• Title, Summary, Keyword: Compressive force

Search Result 546, Processing Time 0.037 seconds

System identification of steel member acting compressive force using natural frequency of vibration (고유진동수를 이용하여 압축력이 작용하는 철골 부재의 구조계 추정)

  • Shim, Hak-Bo;Park, Soo-Yong;Park, Hyo-Seon
    • 한국방재학회:학술대회논문집
    • /
    • /
    • pp.45-48
    • /
    • 2007
  • The aim of this study is to estimate the compressive force of steel member using a system identification technique with vibration measurements. To date, several methods have been presented to estimate the compressive force using static and/or dynamic responses of the steel member. However, each and every one of these methods has its disadvantages as well as advantages in its procedures, level of accuracy, and equipment requirements. The paper reports a qualitative investigation of vibration under monoharmonic excitation. The methodology utilizes the relationship between the natural frequencies, the structural parameters, and the compressive force of the member. In this paper, experimental results are presented with a steel beam subjecting to several compressive forces and the proposed method is validated using both numerical and experimental data.

  • PDF

A Pilot Study on Nondestructive Assessment of Compressive Strength Using Impact Force Response Signal (충격력 응답신호를 이용한 비파괴 압축강도 산정에 관한 기초연구)

  • Son, Moorak;Choi, Yoonseo
    • Journal of the Korean Geoenvironmental Society
    • /
    • v.20 no.4
    • /
    • pp.5-9
    • /
    • 2019
  • This paper is to provide the results of a pilot study of the usability and possibility of impact force response signal induced from impacting an object for the assessment of compressive strength of various materials (rock, concrete, wood, etc.) nondestructively. For this study, a device was devised for impacting an object and measuring the impact force. The impact was carried out by an initial rotating free falling impact and following repetitive impacts from the rebound action which eventually disappears. Wood and rock test specimens for different strengths were tested and an impact force response signal was measured for each test specimen. The total impact force signal energy which is assessed from integrating the impact force response signal was compared with the directly measured compressive strength for each specimen. The comparison showed that the total impact force signal energy has a direct relationship with the directly measured compressive strength and the results clearly indicated that the compressive strength of construction materials can be assessed nondestructively using total impact force signal energy which is assessed from integrating the impact force response signal induced from impacting an object.

A variation of tensile force with the terminal height (단자(Terminal) 압착고에 따른 인장력 변화에 대한 고찰)

  • Shin, Young-Lok;Yang, Yun-Suk;Kim, Chul-Han;SaGong, Geon
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.1690-1692
    • /
    • 2000
  • The principle of crimping connection is to produce a compressive connection force between terminal and cores(wire conductor). Compressive connection force is produced by pushing each other on that stress(crimping force) of barrel by restored elastic strain after plastic deformation and the expansion force of cores' elastic stress. And resistance and tension force between terminal and cores are determined according to the condition of compressive connection force. In this study, we've found out that the adaptive height which has maximum tensile force by measuring a tensile force with a height of terminal.

  • PDF

The Differences in Patellofemoral Compression Force with Different Height (드롭랜딩 시 높이에 따른 슬개대퇴 압박력의 차이)

  • Cho, Joon-Haeng;Kim, Kyoung-Hun;Moon, Gon-Sung;Lee, Sung-Cheol
    • Korean Journal of Sport Biomechanics
    • /
    • v.21 no.3
    • /
    • pp.335-343
    • /
    • 2011
  • Patellofemoral pain syndrome is the most common problem involving the knee, accounting for 25% of knee injuries. Repetitive, overuse activities cause increased force at the patellofemoral joint, resulting in pain during flexion and extension activities. Most research have been conducted in exploring the patellofemoral compressive force in gait, squat and lunges, even though in real cases, possibilities in landing exist. The purpose of this study was to compare the differences in patellofemoral compressive force according to two different height. Sixteen collegiate male students(age: 22.25 ${\pm}$ 3.30 yrs, height: 177.25 ${\pm}$ 4.44 cm, weight: 77.50 ${\pm}$ 8.18 kg) were chosen. The subjects performed drop landings in 45 cm, 60 cm. The findings demonstrated that higher height showed peak knee extension moment, quadriceps contraction force, patellofemoral compressive force with increased VGRF. Regarding the patellofemoral joint compressive force, it increased by quadriceps contraction force with knee flexion during landing, yet, it showed no difference in maximal knee flexion. To minimize patellofemoral joint stress and reduce the likelihood of developing PFPS, we recommend that predesigned quadriceps and hip muscle group strengthening are needed during conditioning and training.

Finite Element Analysis of Residual Stress by Cold Expansion Method with Clamping Force in the Plate having Adjacent Holes (인접홀에서 홀확장법과 체결력 고려시, 발생하는 잔류응력 분포에 대한 유한요소해석)

  • Yang Won-Ho;Cho Myoung-Rae;Jang Jae-Soon
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.23 no.5
    • /
    • pp.149-154
    • /
    • 2006
  • The cold expansion method (CEM) is one of the widely used a method to improve the fatigue behavior of materials in aerospace industry. Such improvement is due to the compressive residual stress developed when a tapered mandrel goes through the fastener holes a little smaller than the mandrel. CEM is retarded of crack initiation due to the compressive residual stress developed on the hole surface. Many researchers are studied a finite element analysis of residual stress around fastener hole. But in case of real model, fastener hole has a clamping force after CE. Therefore, it is respected that residual stress distributions should be changed due to clamping forces. In this paper, it was performed finite element analysis of residual stress by clamping force after CE in the plate having adjacent holes. From this study, it has been found that compressive residual stress near the hole increases according to clamping force. Also, the more increase clamping force, the more increases compressive residual stress. However, tensile residual stress increase beyond clamping force area.

Application of the compressive-force path concept in the design of reinforced concrete indeterminate structures: A pilot study

  • Seraj, Salek M.;Kotsovos, Michael D.;Pavlovic, Milija N.
    • Structural Engineering and Mechanics
    • /
    • v.3 no.5
    • /
    • pp.475-495
    • /
    • 1995
  • In the past, physical models have been proposed, in compliance with the concept of the compressive-force path, for the realistic design of various statically determinate structural concrete members. The present work extends these models so as to encompass indeterminate RC structural forms. Pilot tests conducted on continuous beams and fixed-ended portal frames have revealed that designing such members to present-day concepts may lead to brittle types of failure. On the other hand, similar members designed on the basis of the proposed physical models attained very ductile failures. It appears that, unlike current design approaches, the compressive-force path concept is capable of identifying those areas where failure is most likely to be triggered, and ensures better load redistribution, thus improving ductility. The beneficial effect of proper detailing at the point of contraflexure in an indeterminate RC member is to be noted.

A FEM ANALYSIS FOR INITIAL STRESS ON THE UPPER GAMINE BY ORTHODONTIC FORCE OF INTRUSION ARCH WIRE ACTIVATION (Intrusion arch wire activation시 상악 견치에 가해진 초기응력의 유한요소법을 통한 고찰)

  • Kang, Jeong-Weon;Cha, Kyung-Suk;Lee, Jin-Woo
    • The korean journal of orthodontics
    • /
    • v.28 no.3
    • /
    • pp.391-398
    • /
    • 1998
  • The purpose of this study was to find the distribution and measurement of compressive and tensile stress when intrusi- on arch wire is forced engage with upper canine and to analysis stress at each section through FEM. And we compare compressive and tensile ratio at each section. The results were as follows. 1. At FA point and cemento-enamel junction of upper canine, compressive and tensile force ratio is about the same. 2. At apex, compressive force is the four times as tensile force. ; In intrusion, we show root resorption at apex. 3. At Cemento-enamel junction, the compressive and tensile force show the maximun value except FA Point.

  • PDF

Prediction of Peak Back Compressive Forces as a Function of Lifting Speed and Compressive Forces at Lift Origin and Destination - A Pilot Study

  • Greenland, Kasey O.;Merryweather, Andrew S.;Bloswick, Donald S.
    • Safety and Health at Work
    • /
    • v.2 no.3
    • /
    • pp.236-242
    • /
    • 2011
  • Objectives: To determine the feasibility of predicting static and dynamic peak back-compressive forces based on (1) static back compressive force values at the lift origin and destination and (2) lifting speed. Methods: Ten male subjects performed symmetric mid-sagittal floor-to-shoulder, floor-to-waist, and waist-to-shoulder lifts at three different speeds (slow, medium, and fast), and with two different loads (light and heavy). Two-dimensional kinematics and kinetics were captured. Linear regression analyses were used to develop prediction equations, the amount of predictability, and significance for static and dynamic peak back-compressive forces based on a static origin and destination average (SODA) backcompressive force. Results: Static and dynamic peak back-compressive forces were highly predicted by the SODA, with R2 values ranging from 0.830 to 0.947. Slopes were significantly different between slow and fast lifting speeds (p < 0.05) for the dynamic peak prediction equations. The slope of the regression line for static prediction was significantly greater than one with a significant positive intercept value. Conclusion: SODA under-predict both static and dynamic peak back-compressive force values. Peak values are highly predictable and could be readily determined using back-compressive force assessments at the origin and destination of a lifting task. This could be valuable for enhancing job design and analysis in the workplace and for large-scale studies where a full analysis of each lifting task is not feasible.

종이의 단축압축 표준시험법 개발

  • Kim, Hyoung-Jin;Um, Gi-Jeung;Lee, Tai-Ju;Ko, Seung-Tae;Yoo, Yeong-Jeong
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
    • /
    • /
    • pp.325-330
    • /
    • 2007
  • Uniaxial tensile test are generally much simpler than uniaxial compressive test. Uniaxial compressive test is experimentally more difficult because of the low buckling resistance of a sheet of paper. In order to avoid buckling, many researchers have applied various lateral restraint techniques to investigate paper uniaxial compression behavior. Adding unnecessary force to inhibit compressive deformation of the sheet is unwanted, but sufficient force must be used to inhibit buckling. This study has been carried out to develop new uniaxial compressive standard test method without exerting unnecessary force to paper specimen to prevent buckling.

  • PDF

Impact of Lumen Size and Helical Coil Place Change in Spring on Orthodontic Force (Spring의 lumen size와 helical coil 형성 위치 변화가 교정력에 미치는 영향)

  • Lee, Gyu-Sun;Lee, Sun-Kyoung;Kim, Bok-Dong
    • The Journal of Korean Academy of Dental Technology
    • /
    • v.33 no.4
    • /
    • pp.331-337
    • /
    • 2011
  • Purpose: The purpose of this study was to impact of force system change in finger spring that add helical coil one round on orthodontic force. Methods: The following conclusions were drawn from the experiment conducted after bending 90 samples with a CNC wire forming machine while changing the height and lumen size to 1mm - 3mm - 5mm and 2mm - 3mm - 4mm respectively in the coil of the force system in finger spring added with one wheel of helical coil of 18-8 stainless steel round wire (${\Phi}0.5mm$, spring hard) from Jinsung Co. in domestic market under the following conditions: Laboratory name = Instron 5942; Temperature($deg^{\circ}C$) = 18.00; Humidity(%) = 50.00; Rate 1 = 10.00000 mm/min; Compressive extension = 5.0mm. Results: When Coil height is 1, 3, 5mm and lumen size is 2, 3, 4mm reduce finger spring as mean value of compressive extension occasion maximum load(mN) increases as coil height rises, and lumen size grows to 5.0mm. And was expose that compressive load(mN) increases as coil position of finger spring rises and increase as lumen size is decrescent. Conclusion: As the adherence height of coil was raised from 1mm through 3mm to 5mm, compressive load increased. As the lumen size increased from 2mm through 3mm to 4mm, compressive load decreased. Therefore, these results suggest that it is desirable to lower the coil height and enlarge the lumen size to enhance the biomechanical efficiency of finger spring when manufacturing the finger spring for removable orthodontic devices.