• Composites Research
• /
• v.16 no.4
• /
• pp.10-21
• /
• 2003

Proposed is a new method to determine the characteristic lengths for the failure analysis of composite joint without experiments. New method uses the result that the stress distribution in the characteristic length specimens is linearly proportional to the applied load. The compressive characteristic lengths calculated by the present method are exactly same as the lengths obtained by the conventional method based on experiment. The new tensile characteristic length is defined using the strength of the notched laminate, while previous methods use the strength of the sound laminate. That change allows calculating the tensile characteristic length numerically without experiment like the compressive characteristic length. Finite element analyses are conducted by MSC/NASTRAN. The interface between the fastener and laminate is modeled by the contact surface element. The finite element results based on the new characteristic lengths show the excellent agreement with experimental results for the Graphite/Epoxy composite .joints.

• Korean Journal of Applied Biomechanics
• /
• v.22 no.4
• /
• pp.413-419
• /
• 2012

The purpose of this study was to investigate the effects of increased saddle height on the length and activity pattern of vastus lateralis (VL) and biceps femoris (BF) muscle. To compare the effects of increased saddle height, Preferred (self-selected height of subject) and High saddle height (approximately 5% higher saddle height than self-selected) were used. Seven elite cyclists (career: $16.1{\pm}8.5years$) participated in 3 min. sub-maximal pedaling tests under the same cadence (90 RPM) and pedaling power (150 W). Hip and knee joint angles, and the length and activity of VL and BF were compared by measuring 3D motion and electromyography (EMG) data. Results showed that there were significant differences in peak extension timing of the hip joint angle and the range of motion of the hip and knee joint between different saddle heights. Although there were significant differences in muscle length of both muscles with increasing saddle height, the timing and amount of muscle activity differed only at the BF. These findings suggest that the timing and amount of bi-articular muscle activity (i.e. BF) can be altered by changing the saddle height. For practically applying these results, further study is necessary to evaluate the effects of various cadence and the pedaling power with various saddle heights.

• Journal of Adhesion and Interface
• /
• v.7 no.4
• /
• pp.18-23
• /
• 2006

The influence of the notch length on the stress distribution of mid-bondline and adherend was investigated using elasto-plastic finite element method. The results from the simulation showed that peak stress of mid-bondline decreased markedly as adherend with notch in the middle of lap zone, and the stress in the middle of joint with low stress originally increased evidently. All the peak stresses decreased firstly and increased again as the length of notch increased. The relative higher peak stress appeared at the point near the notch of adherend where might be failed previously during the loading procedure.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2000.10a
• /
• pp.47-52
• /
• 2000

F.R.P specimens were made by mixture CM(chopped mat) 450-104 matrix & RC(roving clothes)570-100 Roving, the mixture ratio Resin: hardener (92:8) for tensile test. It was also made of plates by hand lay-up method and was been cured for 24 hours and then was cut tensile specimens in accordance with ASTM D638 Type 3. Knowing exact behavior of bonded area's stress and strain when the tensile test was going on, the test specimens were made of 2 plies laminae of F.R.P in each for supporting cut part in middle of specimen length. And in middle part also were covered of F.R.P plies of 1/2, 2/3 length of specimen in each as well. Also we consider shear stress in adhered area. This study reveals that as plys length is more longer, rupture stress grows remarkably larger.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.781-787
• /
• 2004

Where the track is continuously welded over a bridge, the longitudinal force is interacted between the track and the sub-structure. Due to this respect, the expansion joint is used to decrease this force. But the expansion joint has several problems related to passenger comfort and maintenance etc. In this study, it is analysed about how the stability of the track is affected as the span length becomes longer in case of 2-span continuos bridge. It is found that there is no problem of an stability unless the span length is longer than 90m when the elastic shoe is used. And several parametric studies were also implemented.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.26 no.1
• /
• pp.73-78
• /
• 2020

Background: The leg length discrepancy (LLD) have been implicated with degenerative diseases since the early 1970s, which also causes musculoskeletal asymmetry problems. The LLD appears due to factors such as balance ability, response time, and muscle strength between the shorter and longer leg. In this study, the effect of manual therapy to LLD has been studied. Methods: Manual therapy has been applied on shorter leg of 30 patients with LLD. The manual therapy was conducted for 2~3 minutes 3 times a week for 4 weeks. Results: The leg length of shorter leg were measured at initial baseline and after 4 weeks. the average leg length of shorter leg increased from 94.10 cm to 94.33 cm. Conclusion: This paper reports that the manual therapy has positive effects on LLD. It was studied by conducting manual therapy on muscles and joints related to shorter leg. In the future, the muscles and joints of the longer leg should be considered and various age group should be studied to develop the understanding of the effect of manual therapy on LLD.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.1
• /
• pp.325-339
• /
• 2018

In this paper, we propose a joint adaptive combining and variable tap-length multiuser detector (MUD) for amplify-and-forward (AF) underwater acoustic cooperative interleave-division multiple access (IDMA) communication system. The proposed MUD jointly realizes tap-length adjustment, adaptive combining, and multiuser detection. In contrast to the existing methods, the proposed detector can adaptively combine the received signals from different nodes at destination, and does not need the assumption that full and perfect channel state information (CSI) of all the links at the receiver is known. Moreover, the proposed detector can adaptively adjust the tap coefficient vector and tap-length of each branch according to the specific channel profile of each branch. Simulation results validate the feasibility and show the advantages of the proposed detector against existing counterparts.

• Korean Journal of Acupuncture
• /
• v.25 no.3
• /
• pp.1-14
• /
• 2008

Objectives : Weights and measures (度量衡) in Korean traditional medicine have been changed in many dynasties and countries. Thus, measurements of chon (寸) and cheok (尺) have been considered as symbolical meaning in recent studies on meridians and acupoints. The present study was made to settle up standard measurement by surveying length of each parts of upper limb as follows. Methods : To calculate length of 1 chon (寸), the length of each part was divided into the numbers of chon (寸) as shwon in ${\ll}$Goldo Hwangjenaegyeong-yeongchu (靈樞 骨度篇)${\gg}$; the chon (寸) length in ${\ll}$Goldo Hwangjenaegyeong-yeongchu (靈樞 骨度篇)${\gg}$ was compared with the chon (寸) length which is calculated by dividing human average hight into 75 chon. Results : Increment of length of 1 chon (寸) did not change as increment of height in subjects. Length of 1 chon (寸) in height is representative of length of 1 chon (寸) in each parts of upper limb. Conclusions : We suggest that most suitable length of 1 chon (寸)for the standard measurement of acupoint location is 2.20 ${\pm}$ 0.17 cm based on length of elbow joint to wrist joint.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.10a
• /
• pp.231-237
• /
• 2001

This paper presents some proposed methods for discontinuum analysis with rock discontinuities data acquisited in tunnel design stage. The limit equilibrium method for rock block sliding and falling proposed in this paper can consider the tunnel excavation and support stage, and, to the extent, the standard deviations and means of joint set orientation. Simple Distinct Elemet modelling methods are recommended in estimating the stability of tunnels in jointed rock masses. Because, the simple models are likely to show more consistent and clear than very complex model with finite joint length and joint deviation parameters.

• Journal of the Ergonomics Society of Korea
• /
• v.32 no.3
• /
• pp.245-252
• /
• 2013

Objective: This paper analyzes the changes on stride parameters, joint angles, and trajectories of the body parts due to high heels during walking and explains the causal relationship between the changes and high heels. Background: This study aims to indicate the comprehensive gait changes by high heels on the whole body for women wearing high heels and researchers interested in high-heeled walking. Method: The experiment was designed in which two different shoe heel heights were used for walking (1cm, 9.8cm), and twelve women participated in the test. In the experiment, 35 points on the body were tracked to extract the stride parameters, joint angles, and trajectories of the body parts. Results: Double support time increased, but stride length decreased in high-heeled walking. The knee inflexed more at stance phase and the spine rotation became more severe. The trajectories of the pelvis, the trunk and the head presented outstanding fluctuations in the vertical direction. Conclusion: The double support time and the spine rotation were changed to compensate instability by high heels. Reduced range of motion of the ankle joint influenced on the stride length, the knee flexion, and fluctuations of the body parts. Application: This study can provide an insight of the gait changes by high heels through the entire body.