11. Winding the tubes of rectangular section using dowels

Annotation: The tubes of rectangular section made of composite material find ever- growing use. Winding of tubes without using dowels for small winding angles has a number of disadvantages. The technology of winding through dowels does not have these disadvantages. The paper presents the authors-developed calculation technique for programs of winding the tubes of rectangular section made of composite materials using dowels. To ensure winding continuity, the dowels at base must have equal distances between them. The external diameter of comb is selected with margin taking into account band stranding on the dowels. The scheme of winding on entire layer is determined that represents a table which indicates band position between the dowels of front and rear comb during winding a layer for each coil. Then the coordinates of machine tool are determined. For this purpose, we determine the angles of coil winding, corresponding angles of mandrel turn in determined coordinates X, the coordinates of band escape point, angle of inclination of free section of band, then from geometrical considerations we obtain the components of unit vector of tangent to reinforcing trajectory and directly the coordinated of machine tool actuators. As a result, we obtain the table of coordinates of machine toll actuators during winding of the first coil (at forward and back travel). Using the presented logics, similarly it is easy to obtain for all coils the coordinates of machine tool actuators. According to this technique, the Vitok auto-programming system was developed in MathCad environment. The Vitok system was used during development of winding program for tube 28x28x2 mm under Sich-2M program. The programs operated successfully. The test samples of tubes were wound. The authors performed winding of the tubes of rectangular section made of composite material to obtain a structure with zero linear thermal expansion coefficient.