Minimax problem of determining the tape tension during winding on a compliant bobbin

The object of this report is to analyze the modes in which the tension on the inner turns drops when a tape or a thread are wound on a compliant bobbin as, for example, during processing of glass-plastic products. It is established here under what conditions one cannot possibly ensure a uniform residual tension in all turns upon completion of the winding; for this case, then, the optimum mode of tension change during winding is sought, so that the tension drop in the inner turns will be minimum.     

Calculation of the geodesic winding characteristics of glass-reinforced plastic shells of revolution

A method of determining the winding laws for filament-wound shells is considered. The method is based on a natural approach to the derivation of the equation of motion of the winder as a function of the rotation of the wound shell about its own axis.Moscow Bauman Higher Technical College. Translated from Mekhanika Polimerov, No. 6, pp. 1020–1025, November–December, 1970.     

Calculation of the deflection of a composite pipeline made by winding tubes

An estimate of the stress state of polymer cellular (hollow) pipe members is proposed, which is based on averaged components of the displacement vector. A calculation algorithm is presented that takes into account the effect of action of soil on the pipe surface where the normal displacements are positive.     

Zero-moment laminated cylindrical shells with variable elasticity parameters obtained by the continuous winding method

Conclusions The general solution in the displacements of the problem of thermal-force loading of a zero-moment laminated cylindrical shell with variable elasticity parameters has been obtained in analytic form. Boundary-value problems for the practically important and often realized boundary conditions which arise in tests of samples, models, and natural structures have been discussed.Presented at the Fifth All-Union Conference on the Mechanics of Polymer and Composite Materials (Riga, October, 1983).Translated from Mekhanika Kompozitnykh Materialov, No. 3, pp. 493–502, May–June, 1984.     

Cooperation between strands of practice: challenges and opportunities for the renewal of OR

Collaboration between OR groups following different ‘strands of practice’, namely adhering to different ways of conducting OR practice, is difficult. We demonstrate the existence of this problem in two contexts. Firstly, we found several different strands of practice within an independent, entrepreneurial OR firm. Though these strands had the potential to be highly complementary, their co-existence within one firm led to serious tensions and their potential synergy has not yet been realised. When the independent OR firm achieved successful renewal by transforming one of their strands of practice into a new approach to projects, this very success created a new set of competitive challenges. Secondly, an independent OR consulting firm working with a client's internal research group found that the latter's approach conflicted with its own, resulting in an unsuccessful project. We conclude that the ‘micro-level’ problems of collaboration between individual practitioners and between groups, though largely neglected in the OR literature, can be serious impediments to success and renewal of OR practice.     

Calculation of elasticity parameters of a material with defects

Conclusions 1. With the aid of averaging integrals, it is possible to arrive at various approximations for the elastic parameters of a material with microdefects in the form of plane cracks.2. These approximations differ appreciably in the case of high crack concentrations, with the use of a self-consistent field in both the Reiss model and the Voigt model yielding different results.3. In the absence of information about the microdefect structure in a material, the defectiveness parameters must be determined from a macrotest under conditions of a plane state of stress. The expressions derived on this basis will then yield predictions as to changes in the mechanical properties under other conditions of stress and loading.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 5, pp. 838–845, September–October, 1977.     

Gravity and the spiral model

The Spiral model, a generalization of Feynman's Chessboard model, is considered as a candidate for a realistic subquantum dynamical system. It can be shown that Dirac dynamics describe a subspace of the full dynamics of the model. Wave packet reduction and response to macroscopic measurement are both features which are being tested numerically. Assuming the model can mimic reduction, several new possibilities arise in the relation between quantum mechanics and gravity.     

A numerical method for the dynamics and stability of spiral waves

In this paper we propose a new method of investigating the change of dynamics in reaction-diffusion equations, which is based on approximating the Euclidian norm of state variables along with the introduction of phase space. Our method is simple in implementation and can be applied to study the dynamics of multiple spirals. The method is extended to study the stability of spiral waves by developing an algorithm which is applied to circular and meandering motions.     

Algorithmization of the control of the working mechanisms of machines for winding glass-reinforced plastic shells

Conclusions 1. A block diagram has been developed for solving the problem of the algorithmization and programming of the control of multicoordinate winding machines. This reduces the design process to four main steps.2. A general approach to the optimization of the tape-laying process with reference to a formulated quality criterion is presented.3. With this method, even in the design stage precise requirements can be formulated in respect of the working mechanisms and control systems with the object of either maximizing output or minimizing installed power.4. Relations between the TLP and TCP trajectories are obtained for motion of the working mechanisms along approximate trajectories. This problem is solved for the general case, irrespective of the form of the approximation and the type of wound surface.5. The optimum structure of the programmed control system is determined and the necessary coordination of the individual coordinate systems is found for large winding machines.For communication 1, see [1].V. I. Ul'yanov (Lenin) Leningrad Electrical-Engineering Institute. Translated from Mekhanika Polimerov, No. 3, pp. 435–442, May–June, 1978.