• Title/Summary/Keyword: strength control

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Structural Design of an Upper Control Arm, Considering Static Strength (정강도를 고려한 상부 컨트롤 암의 구조설계)

  • Song, Byoung-Cheol;Park, Han-Seok;Kwon, Young-Min;Kim, Sung-Hwan;Park, Young-Chul;Lee, Kwon-Hee
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.1
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    • pp.190-196
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    • 2009
  • This study proposes a structural design method for the upper control arm installed at the rear side of a SUV. The weight of control arm can be reduced by applying the design and material technologies. In this research, the former includes optimization technology, and the latter the technologies for selecting aluminum as a steel-substitute material. Strength assessment is the most important design criterion in the structural design of a control arm. At the proto design stage of a new control arm, FE (finite element) analysis is often utilized to predict its strength. This study considers the static strength in the optimization process. The inertia relief method for FE analysis is utilized to simulate the static loading conditions. According to the classification of structural optimization, the structural design of a control arm is included in the category of shape optimization. In this study, the kriging interpolation method is adopted to obtain the minimum weight satisfying the strength constraint. Optimum designs are obtained by ANSYS WORKBENCH and the in-house program, EXCEL-kriging program. The optimum results determined from the in-house program are compared with those of ANSYS WORKBENCH.

Development of One-Piece Lower Control Arm Based on Taguchi Optimization Method (다구찌 최적화 방법을 이용한 단판형 로어암 개발)

  • Oh, Seung-Taik;Lee, Doo-Hwan;Han, Do-Suck;Jang, Yong-Min;Kim, Dae-Yong
    • Transactions of Materials Processing
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    • v.17 no.8
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    • pp.613-618
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    • 2008
  • As one way of cost innovation and weight saving of the automobile, the one-piece typed lower control arm was developed for the purpose of replacing the box typed lower control arm. In order to overcome less buckling strength of the one-piece typed lower control arm, the design parameters such as the high strength steel grade, the thickness and the shape of main panel were optimized based on Taguchi method.

The Effects of Community-based Exercise Program to Improve Leg Muscle Strength and Balance for Elderly Women (노인여성의 하지근력 및 평형성 향상을 위한 지역사회 운동프로그램의 효과)

  • Kim, Nan-Soo;Kim, Jong-Soon;Lee, Hyun-Ok
    • Journal of the Korean Society of Physical Medicine
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    • v.5 no.4
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    • pp.569-576
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    • 2010
  • Purpose : This study was aimed at determining the effects of community-based exercise program to improve leg muscle strength and balance for elderly women. Methods : This study was nonequivalent control group pre-post test design. Subjects were assigned to two different groups(exercise group=11, control group=7). Exercise group performed community-based exercise program for 8 weeks. Outcome measures included leg muscle strength, balance, walking velocity, activities of daily living(ADL), exercise self-efficacy and health-related quality of life(QoL). The collected data analyzed by independent t-test and paired t-test. Results : Leg muscle strength, walking velocity and mental component summary(QoL) were significantly improved in the exercise group. But balance and exercise self-efficacy were significantly worsened in the control group. There were no significant difference between groups after 8 weeks of community-based exercise. Conclusion : These results suggested that the community-based exercise program is effective for elderly women in improving leg muscle strength, walking velocity and mental component summary(QoL).

Spatting Resistance of High Strength RC Column Covering Spray-on Materials of Fiber Composite Spray Mortar(FCSM) (섬유복합모르터의 뿜칠마감에 의한 고강도콘크리트 기둥부재의 폭렬방지)

  • Song Yong-Won;Han Dong-Yeob;Lee Gun-Cheol;Goh Kyoung-Taek;Kim Jin-Soo;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2006.05a
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    • pp.5-8
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    • 2006
  • High strength concrete has been increasingly used in high rue building and it is very obvious re consider fire resistance performance of that. Unlike the normal strength concrete, high strength concrete in sudden elevating temperature at fire is susceptible to spalling with severe explosion and surface split, due to high density of concrete. In order to endure the spalling, inner space temperature of concrete should be control less than certain point. Therefore this study investigated the influence of covering materials on high strength concrete finishing spray-on materials of fiber composite spray mortar(FCSM). Both polypropylene(PP) and polyvinyl alcohol(PVA) fiber were used in this test. Test showed that concrete, covering 18mm mortar containing PVA fiber and confining metal lath 2.3mm thickness, decreased 50% of main bar ambient temperature. compared with control concrete. In addition, concrete covering 18mm mortar without fiber caused falling of covering materials and then it was exposed in elevating temperature. As a result, spatting of the concrete occurred same as control concrete. However, concrete covering spray-on mortar containing PVA or PP fiber resisted spatting occurrence.

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A STUDY ON THE BOND STRENGTH OF REPAIRED GLASS IONOMER CEMENTS (Repaired glass ionomer cement의 결합강도에 관한 연구)

  • Seo, Su-Jeong;Kim, Shin
    • Journal of the korean academy of Pediatric Dentistry
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    • v.23 no.2
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    • pp.347-355
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    • 1996
  • The purpose of this study was to compare the bond strengths of different kinds of glass ionomer cements (GIC), which is recently increasing the clinical application in the field of pediatric dentistry and measure the repaired bond strengths in order to examine the clinical applicabilty of partial repaired cases. By using one kind of the light cured type GIC and three kinds of the chemical cured type GIC, the bond strengths of the followings were compared : unrepaired group as control, repaired conditioning group, which was treated the repaired surface using 25% polyacrylic acid and repaired non-conditioning group without surface treatment. Three point bending test was performed under Universal Testing Machine in order to measure the compressive bond strengths. The results were as follows : 1. Light cured GIC had higher bond strength than chemical cured type GIC in both of repaired and unrepaired groups. 2. In repaired cases, all of the materials decreased the bond strength when compared to the control group. In the light cured type, the bond strength of repaired conditioning group decreased 31.6%, repaired non-conditioning group decreased 40.8%. In chemical cured types, the bond strength of repaired conditining group decreased 11.8%, repaired non-conditioning group decreased 20.9%. 3. All the materials, in the case of the chemical treatment on the repaired surface using 25% polyacrylic acid had higher bond strength than untreated but, lower than control group.

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Effects of the kinesio taping with backward gait training on muscle strength of lower extremity and gait ability in post stroke patients (키네시오 테이핑을 병행한 후방보행훈련이 만성 뇌졸중 환자의 하지 근력 및 보행에 미치는 영향)

  • Kim, Kyung Hun
    • Journal of Korean Physical Therapy Science
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    • v.28 no.2
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    • pp.10-18
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    • 2021
  • Purpose: The objective of the present study was to examine the effects of Kinesio taping with backward walking training (KTBW) on muscle strength of lower extremity and gait ability in post-stroke patients. Design: Randomized controlled trial. Method: Participants included 27 post stroke patients and were randomly distributed into two groups: KTBW group received Kinesio taping with backward training (n=13), control group receive general physical therapy (n=14). Intervention was given five times a week, a total of four weeks. The subjects evaluated the muscle strength test and walking ability before and 4 weeks after the experiment. Muslce strength of lower extremity was measured by digital manual muscle test. Gait ability was measured by G-walk. Result: After training, the KTBW group showed significant improvement in muscle strength of the lower extremity compared to the control group (p<0.05). KTBW group showed significant improvement in gait ability compared to the control group (p<0.05). Conclusion: These finding show the benefits of the Kinesio taping with backward walking training on the muscle strength of lower extremity and gait ability in post stroke patients.

Relationship between the Maximal Tongue and Lip Strength and Percentage of Correct Consonants and Speech Intelligibility in Dysarthric Adults with Cerebral Palsy (뇌성마비로 인한 마비말장애 성인의 최대 혀 및 입술 강도와 자음정확도 및 말명료도의 관계)

  • Choi, Yoejin;Sim, Hyunsub
    • Phonetics and Speech Sciences
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    • v.5 no.2
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    • pp.11-22
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    • 2013
  • The purpose of this study was to identify the relationship between the strength of the tongue/lip strength and speech production for dysarthric adults with cerebral palsy. The maximal tongue and lip strengths of 22 normal adults, 27 dysarthric adults (10 adults with mild dysarthria, 10 adults with moderate dysarthria, and 7 adults with severe dysarthria) were measured with Iowa Oral Performance Instrument (IOPI). The percentage of correct consonants (PCC) and speech intelligibility were calculated from the words and sentences spoken by the subjects. The results of the study are as follows: First, both the maximal tongue and the maximal lip strength differed significantly between the control group and the group with dysarthria. While the group with mild dysarthria did not show meaningful difference in maximal tongue and lip strengths from the control group, the group with moderate and severe dysarthria showed significantly weaker tongue and lip strength than the control group and the group with mild dysarthria. Second, the current study suggests the existence of a significant correlation between the maximal tongue and lip strength and the PCC and speech intelligibility within all subjects with dysarthria. These findings can serve as an effective foundation to diagnose dysarthria quickly and accurately. The results of this study also indicate that in addition to the maximal tongue strength, the maximal lip strength can prove to be an important index in predicting the speech intelligibility of dysarthric adults with cerebral palsy.

Influence of Aggregate on the Rebound Value of P Type Schmidt Hammer (P형 슈미트햄머의 반발도에 미치는 골재종류의 영향)

  • 김태현;김기정;이용성;이백수;윤기원;한천구
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.10a
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    • pp.239-242
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    • 2002
  • This study is intended to investigate the relationship between rebound value of P type schmidt hammer and the compressive strength with various aggregates, and a series of experiments about early strength quality control by P type schmidt hammer was performed. According to the results, the compressive strength of concrete using basalt and limestone aggregate is higher by 3% and lower by 4% than that of concrete using granite aggregate respectively. Concrete using basalt and lime stone aggregate show high rebound value in vertical strike. Estimation of the compressive strength does not show differences in horizontal strike, but the compressive strength is estimated high in order of granite, basalt and limestone aggregate in vertical strike. A good correlation between the rebound value of schmidt hammer and the compressive strength is confirmed regardless of aggregate types, so it could be possible to control the quality of concrete by P type schmidt hammer test when basalt and limestone aggregates are used at the same time.

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A Study on Early Strength Estimation of Precast Concrete joint Mortar with Microwave (마이크로파에 의한 PC접합모르타르의 조기강도추정에 관한 연구)

  • 원준연;박일용;백민수;이종균;안형준;정상진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.217-222
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    • 2000
  • A large Pc structure building is system that consisted of bearing wall and slab joint. It has general structure stability from unity thar each members tied at joint. The strength of mortar that packing in joint among panels is important to internal force in entire building system. Do, if we could get early strength estimation with microwave. It would bring good construction planning, reduce construction time, and judge building stability and so on. The purpose of this study is to develop early estimation method for making better quality control and constructing good PC panel structure. The results of this study were as follows :1) With sealed molds, reduced moisture volatilization to more than 60% and enlarged 30% accelerated compressive strength than before one. 2) To get more accelerated strength, we should control maximum temperature difference to $30^{\circ}C$ downward 3)Interrelation with 7-day and 28-day strength were 0.831,0.902, and it is above than before one

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Fracture Behavior of Reinforced Concrete Beams Repaired by Latex-Modified Concrete (LMC로 보강된 철근콘크리트 보의 파괴거동)

  • 김성환;정원경;김기헌;김동호;윤경구
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.475-480
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    • 2003
  • Latex modification of concrete provides the material with higher flexural strength. This increase in flexural strength can attribute to the crack-arresting action of polymer in concrete, and also to the bonding they provide between the matrix and aggregates. This experimental study presents the fracture behavior of 12 flexural reinforced concrete beams repaired or strengthened by latex-modified concrete with the main experimental variables such as overlay thickness, strength thickness, and shear reinforcement. The results are as follow: All beam specimens having shear reinforcement were failed by delamination rupture at concrete interface at about 80% of ultimate loading after flexural cracking. All specimens overlayed and strengthened by latex-modified concrete (LMC) showed higher ultimate flexural strength than OPC control specimen, but lower than LMC control specimen. This increase in flexural strength could attribute to the high bonding they provide between the matrix and aggregates. All specimens except two shear unreinforced showed quite similar and consistent displacement behavior. The effect of overlay and strength thickness on the load-displacement relationship were a small at this study.

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