• Title, Summary, Keyword: torsion

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Kinematic Analysis of Torsion Beam Rear Suspension (토션빔 후륜 현가장치의 기구학적 특성 해석)

  • 강주석
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.146-153
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    • 2004
  • Torsion beam rear suspension has been widely adopted to the rear suspension of vehicle by reason of simple structure and cost competitiveness. Since the kinematic characteristics of torsion beam rear suspension are determined by elastic behavior of torsion beam, quasi-static analysis based on finite element modeling of torsion beam has been conducted to obtain the kinematic parameters of torsion beam rear suspension. In this paper, simple kinematic equations with rear geometric parameters are derived to predict the kinematic behavior of torsion beam rear suspension. The suspension design parameters such as roll center height, roll stiffness, roll steer and roll camber can be easily obtained with the kinematic equations. The suggested kinematic equations are validated from comparison with the test results and solution offered by ADAMS. The suspension design parameters varied with the position of torsion beam are discussed.

A study on the structural characteristics and roll behavior of suspension for the section profile of torsion beam (토션빔의 단면형상에 다른 현가계의 구조적 특성과 롤 거동에 관한 연구)

  • 이동찬;변준형
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.9
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    • pp.195-202
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    • 1999
  • The kinematic and complicance characteristics of torsion beam axle is structurally related to the location and section profile of torsion beam and the span from body mounting point to wheel center. This paper presents the effect of section properties in torsion beam on the structural characteristics and roll behavior of suspension. The structural characteristics is on the maximum stress on the welding area of torsion beam and the roll behavior is on roll steer and roll-camber of suspension which are important for controllability and stability in cornering. Four factors are used for the section design of torsion beam, which are thickness , midline length, are inner radius, and sector half angle . Through the structural and quasi-static analysis made for six torsion beam axle models, it can be noticed that roll steer and the structural durability of suspension are closely related to warping constant and shear center in section properties of torsion beam.

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High Rate of Gangrenous Adnexal Torsion: Dilemma of a Missing Silent Cancer

  • Sukkong, Kanchanok;Sananpanichkul, Panya;Teerakidpisan, Prasong;Bhamarapravatana, Kornkarn;Suwannarurk, Komsun
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.11
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    • pp.4981-4984
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    • 2016
  • Background: Adnexal torsion results in ischemia of structures distal to twisted pedicle and acute onset of pain is responsible for about 3% of all gynecologic emergencies. Ovarian torsion classically occurs in a pathological enlarged ovary, as with cancer, but diagnosis remains a challenge. Objective: Our purpose was to evaluate clinical risk factors predictive of torsion with gangrenous adnexa. Material and methods: A retrospective descriptive study and chart review of surgically proven ovarian torsion/adnexal torsion cases at the Obstetrics and Gynecology Department of Prapokklao Hospital, Chanthaburi, Thailand between January 2011 and December 2015 was conducted. Result: Seventy-eight cases were identified. Mean age at presentation was 35.5 years. The average maximum diameter of the ovarian tumors was 10.8 cm. The percentage of gangrenous ovarian cysts in this study was 46.2 (36/78). The precision to determine the pathological site by patient, physician and ultrasonography was 8.5, 24.2 and 83.3 percent, respectively with statistically significant variation. Conclusion: Ovarian/adnexal torsion remains a challenge condition especially in young nulliparous women. Sophisticated investigation does not guarantee ovary preservation. Combining clinical acumen, appropriate tests and detailed consideration may be the best practice at the present time.

STRONGLY COTORSION (TORSION-FREE) MODULES AND COTORSION PAIRS

  • Yan, Hangyu
    • Bulletin of the Korean Mathematical Society
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    • v.47 no.5
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    • pp.1041-1052
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    • 2010
  • In this paper, strongly cotorsion (torsion-free) modules are studied and strongly cotorsion (torsion-free) dimension is introduced. It is shown that every module has a special $\mathcal{SC}_n$-preenvelope and an ST $\mathcal{F}_n$-cover for any $n\;{\in}\;\mathbb{N}$ based on some results of cotorsion pairs from [9]. Some characterizations of strongly cotorsion (torsion-free) dimension of a module are given.

REIDEMEISTER TORSION AND ORIENTABLE PUNCTURED SURFACES

  • Dirican, Esma;Sozen, Yasar
    • Journal of the Korean Mathematical Society
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    • v.55 no.4
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    • pp.1005-1018
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    • 2018
  • Let ${\Sigma}_{g,n,b}$ denote the orientable surface obtained from the closed orientable surface ${\Sigma}_g$ of genus $g{\geq}2$ by deleting the interior of $n{\geq}1$ distinct topological disks and $b{\geq}1$ points. Using the notion of symplectic chain complex, the present paper establishes a formula for computing Reidemeister torsion of the surface ${\Sigma}_{g,n,b}$ in terms of Reidemeister torsion of the closed surface ${\Sigma}_g$, Reidemeister torsion of disk, and Reidemeister torsion of punctured disk.

Isolated tubal torsion in the third trimester of pregnancy managed with simultaneous salpingectomy and cesarean section

  • Park, Seong Nam
    • Yeungnam University Journal of Medicine
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    • v.36 no.1
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    • pp.59-62
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    • 2019
  • Isolated tubal torsion is an uncommon cause of acute abdomen in pregnancy. Tubal torsion may occur in the absence of adnexal disease. Diagnosing tubal torsion is especially difficult in pregnancy because no precise preoperative radiological and biochemical investigations have been conducted. Most patients are diagnosed during surgery. Here, I present a case of isolated tubal torsion in a pregnant woman at 35 weeks and 6 days of gestation that was managed with salpingectomy and cesarean section simultaneously.

Measurement of blood base-excess concentration in cows with abomasal torsion and right-side displacement of the abomasum (제4위 우측전위증과 제4위 염전을 지닌 젖소에서 혈중 염기초과 농도의 측정)

  • Jeong, Soon-wuk
    • Korean Journal of Veterinary Research
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    • v.35 no.3
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    • pp.631-633
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    • 1995
  • 70 cows with abomasal torsion and 71 cows with right-side displacement of the abomasum were examined to determine whether the preoperative blood base-excess concentration could be used both as a prognostic indicator for postoperative recovery in cows with abomasal torsion and as an aid in differentiating between abomasal torsion and right-side displacement of the abomasum. The survival rate of cows with abomasal torsion decreased as the base-excess concentration decreased(P=0.08). There was a significant difference(P<0.025) among base-excess ranges between abomasal torsion and right-side displacement of the abomasum. Most cows with base-excess concentrations ${\geq}15.0mEq/L$ and ${\leq}-0.5mEq/L$ had abomasal torsion, rather than right-side displacement of the abomasum.

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Seismic behavior of reinforced concrete T-shaped columns under compression-bending-shear and torsion

  • Ping, Chen Zong;Weiwei, Su;Yang, Yang
    • Earthquakes and Structures
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    • v.20 no.4
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    • pp.431-444
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    • 2021
  • T-shaped column is usually used as side column in buildings, which is one of the weak members in structural system. This paper presented a quasi-static cyclic loading experiment of six specimens of reinforced concrete (RC) T-shaped columns under compression-flexure-shear-torsion combined loadings to investigate the effect in the ratio of torsion to moment (T/M) and axial compression ratio (n) and height-thickness ratio of flange plate (φ) on their seismic performance. Based on the test results, the failure characteristics, hysteretic curves, ductility, energy dissipation, stiffness degradation and strength degradation were analyzed. The results show that the failure characteristics of RC T-shaped columns mainly depend on the ratio of torsion to moment, which can be divided into bending failure, bending-torsion failure and shear-torsion failure. With the increase of T/M ratio, the torsion ductility coefficient increased, and in a suitable range, the torsion and horizontal displacement ductility coefficient of RC T-shaped columns could be effectively improved with the increase of axial compression ratio and the decrease of height-thickness ratio of flange plate. Besides, the energy dissipation capacity of the specimens mainly depended on the bending and shear energy dissipation capacity. On the other hand, the increase of axial compression ratio and the ratio of torsion to moment could accelerate the torsional and bending stiffness degradation of RC T-shaped columns. Moreover, the degradation coefficient of torsion strength was between 0.80 and 0.98, and that of bending strength was between 0.75 and 1.00.

Primary Omental Torsion (대망염전)

  • Kim, Seong-Chul;Kim, In-Koo
    • Advances in pediatric surgery
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    • v.3 no.1
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    • pp.68-70
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    • 1997
  • One case of primary omental torsion in a 10 year-old, 43 kg boy is presented. He presented with a history of acute, continuous pain in the upper abdomen, aggravated by changes of position. Physical examination of his abdomen showed board-like rigidity. tenderness and rebound tenderness over the entire abdomen. The preoperative diagnosis was perforated peptic ulcer. Exploratory laparatomy revealed torsion of the greater omentum. The torsed omentum was excised and the outcome was good. Omental torsion is a rare surgical condition and is difficult to diagnose prior to operation. Therefore, in case of negative exploration for acute abdomen, the omentum should be included among the organs examined. In addition, careful search for an inflammatory focus should be made, because secondary omental torsion with intraabdominal sepsis is much more common than primary torsion.

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The bending-shear-torsion performance of prestressed composite box beam

  • Wei, Hu S.;Yu, Zhao K.;Jie, Wei C.
    • Structural Engineering and Mechanics
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    • v.62 no.5
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    • pp.577-585
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    • 2017
  • To study the mechanical performances of prestressed steel-concrete composite box beam under combination of bending-shear-torsion, nine composite beams with different ratio of torsion to bending were designed. Torsion was applied to the free end of the beam with jacks controlled accurately with peripherals, as well as concentrated force on the mid-span with jacks. Based on experimental data and relative theories, mechanical properties of composite beams were analyzed, including torsional angle, deformation and failure patterns. The results showed that under certain ratio of torsion to bending, cracking and ultimate torsion increased and reached to its maximum at the ratio of 2. Three phases of process is also discussed, as well as the conditions of each failure mode.