Analiza ruchu pewnego układu wibro-uderzeniowego o dwóch stopniach swobody

The paper deals with a vibratory-impact system with pneumatic suspension element and a movable stop. The experimental investigation of the model of a similar system (with a rigid stop) which had been carried out formerly by the author, proved an important feature of the system, namely the possibility of continuous control of impact frequency during the work of the system. The model considered in this paper consists of two masses, one of which represents the mass of a drived pile and the vibrating part of surrounding soil (the system investigated is to be applied to pile driving). Equations of motion are formulated and solved under the assumption of negligibility of energy dissipation in pneumatic suspension element. The main parameters of motion are calculated. The case of system with no energy dissipation received a special treatment. For that case the main parameters of motion were calculated. The structural stability conditions were formulated. The non-stationary motion caused by suddenly applied external force was considered as an analogy of the behaviour of a real system, while the drived pile passes the contact surface of two layers of soil. Some results of the analysis is presented by graphs. The formulae derived in the paper might be applied in the vibratory-impact pile drivers design.