scholarly journals Axial-torsion behavior of superelastic tubes: Part I, proportional isothermal experiments

2020 ◽  
Vol 199 ◽  
pp. 1-35 ◽  
Author(s):  
Benjamin Reedlunn ◽  
William S. LePage ◽  
Samantha H. Daly ◽  
John A. Shaw
Keyword(s):  
2014 ◽  
Vol 2014 (sep05 1) ◽  
pp. bcr2014205558-bcr2014205558 ◽  
Author(s):  
R. Sachan ◽  
M. L. Patel ◽  
P. Sachan ◽  
A. Arora

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Zengliang Gao ◽  
Tianwen Zhao ◽  
Xiaogui Wang ◽  
Yanyao Jiang

Uniaxial, torsion, and axial-torsion fatigue experiments were conducted on a pressure vessel steel, 16MnR, in ambient air. The uniaxial experiments were conducted using solid cylindrical specimens. Axial-torsion experiments employed thin-walled tubular specimens subjected to proportional and nonproportional loading. The true fracture stress and strain were obtained by testing solid shafts under monotonic torsion. Experimental results reveal that the material under investigation does not display significant nonproportional hardening. The material was found to display shear cracking under pure shear loading but tensile cracking under tension-compression loading. Two critical plane multiaxial fatigue criteria, namely, the Fatemi–Socie criterion and the Jiang criterion, were evaluated based on the experimental results. The Fatemi–Socie criterion combines the maximum shear strain amplitude with a consideration of the normal stress on the critical plane. The Jiang criterion makes use of the plastic strain energy on a material plane as the major contributor to the fatigue damage. Both criteria were found to correlate well with the experiments in terms of fatigue life. The predicted cracking directions by the criteria were less satisfactory when comparing with the experimentally observed cracking behavior under different loading conditions.


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Hiromitsu Nagata ◽  
Hiroyasu Nishizawa ◽  
Susumu Mashima ◽  
Yasuyuki Shimahara

Abstract Background Meckel’s diverticulum is considered the most prevalent congenital anomaly of the gastrointestinal tract. Approximately 4% of patients are symptomatic with complications such as bleeding, intestinal obstruction, and inflammation, while axial torsion of Meckel’s diverticulum is rare, particularly in pregnancy. Case presentation A 31-year-old woman in week 15 of pregnancy complained of epigastric pain, nausea and vomiting. Clinical diagnosis was severe hyperemesis gravidarum. Because the symptoms persisted during hospitalization, CT was performed and revealed dilated small bowel loops with multiple air-fluid levels. In the right mid-abdomen, there was a large part of air containing a cavity connected to the small intestine, which was considered a dilated bowel loop. Emergency laparotomy was performed and axial torsion of a large Meckel’s diverticulum measuring 11 cm was found at a few centimeters proximal to the ileocecal valve. Ileocecal resection including Meckel’s diverticulum was performed. The postoperative course was uneventful. At 40 weeks gestation, she had vaginal delivery of normal baby. Conclusion The physiological and anatomical changes in pregnancy can make a straightforward clinical diagnosis difficult. Prompt diagnosis and management were needed in order to avoid significant maternal and fetal risks. The use of imaging examinations, especially CT examination, with proper timing may be helpful to prevent delay in diagnosis and surgical intervention. Here, we report the case of a patient with axial torsion of Meckel’s diverticulum in pregnancy. To our knowledge, axial torsion of Meckel’s diverticulum in the first trimester of pregnancy has not been reported in the English medical literature.


2014 ◽  
Vol 8 (2) ◽  
pp. 63-64
Author(s):  
R Varadarajan ◽  
N Shivalingaiah

Torsion of the uterus is rare and mainly involves pregnant uterus. A combination of ovarian torsion with an axial torsion of uterus in a non-gravid woman is extremely rare. The exact incidence of uterine torsion is not clearly established, as only few case reports are available in the literature. Usually this kind of torsion are per operative diagnosis and very difficult to diagnose pre operatively. Here we present one such case with a combined ovarian and axial torsion of uterus.Nepal Journal of Obstetrics and Gynaecology / Vol 8 / No. 2 / Issue 16 / July-Dec, 2013 / 63-64 DOI: http://dx.doi.org/10.3126/njog.v8i2.9775


2015 ◽  
Vol 143 (1-2) ◽  
pp. 79-82
Author(s):  
Sasa Radovic ◽  
Drago Albijanic ◽  
Marko Albijanic ◽  
Zoran Krstic

Introduction. Meckel?s diverticulum (MD) is the most prevalent congenital anomaly of small intestine. It develops due to the incomplete obliteration of omphalomesenterict duct which normally undergoes obliteration during the seventh week of gestation. In the majority of cases MD is asymptomatic but it may cause various complications, such as bleeding, intestinal obstruction and inflammation. Cases of umbilical sinuses, fistulas and neoplasms related with MD have been reported, but extremely rare gangrene due to its axial torsion, especially in children, as is the case of our patients. Case Outline. An 11-year-old boy admitted to hospital due to 24 hours epigastric pain, vomiting and malaise. After a complete physical examination, and appropriate pre-surgical laboratory and radiographic tests, surgical exploration was performed with a midline abdominal incision. On 60th cm proximal to the ileocecal valve we found a long and in a narrow based ganrenous MD with axial torsion and fibrotic cord extending from the tip of MD to the ileal mesentery. Surrounding ileum had normal appearance. A demarcation and subsequent resection of MD and the surrounding ileum was performed with endto- end ileal anastomosis. Postoperative recovery was successful and the patient was discharged after six days. Conclusion. Axial torsion of MD is presented with non-specific abdominal symptoms and difficult preoperative diagnosis. The choice of diagnosis and therapy is surgical exploration and resection of MD.


2021 ◽  
Vol 12 ◽  
pp. 1
Author(s):  
Chibueze Onyemkpa ◽  
Benjamin Kuhns ◽  
Thomas Murickan ◽  
Crystal Drayer ◽  
Kosisochi Obinwanne

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