• Title/Summary/Keyword: Joint Strengths

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Estimation of anthropometric body dimensions and joint strengths of a worker performing manual materials handling tasks using a multivariate normal simulation model (다변량 정규분포 모의모형을 이용한 물자운반작업을 수행하는 작업자의 인체 치수 및 관절염력의 예측에 관한 연구)

  • 변승남
    • Journal of the Ergonomics Society of Korea
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    • v.12 no.2
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    • pp.63-83
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    • 1993
  • The primary objective of the research is to develop a mathematical method to incorporate the variability of anthropometric body dimensions and joint strengths of individuals in a biomechanical analysis. A multivariate normal simulation model estimated anthropometric body dimensions and joint strengths of the random link-person, based on the assumptions that the vari- ables of body dimensions and joint strengths are correlated and follow normal distributions. Statistical comparative analysis demonstrated that the random link-person represented a more realistic human-like form in an anthropometric sense than the proportional link-person whose body dimensions were estimated proportionally. Estimated joint strengths for the random link-person, however, did not match the measured joint strengths as closely as the estimated body dimensions. The random link-person will allow biomechanical analysis of manual materials handling tasks to be individualized with respect to the anthropometry and a static strength.

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A STUDY REPAIRED JOINT STRENGTH OF COMPLETE DENTURE (의치수리(義齒修理)에 있어 파절접합부(破折接合部)의 조작형태(造作形態)가 의치(義齒)의 결합력(結合力)에 미치는 영향(影響)에 관(關)한 연구(硏究))

  • Lee Woo-Hyun;Heo Seong-Joo;Cho In-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • v.29 no.3
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    • pp.101-110
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    • 1991
  • The purpose of this study was to compare the repaired joint strength among several edge profiles after denture repair. For this study, eight edge profiles were used for repair methods and five self-curing resin brands were used for repair materials. Break away loads were tested after 1 hr., 24 hrs. and 1 week. Instron was used for testing the transverse strength of repaired specimen. The results were as follows. 1. Repaired joint strength was about 35-65% of that of original specimen. 2. Joint strengths of round, inverse knife, inverse rabbit, lap ogee joint were higher tnan that of traditional simple butt joint 3. Joint strength of the simple butt joint was low significant. 4. Joint strengths after 1 hr. specimen were lower than those of 24 hrs. and 1 week specimens in joint strengths. 5. There were no significant differences between 24 hrs. and 1 week specimens in joint strengths. 6. It look more than 24 hours to gain satisfactory physical property after repairing the fractured denture base when self-curing resin was used for repair.

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Interaction of internal forces of interior beam-column joints of reinforced concrete frames under seismic action

  • Zhou, Hua;Zhang, Jiangli
    • Structural Engineering and Mechanics
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    • v.52 no.2
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    • pp.427-443
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    • 2014
  • This paper presents detailed analysis of the internal forces of interior beam-column joints of reinforced concrete (RC) frames under seismic action, identifies critical joint sections, proposes consistent definitions of average joint shear stress and average joint shear strain, derives formulas for calculating average joint shear and joint torque, and reports simplified analysis of the effects of joint shear and torque on the flexural strengths of critical joint sections. Numerical results of internal joint forces and flexural strengths of critical joint sections are presented for a pair of concentric and eccentric interior connections extracted from a seismically designed RC frame. The results indicate that effects of joint shear and torque may reduce the column-to-beam flexural strength ratios to below unity and lead to "joint-yielding mechanism" for seismically designed interior connections. The information presented in this paper aims to provide some new insight into the seismic behavior of interior beam-column joints and form a preliminary basis for analyzing the complicated interaction of internal joint forces.

New Joint Roughness Coefficient and Shear Strength Criterion Based on Experimental Verification of Standard Roughness Profile (표준 거칠기 단면의 실험적 검증에 의한 새로운 거칠기 계수 및 전단강도 기준식)

  • Jang, Hyun-Sic;Sim, Min-Yong;Jang, Bo-An
    • The Journal of Engineering Geology
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    • v.31 no.4
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    • pp.561-577
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    • 2021
  • The ten standard roughness profiles suggested by Barton and Choubey (1977) were extended to make three-dimensional (3D) joint models whose profiles were identical at any cross section. Replicas of joint models were produced using plaster of Paris, and direct shear tests were performed to verify the joint roughness coefficients (JRC) of the standard roughness profiles. Joint shear strengths measured by direct shear tests were compared with those predicted by the shear failure criterion suggested by Barton (1973) based on JRC, joint compressive strength (JCS), and joint basic friction angle (𝜙b). Shear strengths measured from joints of the first and fourth standard roughness profiles were close to predicted values; however, shear strengths measured from the other joint models were lower than predicted, the differences increasing as the roughness of joints increased. Back calculated values for JRC, JCS, and from the results of the direct shear tests show measured shear strengths were lower than predicted shear strengths because of the JRC values. New JRC were back calculated from the measured shear strength and named JRCm. Values of JRCm were lower than the JRC for the standard roughness profiles but show a strong linear relationship to JRC. Corrected JRCm values for the standard roughness profiles are provided and revised relationships between JRCm and JRC, and new shear strength criterion are suggested.

Muscle Strength Measurement using Shoulder and Upper Joint for Korean Young-aged (우리나라 청년층의 어깨 및 상지관절을 이용한 근력 측정)

  • Yoon, Hoon-Yong;Kim, Eun-Sik
    • Journal of the Ergonomics Society of Korea
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    • v.28 no.3
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    • pp.125-134
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    • 2009
  • The muscle strengths in various postures are used in our daily life with or without our recognition. Also, many works are still performed with strengths, although mechanization and automation have been fairly accomplished at the industry site. Since the late seventies, various body measurements have been conducted periodically in Korea, however, muscle strengths have not been measured actively. For this reason, the muscle strength data have been hardly accumulated. The aims of this study are to learn more about the physical strength of young-aged Koreans and to provide basic information for designing equipments, tools and facilities in the work site and daily life. The muscle strengths that are related to shoulder and upper limbs joints, which are used frequently, are measured in this study. Eighteen muscle strengths, from seven different movements such as elbow flexion, elbow extension, shoulder abduction(seated), shoulder adduction(seated), shoulder rotation(internal and external), lifting a tray, and turning a key(inward and outward) were measured. For every movement, the muscle strengths for both hands were measured. In each measurement, five seconds averaged value and peak value were collected. Comparing the average value, the strength of shoulder adduction was the strongest for male and female, while strength of turning a key inward with left hand was the weakest for male and female. Strengths of preferred hand in elbow extension, shoulder abduction, shoulder external rotation, lifting a tray, and turning a key were stronger than those of non-preferred hand for both male and female. Rohrer's index considerably had an effect on muscle strength. The results of this study can provide some basic information not only in designing the equipment and facilities in work site or daily life, but also in selection, training and management of workers.

An Experimental Study on the Tensile and Fatigue Strengths of SUS304L Lap Joint Weld at the Cryogenic Temperature (SUS304L 겹침 용접부에 대한 극저온에서의 인장 및 피로강도에 관한 실험적 연구)

  • Kim, Kyung-Su;Boo, Seung-Hwan;Park, Chang-Youl;Cho, Young-Gun;Lee, Jeung-Soo
    • Journal of Ocean Engineering and Technology
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    • v.22 no.3
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    • pp.96-102
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    • 2008
  • As LNG tank is operated around $-162^{\circ}C$, an experimental approach on the cryogenic temperature tensile and fatigue strengths of SUS304L lap joint weld is very important at the design stage of membrane type LNG tank. In this study, in order to estimate the tensile and fatigue strengths of SUS304L lap joint weld at cryogenic temperature condition, tensile and fatigue tests were conducted. Also, S-N curves are presented with statistical testing method recommended by JSME. As a result of the experimental approach, the d£sign guide of fatigue strength is proposed and that is expected to be useful for membrane type LNG tank design.

Strength of Composit Single-lap Bonded Joints with Different Saltwater Moisture Contents (서로 다른 수분율을 갖도록 염수환경에 노출된 복합재 접착체결부의 강도)

  • Yang, Hyeon-Jeong;Jeong, Mun-Gyu;Kweon, Jin-Hwe;Choi, Jin-Ho
    • Composites Research
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    • v.24 no.4
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    • pp.48-54
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    • 2011
  • The effect of moisture contents by salt water on the strength of composite single-lap bonded joints is investigated. The specimens were manufactured in an autoclave by secondary bonding and immersed in the 3.5% salt water of $71^{\circ}C$ for different durations to get various moisture contents; 0, 0.2, 0.5, 1.0, and 2.0%(saturation). A total of 80 joint specimens were tested for 5 different moisture contents and 2 temperature environments. Test results show that while the joint strengths after the saturation of moisture decrease compared to those of dry ones, the strengths of the pre-saturated joint up to 1.0% of moisture content increase in both room and elevated temperature conditions. It is also shown that the strengths of joints tested in elevated temperature are slightly higher than the strength in room temperature by 2-5% until the moisture content reaches 1 %. In contrast, the high temperature strength of the saturated joint is about 5% lower than the room temperature strength.

The Effects of Pulsator Washing Machine on Joints Torques and Muscles Strengths Considering Height of Outside Machine and Depth of Inside Drum for Average Height Users (투입구 높이 및 내부 드럼 깊이를 고려한 펄세이터 세탁기 사용시 평균신장 사용자의 관절 토크 및 근력에 미치는 영향)

  • Kim, Seong Guk;Cho, Young Kuen;Lee, Nam Gi;You, Joshua Sung Hyun;Lim, Dohyung;Kim, Han Sung;Ko, Chang-Yong
    • Journal of Biomedical Engineering Research
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    • v.33 no.4
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    • pp.184-193
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    • 2012
  • Many studies have reported that housework done using household appliances may affect biomechanical characteristics of the musculoskeletal system. The purpose of this study was to investigate the effects of housework done using a pulsator washing machine on joints and muscles. We calculated joint torques and muscle strengths on the basis of an experimental/virtual three-dimensional motion analysis for six healthy females using the pulsator washing machine at different heights (H) and depths (D) of the inside drum (H (mm){\times}D (mm), Trial1: $962.5{\times}609.4$, Trial2: $962.5{\times}624.4$, Trial3: $982.5{\times}644.4$, Trial4: $995.5{\times}642.4$, Trial5: $1015.5{\times}677.4$). The joint torques and muscle strengths tended to be considerably different during torso flexion in the sagittal plane for all the trials. The maximum joint torques for the thoracic vertebra, left ankle, and right shoulder measured in Trial4 were significantly higher than those measured in the other trials (p < 0.05); in addition, those for the thoracic vertebra and both ankles measured in Trial5 were significantly higher than those measured in the other trials (p < 0.05). The maximum muscle strengths for the left trapezius muscle and both tibialis anterior muscles measured in Trial5 were significantly higher than those measured in the other trials (p < 0.05). These results indicate that housework done using a pulsator washing machine may affect joint torques and muscle strengths, and these effects are dependent on the height and/or depth of the inside drum of the pulsator washing machine.

Suggestion of the New Criteria on the Shear Strength of Rock Joint (새로운 암석 절리면 전단강도식의 제안)

  • 김대영;이영남
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.295-302
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    • 2002
  • Shear strength of the rock joint is dependent on the roughness and the compressive strength of the joint surface, normal stress and etc. Roughness of the joint profile is described by JRC suggested by Barton and Choubey (1977). Choice of the JRC value is subjective. A number of studies have been carried out to quantify the JRC. Predicted shear strengths by Barton's Equation using the new quantification method of JRC suggested by Chun and Kim (2001) were compared results of shear tests and new criteria of shear strength which have a better accuracy to predict shear strength was suggested.

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Refined 3-D Stress Analysis of Composite Wavy-Lap Joint (복합재료 Wavy-Lap Joint의 3-D 상세 응력 해석)

  • Shin, Hun;Lee, Chang-Sung;Kim, Seung-Jo;Kim, Wi-Dae
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.05a
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    • pp.168-171
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    • 2001
  • Due to intrinsic load eccentricity, severe peel stress concentration occurs at both ends of the single-lap joint. To avoid load eccentricity as well as the singular tensile peel stress in the joint interface, composite wavy-lap joint is proposed. In this paper, refined 3-D stress analysis of wavy-lap joint is performed by finite element method using parallel mutifrontal solver. Analysis results show that the singular tensile peel stress concentration is totally avoided in wavy-lap joint, and that loads are more evenly transferred over the length of the joint. Therefore, the strength of wavy-lap joint is significantly higher than that of conventional single-lap joint. And it is believed that even higher strengths can be obtained by optimizing the new design configuration.

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