Advances in aircraft and spacecraft science
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• v.5 no.3
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• pp.401-410
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• 2018

The aim of this work is to optimize the geometrical parameters as the adhesive thickness and the beveled angle to reduce the edge effect of the scarf and V bounded joint. A finite element analysis is done to define the generated stresses in the bounded joint. The geometrical optimum is obtained using the Experimental Design Method. Results show that the double scarf (V) joint is better than the simple scarf bounded joint.

• The Journal of Advanced Prosthodontics
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• v.1 no.1
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• pp.26-30
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• 2009

STATEMENT OF PROBLEM. Qualitative and semi-quantitative methods have been developed for TMJ sound classification, but the criteria presented are completely inhomogeneous. Thus, to develop more objective criteria for defining TMJ sounds, electroacoustical systems have been developed. We used Joint vibration analysis in the BioPAK system(Bioresearch Inc., Milwaukee, USA) as the electrovibratography. PURPOSE. The aim of this study was to examine the TMJ sounds with repect to frequency spectra patterns and the integral > 300 Hz /< 300 Hz ratios via six-months follow-up. MATERIAL AND METHODS. This study was done before and after the six-months recordings with 20 dental school students showed anterior disk displacement with reduction. Joint vibrations were analyzed using a mathematical technique known as the Fast Fourier Transform. RESULTS. In this study Group I and Group II showed varied integral > 300 /< 300 ratios before and after the six-months recordings. Also, by the comparative study between the integral > 300 /< 300 ratios and the frequency spectrums, it was conceivable that the frequency spectrums showed similar patterns at the same location that the joint sound occurred before and after the six-months recordings. while the frequency spectrums showed varied patterns at the different locations that the joint sound occurred before and after six-month recordings, it would possibly be due to the differences in the degree of internal derangement and/or in the shape of the disc. CONCLUSIONS. It is suggested that clinicians consider the integral > 300 /< 300 ratios as well as the frequency spectrums to decide the starting-point of the treatment for TMJ sounds.

• Journal of Korean Medicine Rehabilitation
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• v.29 no.1
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• pp.7-20
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• 2019

Objectives The purpose of this study was to improve the comfort of daily life such as reduction of headache and increase of movement of neck by using muscle relaxation approach and joint movement approach for office worker with tension type headache of foward head posture sitting over 5 hours. Methods For this, 9 male and 15 female participated in the foward head posture with tension type headache. Each group consisted of 3 male and 5 female. Groups are divided into groups, such as muscle relaxation therapy, joint movement therapy, muscle relaxation and joint movement therapy. After intervention for each group for a month, we measured neck movement and head disability index and neck disability index 2 week. SPSS 23.0 (IBM Corp., Armonk, NY, USA) was used for data analysis. The one-way repeated analysis of variance (ANOVA), one-way ANOVA, compared t-test was used for statistical analysis. Results Three intervention groups have brought improvements in neck movement and daily life comfort. There is significant difference in the improvement of neck extension and change in neck disability index between 2 and 4 weeks in the joint movement approach compared to muscle relaxation approach, muscle relaxation and joint movement approach. Conclusions Office workers are exposed to tension type headache. However, muscle relaxation approach and joint movement approach can improve neck movement and daily life comfort.