scholarly journals Cylindrical Shells Made of Stainless Steel – Investigation of Postbuckling

2017 ◽  
Vol 25 (2) ◽  
pp. 185-197
Author(s):  
Sebastian Stehr ◽  
Natalie Stranghöner

Abstract The relevant load case of open thin-walled shells is often wind loading during construction. Because of the missing stabilization effect of the roof they show a very high sensitivity to buckling which results into higher wall thicknesses. As part of the European RFCS research project BiogaSS the Institute for Metal and Lightweight Structures of the University of Duisburg-Essen carried out investigations on open thin-walled tanks made of austenitic and duplex stainless steels under wind load to study a possible economic advantage which might be gained from the consideration of the elastic postbuckling behaviour. This contribution presents not only experimental and numerical results but also first recommendations regarding the range of possible buckling reduction factors which might be incorporated in future revisions of EN 1993-1-6 and EN 1993-4-2.

Author(s):  
Gerald B. Feldewerth

In recent years an increasing emphasis has been placed on the study of high temperature intermetallic compounds for possible aerospace applications. One group of interest is the B2 aiuminides. This group of intermetaliics has a very high melting temperature, good high temperature, and excellent specific strength. These qualities make it a candidate for applications such as turbine engines. The B2 aiuminides exist over a wide range of compositions and also have a large solubility for third element substitutional additions, which may allow alloying additions to overcome their major drawback, their brittle nature.One B2 aluminide currently being studied is cobalt aluminide. Optical microscopy of CoAl alloys produced at the University of Missouri-Rolla showed a dramatic decrease in the grain size which affects the yield strength and flow stress of long range ordered alloys, and a change in the grain shape with the addition of 0.5 % boron.


Alloy Digest ◽  
1996 ◽  
Vol 45 (9) ◽  

Abstract Avesta Sheffield SAF 2507 is an austenitic/ferritic duplex stainless steel with very high strength. The alloy has a lower coefficient of thermal expansion and a higher thermal conductivity than austenitic stainless steels. The alloy has a high resistance to pitting, crevice, and general corrosion; it has a very high resistance to chloride stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-652. Producer or source: Avesta Sheffield Inc.


Author(s):  
T.Y. Chang ◽  
J.E. Zucker ◽  
K.L. Jones ◽  
N.J. Sauer ◽  
B. Tell ◽  
...  

1998 ◽  
Vol 25 ◽  
pp. 219-262 ◽  
Author(s):  
Bruce L. Mouser

Palavers, great meetings, grand conferences, “tribal” meetings— these are terms used to describe meetings among peoples in and near Sierra Leone, meetings in which political, diplomatic, and economic questions are discussed and sometimes resolved at the village, intervillage, and occasionally, national levels. These conferences vary in size and importance, depending on dimensions of conflicts or questions to be resolved. This paper focuses on one such conference that convened at Forékariah, the capital of Moria, in 1805 and on circumstances leading to it. It is based largely upon a lengthy first-hand report deposited at the University Library, University of Illinois at Chicago. This paper is presented in two parts: a description of the conference and its placement in Sierra Leone and Morian histories, and the text of the report produced by Sierra Leone observers.From the earliest records of British officials at Sierra Leone, there are citations to specific “indigenous” meetings and allusions to others that supposedly occurred (indeed they would have had to occur for certain events to follow). One of the earliest large conferences described in detail in these records is one that convened at Forékariah from 24 March to 6 April 1805. The extant contemporary written record of this conference was produced by Alexander Smith, the Sierra Leone Company's and Governor William Day's principal representative at the conference. Other observers from Freetown included William Francis, Andrew Moore, Captain Smith, and Charles Shaw. Alexander Smith did not identify a specific interpreter nor describe what method he used to record the detailed arguments presented by participants. Certainly the filter of language and inter pretation must have influenced the record's content. If one places the conference within the framework of Company and Sierra Leone history, however, and accepts the premise that the Freetown observers were relatively unbiased since they were not principal parties to the palavers resolved, the report can be seen as one of a very few in which Sierra Leone's officials presented themselves in such uninvolved fashion.


Author(s):  
D G Thomson ◽  
F Coton ◽  
R Galbraith

The aim of this article is to investigate the use of inverse simulation to help identify those regions of a ship's flight deck which provide the safest locations for landing a rotorcraft in various atmospheric conditions. This requires appropriate information on the wind loading conditions around a ship deck and superstructure, and for the current work, these data were obtained from wind tunnel tests of a ship model representative of a typical helicopter carrier/assault ship. A series of wind tunnel tests were carried out on the model in the University of Glasgow's 2.65 × 2.04 m wind tunnel and three-axis measurements of wind speed were made at various locations on the ship deck. Measurements were made at four locations on the flight deck at three different heights. The choice of these locations was made on the basis of preliminary flow visualization tests which highlighted the areas where the most severe wind effects were most likely to occur. In addition, for the case where the wind was from 30° to starboard, measurements were made at three further locations to assess the extent of the wake of the superstructure. The generated wind profiles can then be imposed on the inverse simulation, allowing study of the vehicle and pilot response during a typical landing manoeuvre in these conditions. The power of the inverse simulation for this application is demonstrated by a series of simulations performed using configurational data representing two aircraft types, a Westland Lynx and a transport helicopter flying an approach and landing manoeuvre with the worst atmospheric conditions applied. It is shown from the results that attempting to land in the area aft of the superstructure in a 30° crosswind might lead to problems for the transport configuration due to upgusts in this area. Attempting to perform the landing manoeuvre in an aggressive manner is also shown to lead to diminished control margin in higher winds.


2009 ◽  
Vol 62 (9) ◽  
pp. 1859-1872 ◽  
Author(s):  
Patrick Rabbitt ◽  
Mary Lunn ◽  
Said Ibrahim ◽  
Lynn McInnes

A sample of 4,314 volunteers who, when first recruited, were aged from 41 to 93 years were quadrennially tested from 2 to 4 occasions during the next 4 to 20 years on the Cattell Culture Fair intelligence test, 2 tests of information-processing speed, the Wechsler Adult Intelligence Scale (WAIS) vocabulary test, and 3 memory tests. After significant effects of practice, sex, demographics, socio-economic advantage, and recruitment cohort had been identified and considered, performance on all tests declined with age. These age-related declines accelerated for the Cattell and WAIS, 2 tests of information speed, and 2 of the memory tests. For all tests individuals’ trajectories of age-related change diverged with increasing age but, unexpectedly, were not affected by demographic factors. Practice gains from an initial experience of the cognitive tests remained undiminished as the interval before the second experience increased from 4 to 8 + years.


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