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Article

H.D. Conway

THIS paper is intended as a sequel to a paper by Dr. J. F. C. Conn entitled “Vibration of a Truncated Wedge” (AIRCRAFT ENGINEERING, Vol. XVI, April 1944, pp. 103–105). The…

Abstract

THIS paper is intended as a sequel to a paper by Dr. J. F. C. Conn entitled “Vibration of a Truncated Wedge” (AIRCRAFT ENGINEERING, Vol. XVI, April 1944, pp. 103–105). The three modes of vibration—longitudinal, flexural and torsional—of a truncated cone encastré at one end and free at the other are considered separately. Special attention is given to the vibration frequencies of the cone and uniform cylinder.

Details

Aircraft Engineering and Aerospace Technology, vol. 18 no. 7
Type: Research Article
ISSN: 0002-2667

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Article

H.D. Conway

IN a previous paper by the author (‘The Calculation of Frequencies of Vibration of a Truncated Cone’, AIRCRAFT ENGINEERING, Vol. XVIII, July 1946, pp. 235–236) expressions…

Abstract

IN a previous paper by the author (‘The Calculation of Frequencies of Vibration of a Truncated Cone’, AIRCRAFT ENGINEERING, Vol. XVIII, July 1946, pp. 235–236) expressions for the fundamental frequencies of longitudinal, flexual and torsional vibrations were obtained. The methods used have now been extended to include the vibrations of truncated pyramids encastré at one end and free at the other, and the results obtained are given in this paper. Special attention is given to the pyramids having equilateral triangle and square cross‐sections.

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Aircraft Engineering and Aerospace Technology, vol. 20 no. 5
Type: Research Article
ISSN: 0002-2667

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Article

H.D. Conway

IN a previous paper (AIRCRAFT ENGINEERING, Vol. XIX, February 1947, pp. 52–4) expressions were derived for the maximum bending moment and shearing force in vessels closed…

Abstract

IN a previous paper (AIRCRAFT ENGINEERING, Vol. XIX, February 1947, pp. 52–4) expressions were derived for the maximum bending moment and shearing force in vessels closed at one end and subjected internally to (a) gas pressure, (b) hydrostatic pressure. The method of solution has been extended in this paper to include the cases of cylindrical vessels, closed at both ends by flat plates or hemispherical shells and subjected to gas pressure.

Details

Aircraft Engineering and Aerospace Technology, vol. 20 no. 10
Type: Research Article
ISSN: 0002-2667

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Article

H.D. Conway

USING the general theory of cylindrical shells, expressions have been derived for the maximum bending moment and shearing force in vessels closed at one end and subjected…

Abstract

USING the general theory of cylindrical shells, expressions have been derived for the maximum bending moment and shearing force in vessels closed at one end and subjected internally to (a) gas pressure, (b) hydrostatic pressure. The method has been used by S. Timoshenko (Theory of Plates and Shells, McGraw‐Hill, pp. 412–3) for the special case where one end of the vessels is built into a rigid foundation.

Details

Aircraft Engineering and Aerospace Technology, vol. 19 no. 2
Type: Research Article
ISSN: 0002-2667

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Article

Berna Ulutas and Tugba Saraç

The facility layout problem aims to assign machines/departments to locations and modeled as a quadratic assignment problem (QAP). Multi period facility layout is a special…

Abstract

Purpose

The facility layout problem aims to assign machines/departments to locations and modeled as a quadratic assignment problem (QAP). Multi period facility layout is a special case of this problem where the sum of material handling and re‐layout costs are minimized. Since the problem is proved to be NP‐hard, several exact and heuristic methods are proposed in the literature. The purpose of this paper is to solve the multi period layout problem by using the modified sub‐gradient (MSG) algorithm for the first time and to determine its parameters.

Design/methodology/approach

The MSG algorithm can solve a large‐scale of optimization problems that also includes multi period facility layout. Since the performance of the algorithm depends on parameters, a design of experiment is made to determine the appropriate parameter values.

Findings

The proposed method evaluates the parameters of the MSG algorithm and most suitable general algebraic modeling solvers. It is observed that the parameter α value and solver type have main effects for small and large size test problems. Further, the results stated that solver type has more influence on large size test problem.

Research limitations/implications

This study is limited with the determination of the MSG algorithm parameters and solver types on the well known small and large size test problems. Further studies may include other test problem results obtained from the presented MSG algorithm parameters and compare them with best known results in the literature.

Originality/value

The paper determines the parameters of the MSG algorithm that is used to solve the multi period layout problem, for the first time in the literature.

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Article

This American textbook, originally reviewed in AIRCRAFT ENGINEERING, Vol. xvi, June, 1944, p. 170, has now been made available in Great. Britain, so attention may again be…

Abstract

This American textbook, originally reviewed in AIRCRAFT ENGINEERING, Vol. xvi, June, 1944, p. 170, has now been made available in Great. Britain, so attention may again be called to it as it provides a practical means of applying analytical geometry to aircraft lofting. The author is head of Engineering Loft' Mathematics at North American Aviation, Inc. He thus occupies a position which has no counterpart in the average British firm, and the book is interesting as an insight into modern American methods.

Details

Aircraft Engineering and Aerospace Technology, vol. 19 no. 6
Type: Research Article
ISSN: 0002-2667

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Article

The new Fair Trading measure aims at the establishment of a strong, bioadly‐based central direction of consumer protection; a new Director‐General of Fair Trading with…

Abstract

The new Fair Trading measure aims at the establishment of a strong, bioadly‐based central direction of consumer protection; a new Director‐General of Fair Trading with wide responsibilities “for protecting consumers” with authority to “make proposals for the exercise of order‐making powers in relation to trading practices which adversely affect consumer interests”, and “to act against those who persistently follow a course of conduct unfair to consumers”. This supremo is to work closely with the Monopolies and Mergers Commission and the Restrictive Practices Board, and no less than five junior Ministers are to be given special responsibilities for protecting consumer interests, handling these aspects of the new system in their own departments.

Details

British Food Journal, vol. 75 no. 2
Type: Research Article
ISSN: 0007-070X

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Article

Roy A. Liming

THE problem involved in obtaining satisfactory surface contours for assemblies such as are required in modern aircraft development demands for its successful solution the…

Abstract

THE problem involved in obtaining satisfactory surface contours for assemblies such as are required in modern aircraft development demands for its successful solution the co‐ordinated, concentrated efforts of all those concerned with both the design and manufacturing processes. Even the casual observer can see that, if optimum performance is to be realized, the external skin or covering, whether made of thin sheet stock or precision machined from heavier plate stock, must be continuously smooth.

Details

Aircraft Engineering and Aerospace Technology, vol. 19 no. 7
Type: Research Article
ISSN: 0002-2667

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Article

Under this heading arc published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United…

Abstract

Under this heading arc published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued

Details

Aircraft Engineering and Aerospace Technology, vol. 23 no. 10
Type: Research Article
ISSN: 0002-2667

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Article

Shun Wang, Qingchang Tan and Zunquan Kou

The purpose of this paper was to construct lubrication model closer to the fact of thrust bearings and to calculate the bearings characteristics of lubrication for…

Abstract

Purpose

The purpose of this paper was to construct lubrication model closer to the fact of thrust bearings and to calculate the bearings characteristics of lubrication for understanding how structures influence bearings performances and, importantly, what can be the most beneficial. Large-scale composite thrust bearings with Polytetrafluoroethylene (PTFE)-faced sector pad backed by steel base are used increasingly in equipment. But there are plenty of puzzled problems in design and application.

Design/methodology/approach

The authors established a 3D thermal elastohydrodynamic lubrication (TEHL) model. Oil film was formulated by Reynolds equation for pressure, and by energy equation for temperature varying through oil film thickness. Meanwhile, pad temperature was formulated by solid heat transfer equation. Elastic and thermal deformations of pad surface were calculated. Viscosity and density of oil were valued separately under different pressure and temperature. Load balance was considered as well as overturning moment balance. Finite difference method was applied to discrete these equations.

Findings

PTFE layer and steel base have either helpful or detrimental impact on contact strength and full film lubrication of thrust bearing depending on their relationship in thickness. Temperature lag between middle layer of steel base and pad surface depends on PTFE layer, but not on the steel base. PTFE layer thickness should be considered when alarming threshold value of the bearings temperature is chosen.

Originality/value

Three-dimensional TEHL model of large-scale composite thrust bearings was established, which included more factors close to the actual. Conclusions were drawn. These proposals are helpful to design the bearings.

Details

Industrial Lubrication and Tribology, vol. 68 no. 1
Type: Research Article
ISSN: 0036-8792

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