Theoretical prediction of flange wrinkling in first-pass conventional spinning of hemispherical part

2017 ◽  
Vol 246 ◽  
pp. 56-68 ◽  
Author(s):  
Qingshuai Kong ◽  
Zhongqi Yu ◽  
Yixi Zhao ◽  
Hao Wang ◽  
Zhongqin Lin
2021 ◽  
Vol 62 ◽  
pp. 368-377
Author(s):  
Juan Huang ◽  
Junsong Jin ◽  
Lei Deng ◽  
Xinyun Wang ◽  
Pan Gong ◽  
...  

2017 ◽  
Vol 93 (9-12) ◽  
pp. 3583-3598 ◽  
Author(s):  
Qingshuai Kong ◽  
Zhongqi Yu ◽  
Yixi Zhao ◽  
Hao Wang ◽  
Zhongqin Lin

2019 ◽  
Vol 265 ◽  
pp. 44-55 ◽  
Author(s):  
S.W. Chen ◽  
P.F. Gao ◽  
M. Zhan ◽  
F. Ma ◽  
H.R. Zhang ◽  
...  

1963 ◽  
Vol 85 (1) ◽  
pp. 44-48 ◽  
Author(s):  
S. Kobayashi

The condition of flange wrinkling in conventional spinning of cones is established by modifying the theory of instability in deep-drawing of cups. Experiments conducted in order to test the theoretical results show that agreement exists between theory and experiments.


Author(s):  
Li Zixuan ◽  
Shu Xuedao ◽  
Ye Bohai ◽  
Wang Jitai

Abstract Conventional spinning is a kind of ancient revolving process which controls the product’s shape by roller trace design. It is also widely used in civil, military, automobile, aerospace and other fields. Unlike the power spinning process, the roller trace used in conventional spinning is complex. Both thickness uniformity and crack defects are affected by it. However, roller trace design is still based on experience without a solid theoretical basis. This paper simulated five different roller trace curves: involute curve, circular curve, Bezier curve, conchoids and line. Experiments using superalloy GH3030 were conducted in conjunction with a multi-pass conventional spinning simulation model. Blank thickness variations, mandrel and roller forces of different roller traces in the first pass are analyzed and assessed through the verification experiments. The results suggest that the curve trace parameters play a key role on the product thickness uniformity. And the distribution of Bezier and conchoid roller traces is more uniform than the other traces. The axial force of mandrel is a very important factor in the design of tool load capability. Larger roller feed ratio and proper roller traces can reduce the thinning which may avoid the cracks.


Author(s):  
Ann M. Thomas ◽  
Virginia Shemeley

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.


1997 ◽  
Vol 50 (2) ◽  
pp. 421-438 ◽  
Author(s):  
Daniel Zagar ◽  
Joel Pynte ◽  
Sylvie Rativeau
Keyword(s):  

2020 ◽  
Vol 77 (1) ◽  
pp. 14-19
Author(s):  
Stephan Krähenbühl
Keyword(s):  

Zusammenfassung. Für die Dosisangleichung bei Patienten mit Leberzirrhose gibt es keinen verlässlichen endogenen Parameter, der die metabolische Aktivität und das Ausmass der portacavalen Shunts repräsentiert. Die Angleichung muss deshalb unter Beachtung der pharmakokinetischen Eigenschaften der verabreichten Arzneistoffe erfolgen. Bei Arzneistoffen mit einem starken Abbau während der ersten Passage durch die Leber (first-pass Effekt) muss nach oraler Verabreichung mit einer Zunahme der Bioverfügbarkeit und verminderter Clearance gerechnet werden. Nach topischer, buccaler oder parenteraler Applikation spielt nur der Effekt auf die Clearance eine Rolle. Für Arzneistoffe mit einer hohen Bioverfügbarkeit (> 70 %) ist ebenfalls nur die hepatische Clearance entscheidend. In der Folge werden die in der Schweiz gebräuchlichen Opioide bezüglich pharmakokinetischer Eigenschaften und Konsequenzen bezüglich Dosisangleichung bei Patienten mit Leberzirrhose besprochen. Buprenorphin, Fentanyl, Hydromorphon, Morphin, Naloxon und Tapentadol sind Arzneistoffe mit einem hohen first-pass Effekt, währenddem Methadon, Oxycodon und Tramadol eine Bioverfügbarkeit von > 70 % aufweisen.


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