FORMATION OF SURFACES CAD-MODELS USING SPECIALIZED SOFTWARE
DOI:
https://doi.org/10.32782/KNTU2618-0340/2020.3.2-2.6Keywords:
CAD model, frame of surface, plane contour, oscillation, monotonic change of differential geometric characteristicsAbstract
The modeling technology in the CAD system involves the formation of surfaces based on linear frames. The geometric characteristics of the frame elements (curved lines) determine the functional properties of the simulated surfaces. The modeling technique in the CAD system of surfaces of complex shape, based on the formation of contours that represent lines from the surface determinant with a given accuracy is proposed in this article.
The developed algorithms make it possible to determine the initial point series that belongs to any curve of the line and provide the specified interpolation accuracy when forming the contour. The software created on the basis of the developed technique was tested in modeling the functional surfaces of a planetary rotary compressor.
Models of the surfaces of the housing and rotor are formed based on the gear ratio of the gearing of the planetary-rotor mechanism and the dimensions of the rotor. In order to increase the compressor performance, optimization of the rotor working surfaces has been performed. The maximum volume of the working chamber is increased by increasing the radius of the movable gear of the planetary-rotor mechanism. In order to prevent jamming of the rotor during compressor operation, the rotor contour was changed. The initial contour of the formed circle was replaced by a contour interpolating a point row whose nodes were determined by a specially developed algorithm. The algorithm is based on determining the relative position of the body and rotor circuits at various times of the compressor. Modeling the compressor working surfaces required the formation of linear frame elements based on a point series obtained from the analytical representation of the curve and a point series obtained constructively.
The disadvantage of the proposed method is that it is based on the formation of only flat contours. The task of further research is the interpolation with a given accuracy of the point series that belong to spatial curved lines.
References
Light, R. & Gossard, D. (1982). Modification of Geometric Models through Variational Geometry. Computer Aided Design. 14, 4, 209–214.
Czerech, L., Kaczynski, R. & Werner, A. (2012). Machining Error Compensation for Objects Bounded by Curvilinear Surfaces. Acta Mechanica et Automatica. 6, 26–30.
Korotkiy, V. A., Usmanova, E. A. & Hmarova, L. I. (2016). Kompyuternoe modelirovanie kinematicheskih poverhnostey. Geometriya i grafika. 3, 4, 19-26.
Chekalin A. A., Reshetnikov M. K., Shpilev V. V, Borodulina S. V. (2017). Design of Engineering Surfaces Using Quartic Parabolas. Proceedings of the Innovative Technologies in Engineering: VIII International Scientific Practical Conference. (Russian Federation, Yurga, May 18-20, 2017 ), Bristol: Institute of Physics Publishing. Vol. 221. IOP Conference Series: Materials Science and Engineering. DOI:10.1088/1757-899X/221/1/012015.
Pérez-Arribas, F. & Pérez-Fernández, R. (2018). A B-Spline Design Model for Propeller Blades. Advances in Engineering Software. 118, 35–44.
Lai, T.-S. (2006). Design and Machining of the Epicycloid Planet Gear of Cycloid Drives. The International Journal of Advanced Manufacturing Technology. 28, 665–670.
Saini, D., Kumar, S. & Gulati, T.R. (2017). NURBS-Based Geometric Inverse Reconstruction of Free-Form Shapes. Journal of King Saud University Computer and Information Sciences. 29, 1, 116–133.
Zhang, Y., Ye, P., Wu, J. & Zhang, H. (2018) An Optimal Curvature-Smooth Transition Algorithm with Axis Jerk Limitations along Linear Segments. The International Journal of Advanced Manufacturing Technology. 95, 875–888.
Pessoles, X., Landon, Y. & Rubio, W. (2010). Kinematic Modelling of a 3-Axis NC Machine Tool in Linear and Circular Interpolation. The International Journal of Advanced Manufacturing Technology. 47, 639–655.
Holodnyak Yu.V. & Dmitriev Yu.A. (2016). Formirovanie odnomernyih obvodov s zakonomernyim izmeneniem kriviznyi. Dinamika sistem, mehanizmov i mashin. 3, 241–243.
Havrylenko, Y., Kholodniak, Y., Vershkov, O. & Naidysh, A. (2018). Development of the method for the formation of one-dimensional contours by the assigned interpolation accuracy. Eastern-European Journal of Enterpise Technology. 1, 4(91), 76–82.
