The properties of matrix operations and the properties of Hartenberg-Denavit's co-ordinate system's transformation matrices were used for deriving a dependence facilitating an easier determination of the links' angular velocity vectors in the link-related co-ordination systems. The use of derived dependence does not require determining products of transformation matrices nor inverse matrices. The numbers of necessary algebraic operations for previous and simplified dependences was set up. The use of a simplified dependence was illustrated by a numerical example.

A helicopter blade tip vortex generates impulsive noise of high intensity when it impinges upon the following blade. In the present work, the vortex is attenuated by coaxial swirling jet rotating in the opposite direction. The jet issues from a nozzle located at the blade tip. The nozzle was supplied with compressed air transported in the blade channel. The decrement of vortex strength is measured as a function of the compressed air pressure related to the dynamic pressure of the flow in the wind tunnel. It was found that the jet, even of relatively low intensity, considerably effects the blade tip vortex formation.

This work deals with the analysis of elasto-plastic post-buckling state of rectangular laminated plates subjected to combined loads, such as uniform compression and shear. The plates are built of specially orthotropic symmetrical layers. The analysis is carried out on the basis of nonlinear theory of orthotropic plates involving plasticity. The solution can be obtained in the analytical-numerical way using Prandtl-Reuss equations. The preliminary results of numerical calculations are also presented in figures.

The analysis of buckling, post-buckling behaviour and load carrying capacity of prismatic composite pole structures is conducted. The asymptotic expansion established by Byskov-Hutchinson is used in the second order approximation. The thin-walled tubular columns are simply supported at the ends and subject to the uniform compression. Several types of cross-sections with and without intermediate stiffeners are considered. The present paper is the continuation of a previous paper by the authors (1999) where the modal interaction of thin-walled composite beamcolumns was investigated.

The authors of this paper analysed Acoustic Emission (AE) signal generated in different stages of punch process, emitted from crank PMSC - 12 punch press. The details of the instrumentation used are described. The experimental part describes the influence of feedstock thickness and hardness to the intensity of the emitted signal. The final part of the investigation presents the changes of AE signal caused by simulated tool abrasive wear. The possibilities of AE monitoring of punching of thin plates are also discussed.

Theoretical analysis of the dewatering and consolidation process of the wet paper web with the air through- blowing technique is presented in this study. This kind of process takes place in a new (patented) device called the air press. The results of theoretical considerations are experimentally verified. The experimental research was conducted on a specially designed experimental stand with the use of three kinds of paper used for oil and air filtration. It was proven that the air through-blowing process of the fibrous web dewatering can be considered as unidirectional consolidation with the linear relationship of dehydration and deformation. A new system of devices was suggested for the continuous production of high quality filter papers, with the air press as its basic element.

Computer simulation of involute spur gears generation was used to determine tooth profiles mapped by tools during gear machining. These profiles were computed for different combinations of geometric parameters of machined gears and tools as well as for different combinations of pretreatment and finishing processes. Results of simulations were used for generation of very precise finite element models of representative gear segments. For these models, distributions of stresses were computed for assumed load in the ADINA finite element system. The results were compared with related results of computations made in accordance with the ISO/DIS and AGMA standards. Special attention was paid to gears, in which additional notch appears at tooth root after machining. This notch causes concentration of stresses. On the basis of the above named computations an analysis of influence of technological parameters and methods of machining gears on form and bending strength properties of spur gear tooth root was performed. General conclusions were formulated. They can be useful in both gear design and gear manufacturing for proper selection of structural parameters, association of pretreatment and finishing, selection of suitable method of gear generation and parameters of applied tool. Approach suggested in this paper: setting initial structural and technological parameters, computer simulation of gear generation, computer assisted strength analysis leading to suitable modification of the design and manufacturing presumptions - establishes proper basis for optimization of gears with consideration to the maximum possible bending strength properties of spur gear tooth root.

This paper presents requirements for meshing of simplified type of worm gears applied in fine mechanisms. There are given some geometrical dependencies referring to meshing of the worm with the thread made of wire (having circular section). The paper describes also a computer program aiding design of such kind of worm gears.

The helical jet is generated in a tangential pipe nozzle having the tangential and the axial inlets and the axial outlet. The flow directions in free jet spreading in the stationary air was measured by means of a flag type probe. The flow was visualized using the planar scattering technique. It was found that due to asymmetrical distribution of the tangential velocity in the jet leaving the nozzle, the air particles spread in the ambient with various intensity depending on the azimuthal angle. The result is that the jet has a spiral shape with bean-like cross-section.

The paper deals with the safety criteria of design for an infinite fatigue life of machinery parts. Uniaxial and multiaxial zero mean stress states are considered. In the latter case, constant-amplitude in-phase stress components, as well as random-amplitude synchronous stress components, are taken into account. Dimensionless and relative safety margins for these stress states are defined. The presented criteria refer to ductile materials showing true fatigue limits. Transformation rules in the plane are given for fatigue limits referenced to coordinate system different than the components of the plane stress.

In the paper, the Author presents the method of realisation of various scenarios of "test ride" on engine test bench. Research possibilities offered by semi-virtual system consisting of a real engine and a vehicle simulator are described. The previous article by the Author, "The Principles of Engine Operation Simulation in Test-bench Examination in the Conditions Equivalent to Traffic Exploitation of the Vehicle" [7] was devoted to the description of test requirements. Test accuracy, structure and equipment of the test stand were described there, as well as the characteristics of the software that controls the test and monitors its correctness.

In this paper, the Author presents a method of simulating various "test ride" scenarios for an automobile tested on engine test bench. The research possibilities offered by the semi-virtual system consisting of a real engine and vehicle motion simulator are underlined. The Author also describes the method of performing tasks in basic phases of vehicle testing. The following article by the Author, "The method of executing simulation procedures on engine test bench in traffic tests of combustion engines", will present requirements concerning test accuracy, structure and equipment of the test stand, and the characteristics of software that controls the tests and supervises its outcome.