Archive of Mechanical Engineering

The aim of this research was to develop a composite material to be used as an elastomeric core of the artificial intervertebral disc. Two types of polyurethane composites with non-modified SiO2 and SiO2 modified NH2 group were obtained. The composites made of these materials have different filler content. The effect of modifying fillers for the structure and properties of these materials were investigated.

Efficiency, functionality and performance of the grain grinding process are significantly influenced by phenomena that are difficult to describe and occur in the working area of the grinder. In a machine-based, multi-disc grinding of grain biomaterials, the design of the quasi-cutting unit, volumes, sections of transport/grinding holes, their motion and the design features of the discs (the grinding unit) must facilitate the functions of grinding in the inter-hole space (with minimum energy-consumption of the process and maximum efficiency) and minimising undesirable phenomena related to mixing and transport. The pre-requisite for optimisation of the quasi-cutting unit design is a mathematical model. Among many aspects of the problem, this study describes a sample procedure resulting in a filling model for a biomass grain quasi-cutting unit including an initial verification of the same under conditions of the evaluation of maize and triticale grain grinding efficiency, using an innovative multi-hole 5-disc and 7-disc grinder.

The authors describe the program undertaken at the Warsaw University of Technology (WUT), aimed at developing mobile aerodynamic laboratories to be used for investigation into aerodynamic properties of airfoils or lightweight propulsion systems - in natural scale and in natural atmosphere. The enterprise was named the EB-program, and has both: research and educational aspects; in all phases of the program (i.e. design, manufacturing and testing) the WUT students are involved. As the result of work, three mobile aerodynamic laboratories were build: EB-1 - which was tested on the car roof, EB-2 - unique flying laboratory based on the PW-6 glider, and EB-3 - a new generation of flying wind tunnel to be used on the AOS-71 glider, which currently is under preparation to the flight tests. The authors present in detail the measurement systems and procedures supported by the Lab View software.

The following paper presents the solution to the problem of searching the best shape - structural form of the bottoms and optimal dimensions of the main cylinder of the carding machine with consideration to the criterion of minimal deflection amplitude. The ANSYS package of the Finite Element Method has been used for the analysis. Polak-Ribery conjugate gradient method has been applied for searching the optimal solution, basing on the parametric model of the cylinder written with the use of Ansys Parametric Design Language. As a result of the performed analyses, reduction of maximum deflection value at approximately 80 percent has been obtained. Optimal cylinder dimensions enable application of a new textile technology - microfibre carding and improvement in the quality of traditional carding technology of woollen and wool-like fibres.

The aim of this article is to present the design procedure for determining modification coefficients of toothed wheels of involutes planetary gear train with internal conjunction of teeth. It is possible to obtain a higher load-carrying capacity which depends also on correction coefficients. For example, we take into consideration a concept of planetary gears in which the teeth can be corrected, which allows better fatigue and contact surface strength. Two cases are considered when the namely zero center distance (without corrections) of the central and satellite wheels is the same or not, in relation to the zero center distance between the satellite and the sun wheel. Geometrical dimensions are described with regard to the technological teeth correction scope, and inequality restriction conditions are determined with respect to the ISO standards recommendations and the literature. The procedure can be applied to any other planetary gears with another kinematic connection of wheels.

Assessing the modern constructions of barrel weapon systems, one can rightly claim that they have achieved a high level of development both in terms of construction and technology. This is confirmed by the fact that it is quite rare for new solutions to appear in this area, with regard to their operational concept. It is also confirmed by many existing classifications of barrel weapons, taking into account the present constructional solutions used. In the present paper, the author described a new type of mechanism, which as for its operational concept, consists in separating the breech parts, being used in the weapons class of a short recoil barrel. The principle of its operation and constructional solution have also been presented, along with the mechanism that has been used so far, which enables us to show the basic operational difference between the two. In order to assess the value of the proposed mechanism, an analysis has also been made of parameters characterizing its operation, contrasted with the parameters of the mechanism used so far. This comparison has been drawn, taking into account the same object of reference, i.e. the NS-23 gun. In the summary, conclusions have been presented assessing the merits of the new solution.