• MACHINES

    ANALYSIS OF KINEMATICS AND KINETOSTATICS OF FOUR-BAR LINKAGE MECHANISM BASED ON GIVEN PROGRAM

    Machines. Technologies. Materials., Vol. 11 (2017), Issue 9, pg(s) 429-434

    In this paper is presented Synthesis of a for-bar linkage mechanism of the lift car extrusion. In this mechanism are introduced even higher kinematic pairs. The movement of the mechanism is repeated periodically and it is sufficient to do its kinematic study for an angle 75 [deg]. The description of the mechanism movement can be performed in the grafoanalytical or analytical path by centers of speed moments, which belong to a narrow link and a loop of the center mechanism, and the instant centers belonging to the two related movements. In the kinematic analysis of the forward mechanisms are used graphical methods. These are simple and universal, making it possible to determine the positions, velocity and acceleration of the links of any structure. With the application of contemporary calculating technology, the graphical methods in the analysis of mechanisms take the right place. The velocity of each link of the mechanism linkage that performs the movement of the plane can be shown as very geometric of the instant center speed and the speed of rotation around the center of the instantaneous. The analysis will be performed by Math Cad software, while kinetostatic analysis will be carried out using Contour Method, comparing results of two different software‘s Math CAD and Working Model. The simulation parameters will be computed for all points of the contours of mechanism. For the simulations results we have use MathCad and Working Model software’s.

  • MECHANIZATION IN AGRICULTURE

    MATHEMATICAL MODEL OF COMPLEX MOVEMENT

    Mechanization in Agriculture, Vol. 63 (2017), Issue 1, pg(s) 3-10

    In theoretical study of most of agricultural machines working bodies there is a need of the modeling of material particles (material points) motion on their working surfaces. Questions of such modeling in cases when the specified surfaces are give to material points movement with difficult trajectories are especially difficult. Objective of this research is to develop the basic provisions of complex movement theory of material point. When carrying out research methods of modeling theory, theoretical mechanics, higher mathematics, in particular differential geometry, methods of drawing up programs and numerical calculations on the personal computer are used. As a result of the conducted theoretical research the complex movement of material point which relative movement happens in a moving trihedron of curve which is defined by the natural equations is considered. The figurative movement of a trihedron is defined by differential characteristics of curve. Competency of use of Frenet formulas for finding absolute speed and point acceleration in projections on unit vectors of the moving trihedron is proved. As a result of numerical calculations on the personal computer there were found absolute trajectories of material point movement and qualitative assessment of received results was carried out.