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Purpose — The purpose of this paper is to assess the accuracy of homogenization or the smeared stiffness approach in analyzing quadrigrid plates under transverse loads is assessed by comparing two distinct finite element solutions. The grid is assumed to be made of homogeneous isotropic material. However, the numerical solution procedure adopted here is applicable to grids made of unidirectional composite ribs. Design/methodology/approach — The finite element structural analysis is conducted by using plate elements based on the first‐order shear deformable theory (FSDT) and grillage analysis using first‐order shear deformable beam elements. The grillage analysis results, which are taken as the exact results, are compared with the approximate results obtained using FSDT plate elements, where the stiffness matrices obtained by the smeared stiffness approach are incorporated in the plate finite element formulation. Several sample problems are solved and the influences of rib spacing, rib thickness‐to‐width ratio, plate dimensions, and loading are examined. Findings — The results presented here show that homogenization yields reliable results when certain conditions are satisfied. Originality/value — The paper demonstrates that it is necessity to conduct thorough and systematic research studies revealing the accuracy of these models, as the applicability limits of homogenization are not clearly known.

The purpose of this paper is to propose physically based varying fidelity surrogates to be used in structural design optimization of space trusses. The main aim is to demonstrate its efficiency in reducing the number of high fidelity (HF) runs in the optimization process.

In this work, surrogate models are built for space truss structures. This study uses functional as well as physical surrogates. In the latter, a grid analogy of the space truss is used thereby reducing drastically the analysis cost. Global and local approaches are considered. The latter will require a globalization scheme (sequential approximate optimization (SAO)) to ensure convergence.

Physically based surrogates were proposed. Classical techniques, namely Taylor series and kriging, are also implemented for comparison purposes. A parameter study in kriging is necessary to select the best kriging model to be used as surrogate. A test case was considered for optimization and several surrogates were built. The CPU time is reduced when compared with the HF solution, for all surrogate‐based optimization performed. The best result was achieved combining the proposed physical model with additive corrections in a SAO strategy in which C1 continuity was imposed at each trust region center. Some guidance for other engineering applications was given.

This is the first time that physical‐based surrogates for optimum design of space truss systems are used in the SAO framework. Physical surrogates typically exhibit better generalization properties than other surrogates forms, produce faster solutions, and do not suffer from dimensionality curse when used in approximate optimization strategies.

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.

A PRECISION Scribing and Lofting Table, which provides an accurate mechanical means whereby layout and lofting processes can be performed to close tolerances in the minimum of time, has been developed by Short Bros. & Harland Ltd.

Electric trucks are well known, but the various types and some of the advantages they give are not so widely appreciated. Electric trucks can travel around an area at a greater speed than a hand truck, can carry a greater load, and can stack it at any reasonable height. They also exert a psychological effect upon the worker. For example, the driver of a power truck is generally found to keep to his job more consistently than a manual trucker.

One of the most outstanding features of the post‐war world is the overwhelming wish on the part of the under‐developed and emergent nations to develop their own industries and join the ranks of the industrial society. It is an essential pre‐requisite to any programme for raising living standards in those countries. For one thing it is the only way that reasonably‐paid jobs can be provided in sufficient numbers, and then again, a rising standard of living requires the production of the material goods on which it is based and which can also form the basis for trade with other nations. This drive to more industrial self‐sufficiency has created, throughout the world, an enormous demand for trained personnel, particularly personnel with technical training at the technician and technologist level, and at the craftsman level too. The demand for trained office workers grows at the same time and there has been created a vast demand for language training in these countries. Britain has made a distinguished contribution to the satisfying of this need and the meeting of this need has already enabled Britain to build up a successful export trade in training technology covering both the supply of training equipment and the provision of complete systems and services, including the staff to go with it. Britain is now the most advanced teaching equipment and materials supplier in the world. Today this world‐wide service covers all grades of employee from shop‐floor workers to management. A great deal of the initiative has come from the commercial companies specialising in training equipment and services; much of their success rests on the fact that they work together within a co‐ordinating organisation, which they created and maintain, called ICETT, The Industrial Council for Educational and Training Technology Ltd. So successful has this venture been that 90 per cent of the output of these companies is sold outside Britain. This is an active, vigorous selling exercise in which Britain leads the field. And yet little is heard about it. In the article that follows ICETT tells its own story.

This paper proposes a bar‐system graph representation for structural topology optimization using a genetic algorithm (GA).

Based on graph theory, a graph is first used to represent a skeletal structure consisting of joining paths in the design domain, each of which is represented by a chain subgraph with finite number of vertices. Based on the edges of this graph, a bar‐system representation is proposed to define all the bars and the resulting topology is obtained by mapping each bar with its corresponding thickness to the design domain which is discretized into a regular mesh. The design variables are thus reduced to the spatial distribution of the vertices and the thickness of each bar. This method combines the advantages of both continuum and ground structure optimization methods.

The overall procedure is applied to classical structural topology optimization problems and its good performance is illustrated in the numerical examples.

It is suggested that the present representation method is both physically meaningful and computationally effective in the framework of topological optimum design using GAs.

In the following the methods and materials of construction used in the manufacture of sulphuric acid are described, from the handling and storage of raw materials right through to the acid concentration stage. There is a wealth of information contained in the article, all based on the authors' own experience with the sulphuric acid manufacturing division of Fisons Ltd. at Immingham, near Grimsby.

In America, the National Bureau of Standards is investigating the primary processes of corrosion to solve some of the practical engineering problems encountered today. Large single metal crystals are employed in some of the research to correlate corrosion with the arrangement of atoms in the crystal lattice. Other studies include the electrical phenomena, the mechanism of the formation of oxide films and the effect of illumination on the corrosion reaction.

To the Editor. DEAR SIR, In the June issue of AIRCRAFT ENGINEERING, Mr V. D. Naylor rightly asserts that, according to one‐dimensional theory, the velocity at the throat of a Laval nozzle is the local sonic velocity, whether friction is present or not. However his proof rests on an expansion law pvn=constant, when n≠y, and the throat velocity which he obtains differs according to the value of n. Both the assumption and the conclusion are false. The confusion which has existed on this point is, therefore, deepened.