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The purpose of this paper is to develop the method for the calculation of residual stress and enduring deformation of helical springs.

For helical compression or tension springs, a spring wire is twisted. In the first case, the torsion of the straight bar with the circular cross-section is investigated, and, for derivations, the StVenant’s hypothesis is presumed. Analogously, for the torsion helical springs, the wire is in the state of flexure. In the second case, the bending of the straight bar with the rectangular cross-section is studied and the method is based on Bernoulli’s hypothesis.

For both cases (compression/tension of torsion helical spring), the closed-form solutions are based on the hyperbolic and on the Ramberg–Osgood material laws.

The method is based on the deformational formulation of plasticity theory and common kinematic hypotheses.

The advantage of the discovered closed-form solutions is their applicability for the calculation of spring length or spring twist angle loss and residual stresses on the wire after the pre-setting process without the necessity of complicated finite-element solutions.

The formulas are intended for practical evaluation of necessary parameters for optimal pre-setting processes of compression and torsion helical springs.

Because of the discovery of closed-form solutions and analytical formulas for the pre-setting process, the numerical analysis is not necessary. The analytical solution facilitates the proper evaluation of the plastic flow in torsion, compression and bending springs and improves the manufacturing of industrial components.

FOR some time industry has been preoccupied with the question of management. It is generally agreed that in the United States the services of management consultants are engaged by at least 75 % of the principal industrial enterprises, hospitals and chief educational establishments. In this country, too, there is growing reliance on the same kind of aid.

THE B.M.W.801 is an air‐cooled, 14‐cylinder, 4‐strokc, 2‐row radial, fuel‐injection engine with reduction gear and engine‐driven cooling‐fan. Supercharging is by a single‐stage centrifugal blower with two automatic speed changes (Figs. 1 and 2).

DRAUGHTSMEN can make a major contribution to productivity provided they are trained in work study. This fact emerged from a paper presented by Mr. B. A. Dyson, General Manager (Overseas Production) of Hoover Ltd., to a joint work study conference organised by the British Institute of Management.

This paper investigates the relationship between prior planning and the practical adaptation and improvisation conducted by organizations during the COVID-19 pandemic through a qualitative case study of Norwegian Public Health Institutions.

This paper draws on a unique set of qualitative data, interviews and field observations, gathered from organizations during an ongoing crisis. Through this access it becomes possible to examine how organizations practically navigated the complex relationship between structured plans and the situational, short term forms of crisis communication.

The paper finds that prior plans played a key role as points of reference, and as a prior set of principles that could be drawn on during a crisis. Organizations did however have to adapt and respond to the crisis in ways that could not have been designed in advance. In order to do so employees would deliberate and discuss in search of a fitting response that could help them in reaching their goals.

The paper builds on prior work that has discussed limitations and challenges to planning and linear approaches in crisis communication and strategic communication, but provides empirical insight into how members of organizations navigate this work in practice. By employing theories from rhetoric it provides a framework for the further study of crisis communication as a practical ongoing activity, and provides some suggested implications for how organizations can prepare increase crisis preparedness.

THE basic method of air navigation is deduced reckoning or simply dead reckoning. The method comprises the maintenance of an air pilot, which is made by calculating true airspeed and hence air distance run and then plotting this along the aircraft's heading from some initial ground fix. Subsequent ground positions may then be deduced by laying off the wind vector from the air position. As an example (Fig. 1) suppose an aircraft flics for one hour on a true heading of 060 deg. starting from an initial ground position A. If the true airspeed is 180 knots the air position will be at B, and if the mean wind over the flight is 45 knots from 340 deg. true then the ground position (by D.R.) corresponding to an air position at B would be at C. Now if the aircraft flics for the next hour on a true heading of 085 deg. and the mean wind over this hour is 30 knots from 310 deg. true, the air position with respect to A would be at D and the ground position at F. If a new air plot had been started at C then the air position, at the end of the second hour, would be at E and the ground position (by D.R.) again at F.

WINDING high tensile steel wire on cylinders, or pressure vessels to increase their strength and resistance to internal stresses, is not a new principle. The Royal Ordnance Factories strengthened gun barrels in this way during the 1914–18 war, and in the years since the Royal Aircraft Establishment, Farnborough, has experimented with pressure vessels (fig. 1). The application of two layers of wire is intended to give a ‘fail safe’ condition to damp down the effects of a burst cylinder.

The purpose of this study is to present a finite element (FE) implementation of phenomenological three-dimensional viscoelastic and viscoplastic constitutive models for long term behaviour prediction of polymers.

The method is based on the small strain assumption but is extended to large deformation for materials in which the stress-strain relation is nonlinear and the concept of incompressibility is governing. An empirical approach is used for determining material parameters in the constitutive equations, based on measured material properties. The modelling process uses a spring and dash-pot and a power-law approximation function method for viscoelastic and viscoplastic nonlinear behaviour, respectively. The model improvement for long term behaviour prediction is done by modifying the material parameters in such a way that they account for the current test time. The determination of material properties is based on the non-separable type of relations for nonlinear materials in which the material properties change with stress coupled with time.

The proposed viscoelastic and viscoplastic models are implemented in a user material algorithm of the FE general-purpose program ABAQUS and the validity of the models is assessed by comparisons with experimental observations from tests on high-density polyethylene samples in one-dimensional tensile loading. Comparisons show that the proposed constitutive model can satisfactorily represent the time-dependent mechanical behaviour of polymers even for long term predictions.

The study provides a new approach in long term investigation of material behaviour using FE analysis.

PARLIAMENT passed the Equal Pay Act in 1970 and it comes into full force at the end of 1975. In the meantime a Government order could increase the pay of women to at least 90 per cent of men's by December 31st next year. Like other legislative forays into the industrial world in recent years, this Act, despite its deceptively simple title, bristles with problems and will greatly change the country's economic life.

IT IS QUITE a few years ago that we reported cases of university graduates forced to take jobs as labourers or suchlike because no other work was available. Indeed, our editorial last month dealt with such a case although that one had a much happier outcome.