Barbara Blazejczyk-Okolewska

Dynamics of impact oscillator with dry friction

Abstract Our investigations of the dynamics of a simple mechanical system show that (i) the structure of the bifurcation diagram seems to be independent of the friction models, and (ii) small changes of experimentally estimated parameters like friction and restitution coefficients (within the error of estimation) can lead to significant qualitative changes in the systems dynamics. The last observation shows that for such systems it is very difficult (if not impossible) to build mathematical models which can qualitatively describe experimental results for all possible values of system parameters.

Dynamics of the impact force generator

During the last years the interest of scientists in multibody mechanical systems in which the phenomenon of impact occurs has been still growing. Numerous investigations are carried out on the possibility of employing this phenomenon to increase the efficiency of operation of industrial machines or to eliminate those phenomena which are undesirable during machine operation. In the present paper a principle of operation of the impact force generator being an element of the rotor of the heat exchanger has been presented. Step disturbances of the rotational velocity of the rotor caused by the generator are aimed at intensification of the heat exchange process.

On Structural Patterns of Mechanical Systems with Impacts with One and Two Degrees-of-Freedom

Structural patterns of mechanical systems with impacts with one degree-of-freedom and two degrees-of-freedom, with elastic connections, have been identified and described. For their identification, a general method proposed by the author has been applied. This method uses (i) a matrix representation of the system with impacts, (ii) procedures that enable generations of all combinations of such systems as well as their identification and elimination of redundant equivalent combinations, and (iii) a procedure for elimination of disconnected systems.

A Method to Determine Structural Patterns of Mechanical Systems with Impacts

A structural classification of vibroimpact systems based on the principles given by Blazejczyk-Okolewska et al. (2004) has been proposed for an arbitrary finite number of degrees-of-freedom. A new matrix representation to formulate the notation of the relations occurring in the system has been introduced. The developed identification and elimination procedures of equivalent systems and identification procedures of connected systems enable the determination of a set of structural patterns of systems with impacts.