• Title, Summary, Keyword: tensile force

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Development of Visual Confirmation Device for Anchor Tensile Force (앵커 긴장력 상시확인을 위한 육안확인장치 개발)

  • Yoon, Hwan Hee;Lee, Yong Joo;Oh, Dong Wook;Kim, Dong Hyun;Jung, Hyuk Sang
    • Tunnel and Underground Space
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    • v.28 no.5
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    • pp.493-511
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    • 2018
  • This paper deals with visual confirmation device for tensile force verification in order to cope with tensile force loss of ground anchor. Ground anchors are constructed to ensure the stability of social infrastructure facilities, but continuous loss of tensile force is seriously concerned about safety of the facilities. This requires the maintenance of the anchors, but the current measuring of residual tensile force is done by sampling, taking into account economic aspects, which limits precision. In this paper, conducted a conceptual design, tensile experiment, and field test for the purpose of developing an anchor tensile force visual device to check the tensile force of the anchors.

A new analytical approach to estimate the seismic tensile force of geosynthetic reinforcement respect to the uniform surcharge of slopes

  • Motlagh, Ali Tafreshi;Ghanbari, Ali;Maedeh, Pouyan Abbasi;Wu, Wei
    • Earthquakes and Structures
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    • v.15 no.6
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    • pp.687-699
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    • 2018
  • This paper investigates the pseudo-static analysis of reinforced slopes with geosynthetics under the influence of the uniform surcharge to evaluate the maximum tensile force of reinforcements. The analytical approach has basically been used to develop the new practical procedure to estimate both tensile force and its distribution in the height of the slope. The base of developed relationships has been adapted from the conventional horizontal slice method. The limit equilibrium framework and the assumptions of log-spiral failure surface have directly been used for proposed analytical approach. A new analytical approach considering a single layer of non-cohesion soil and the influence of uniform surcharge has been extracted from the 5n equation and 5n unknown parameters. Results of the proposed method illustrated that the location of the surcharge, amount of internal friction and the seismic coefficient have the remarkable effect on the tensile force of reinforcement and might be 2 times increasing on it. Furthermore, outcomes show that the amount of tensile force has directly until 2 times related to the amount of slope angle and its height range. Likewise, it is observed that the highest value of the tensile force in case of slope degree more than 60-degree is observed on the lower layers. While in case of less degree the highest amount of tensile force has been reported on the middle layers and extremely depended to the seismic coefficient. Hence, it has been shown that the tensile force has increased more than 6 times compared with the static condition. The obtained results of the developed procedure were compared with the outcomes of the previous research. A good agreement has been illustrated between the amount results of developed relationships and outcomes of previous research. Maximum 20 and 25 percent difference have been reported in cases of static and seismic condition respectively.

THE EFFECT OF TENSILE FORCE ON DNA AND PROTEIN SYNTHESIS IN BONE CELLS (인장력이 골조직 세포군의 DNA 및 단백합성에 미치는 영향)

  • Kwon, Oh-Sun;Kim, Sang-Cheol
    • The korean journal of orthodontics
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    • v.24 no.4
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    • pp.933-943
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    • 1994
  • The present study was undertaken to determine the effect of tensile force on DNA and protein biosynthesis in bone cells, and to identify the cell type(s) which primarily respond to external physical force among the heterogenous bone cell populations. As a prerequisite for this study, two bone cell populations which retain fibroblastic and osteoblastic feature were isolated from fetal rat calvaria with sequential enzyme digestion scheme. Tensile force was delivered to each bone cell population by two acrylic resin plates connected with a orthodontic expansion screw during culture period. Rate of DNA and protein synthesis in each bone cell population were assessed by the incorporated radioactivity of $[^3H]-thymidine$ into DNA and $[^3H]-proline$ into fraction of collagenase-digestible protein and noncollagenous protein, respectively. DNA synthesis of osteoblast-like calvarial cell populations was increased significantly by the application of tensile force for 24 hours. In contrast, no alteration in DNA synthesis of fibroblast-like populations could be observed in response to applied force. Tensile force induced the change in protein synthesis of bone cell populations with the same pattern. Total protein and collagen synthesis were increased whithin 24 hours in osteoblast-like populations, but not in fibroblast-like populations by tensile force application. These findings indicate that physical force can affect cellullar activity of the particular cell population, not all cell Populations residing in bone and osteoblasts respond more sensitively than fibroblasts. So osteoblasts can modulate the behavior of other bone cells including osteoclasts by producing several local regulating factors of bone metabolism. In this context, preferential responsiveness of osteoblasts to applied tensile force observed in this study suggests that osteoblasts may play an important role in regulation of physical force-induced remodelling process.

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Development of a Tensile Force Measurement Device for Long-term (인장력 장기 측정기 개발에 관한 연구)

  • Shin, Kyung Jae;Lee, Swoo Heon
    • Journal of Korean Society of Steel Construction
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    • v.18 no.6
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    • pp.759-768
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    • 2006
  • The turn-buckle inserted between tension members is a device adjusting a tensile force in tension member. However, the measurement of designed tensile force is impossible and the tensile force is determined based on the experience of field workers. The conventional turn-buckle might be used without any adjustment even though the tensile force has been changed for long term. To improve the disadvantages of conventional turn-buckles a turn-buckle which is measurable the tensile force is developed. In this study, the displacement to the lateral direction is induced by the deformation of curved elements if the tensile force is applied to the new type of turn-buckle that the straight elements are slightly curved. The total lateral displacement could be measured by using the micrometer or vernier-calipers. Trial devices for a measurable turn-buckle were made and tested. An theoretical study was also conducted to show the applicability, and parametric studies were conducted. The appropriate shape and capacity were determined by the parametric study.

Characteristics of Barkhausen Noise Properties and Hysteresis Loop on Tensile Stressed Rolled Steels

  • Kikuchi, Hiroaki;Ara, Katsuyuki;Kamada, Yasuhiro;Kobayashi, Satoru
    • Journal of Magnetics
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    • v.16 no.4
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    • pp.427-430
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    • 2011
  • The rolled steels for welded structure applied tensile stress have been examined by means of magnetic Barkhausen noise (MBN) method and of a physical parameter obtained from a hysteresis loop. The behaviors of MBN parameters and coercive force with tensile stress were discussed in relation to microstructure changes. There is no change in MBN parameters and coercive force below yield strength. The coercive force rises rapidly with tensile stress above yield strength. On the other hand, the rms voltage and the peak in averaged rms voltage take a maximum around yield strength and then decreases. The magnetomotive force at peak in the averaged rms voltage shows a minimum around yield strength. These phenomena are attributed to the combined effects of cell texture and dislocation density. In addition, the behaviors of MBN parameters around yield strength may be reflected by the localized changes in strain field due to the formation of dislocation tangles.

Estimation of a tensile force in a cable using dynamic characteristics (진동특성을 이용한 케이블의 인장력 산정)

  • Choi, Sang-Hyun;Nam, Dong-Ho
    • Proceedings of the KSR Conference
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    • pp.461-467
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    • 2007
  • Exact application of the tensile force is critical to high-tension members in civil engineering structures, and thus actual tensile forces have often been estimated in field. To date, a few methodologies have been presented utilizing static and/or dynamic responses of tension members. Each of these methods has its disadvantages as well as advantages in its procedures, accuracy, and equipment requirements. In this paper, the feasibility of a sensitivity based methodology, based on the relationship between the natural frequencies and the applied tensile force, developed by the authors, is verified using the measured data from a cable-stayed bridge structure. From the results, it is shown that the proposed method can be utilized in estimating the tensile force in tension member of a real structure.

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An electromechanical impedance-based method for tensile force estimation and damage diagnosis of post-tensioning systems

  • Min, Jiyoung;Yun, Chung-Bang;Hong, Jung-Wuk
    • Smart Structures and Systems
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    • v.17 no.1
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    • pp.107-122
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    • 2016
  • We propose an effective methodology using electromechanical impedance characteristics for estimating the remaining tensile force of tendons and simultaneously detecting damages of the anchorage blocks. Once one piezoelectric patch is attached on the anchor head and the other is bonded on the bearing plate, impedance responses are measured through these two patches under varying tensile force conditions. Then statistical indices are calculated from the impedances, and two types of relationship curves between the tensile force and the statistical index (TE Curve) and between statistical indices of two patches (SR Curve) are established. Those are considered as database for monitoring both the tendon and the anchorage system. If damage exists on the bearing plate, the statistical index of patch on the bearing plate would be out of bounds of the SR curve and damage can be detected. A change in the statistical index by damage is calibrated with the SR curve, and the tensile force can be estimated with the corrected index and the TE Curve. For validation of the developed methodology, experimental studies are performed on the scaled model of an anchorage system that is simplified only with 3 solid wedges, a 3-hole anchor head, and a bearing plate. Then, the methodology is applied to a real scale anchorage system that has 19 strands, wedges, an anchor head, a bearing plate, and a steel duct. It is observed that the proposed scheme gives quite accurate estimation of the remaining tensile forces. Therefore, this methodology has great potential for practical use to evaluate the remaining tensile forces and damage status in the post-tensioned structural members.

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
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    • pp.1690-1692
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    • 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.

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Development of a Tensile Force Measurement Device of Long Duration (인장력 상시 측정장치 개발에 관한 연구)

  • Shin, Kyung Jae;Hwang, Yun Ha
    • Journal of Korean Society of Steel Construction
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    • v.15 no.4
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    • pp.435-445
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    • 2003
  • Tension member is one of the most important elements in tension structure. An economical and reliable measurement method of a member's tensile force has yet to be developed, however. Several conventional measurement methods have some disadvantages when used for long-term, on-site measurement. A new tension-force measurement device was proposed to resolve measuring problems. Its principle was to use the bending part of the device as an elastic spring. The lateral deformation of the bending part due to tensile force can be measured to monitor the tensile force. This device was inserted in the tension member like a turn-buckle. Lateral deformation may be measured in the field at any time for the purpose of maintaining structures. Finite element analysis was used to design the shape and parametric study. Six specimens were tested within the elastic range. The test result showed that the elastic behavior or the bending part was consistent with the analysis' results.

Comparison of CAD/CAM abutment and prefabricated abutment in Morse taper internal type implant after cyclic loading: Axial displacement, removal torque, and tensile removal force

  • Yi, Yuseung;Heo, Seong-Joo;Koak, Jai-Young;Kim, Seong-Kyun
    • The Journal of Advanced Prosthodontics
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    • v.11 no.6
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    • pp.305-312
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    • 2019
  • PURPOSE. The purpose of this study was to compare computer-aided design/computer-aided manufacturing (CAD/CAM) abutment and prefabricated abutment in Morse taper internal connection type implants after cyclic loading. MATERIALS AND METHODS. The study was conducted with internal type implants of two different manufacturers (Group Os, De). Fourteen assemblies were prepared for each manufacturer group and divided into 2 groups (n=7): prefabricated abutments (Os-P, De-P) and CAD/CAM abutments (Os-C, De-C). The amount of axial displacement and the removal torque values (RTVs) were measured before and after cyclic loading (106 cycles, 3 Hz with 150 N), and the tensile removal force to dislodge the abutments was measured after cyclic loading. A repeated measures ANOVA and a pattern analysis based on the logarithmic regression model were conducted to evaluate the effect of cyclic loading on the axial displacement. The Wilcoxon signed-rank test and the Mann-Whitney test was conducted for comparison of RTV reduction% and tensile removal forces. RESULTS. There was no significant difference between CAD/CAM abutments and prefabricated abutments in axial displacement and tensile removal force; however, significantly greater RTV reduction% after cyclic loading was observed in CAD/CAM abutments. The correlation among the axial displacement, the RTV, and the tensile removal force was not significant. CONCLUSION. The use of CAD/CAM abutment did not significantly affect the amount of axial displacement and tensile removal force, but presented a significantly greater removal torque reduction% than prefabricated abutments. The connection stability due to the friction at the abutment-implant interface of CAD/CAM abutments may not be different from prefabricated abutment.