RESUMEN
Frames made of polymer composites are increasingly used in the aerospace, automotive, and agricultural industries. A frequently used technology in the production line of composite frames is winding rovings onto a non-load-bearing frame to form the structure using an industrial robot and a winding head, which is solidified through a subsequent heat-treatment pressure process. In this technology, the most difficult procedure is the winding of the curved parts of a composite frame. The primary concern is to ensure the proper winding angles, minimize the gaps and overlaps, and ensure the homogeneity of the wound layers. In practice, the curved frame parts very often geometrically form sections of a torus. In this work, the difficulty of achieving a uniform winding of toroidal parts is described and quantified. It is shown that attaining the required winding quality depends significantly on the geometrical parameters of the torus in question. A mathematical model with a detailed procedure describing how to determine the number of rovings of a given width on toroidal parts is presented. The results of this work are illustrated with practical examples of today's industrial problems.
RESUMEN
The extraordinary features of fibrous composites enable advanced industries to design composite structures with superior performance compared to traditional structures. Composite frame structures have been designed frequently as components of mechanical systems to resist lateral and gravity loads. The manufacturing of high-quality composite frames depends primarily on the accurate fiber winding on frames with different pro-files and curved shapes. The optimal fiber winding process on a nonbearing composite frame with a circular cross-section is described in previous works by the same authors. As an extension to that, this study focuses on the manufacturing of straight-line composite frames with different profile radii at multiple locations. Such production procedure allows continuous winding of fibers gradually on individual parts of the frame and generally with different angles of fiber winding. The winding procedure is performed using fiber-processing head and industrial robot. The procedure for calculating the distance of the winding plane of fibers on the frame from the guide-line of the fiber-processing head is targeted. This distance depends on the required angle of fiber winding, the radius of the frame, and the geometric parameters of the fiber-processing head. The coordination of the speed of winding the fibers on the frame and the speed of the passage of the frame through the winding head is also considered. Determining the correct distance of winding the fibers from the corresponding guide-line of fiber-processing head and right coordination of the winding speed and the speed of passage of the frame through the fiber-processing head ensure compliance of the required angles of fiber windings on the frame and homogeneity of winding fibers, which are the two of the most important prerequisites for producing a quality composite frame. The derived theory is well verified on a practical experimental example.
RESUMEN
Polymer composite frame has been frequently used in the main structural body of vehicles in aerospace, automotive, etc., applications. Manufacturing of complex curved composite frame suffer from the lack of accurate and optimum method of winding process that lead to preparation of uniform fiber arrangement in critical location of the curved frame. This article deals with the fabrication of high-quality polymer composite frame through an optimal winding of textile fibers onto a non-bearing core frame using a fiber-processing head and an industrial robot. The number of winding layers of fibers and their winding angles are determined based on the operational load on the composite structure. Ensuring the correct winding angles and thus also the homogeneity of fibers in each winding layer can be achieved by using an industrial robot and by definition of its suitable off-line trajectory for the production cycle. Determination of an optimal off-line trajectory of the end-effector of a robot (robot-end-effector (REE)) is important especially in the case of complicated 3D shaped frames. The authors developed their own calculation procedure to determine the optimal REE trajectory in the composite manufacturing process. A mathematical model of the winding process, matrix calculus (particularly matrices of rotations and translations) and an optimization differential evolution algorithm are used during calculation of the optimal REE trajectory. Polymer composites with greater resistance to failure damage (especially against physical destruction) can be produced using the above mentioned procedure. The procedure was successfully tested in an experimental composite laboratory. Two practical examples of optimal trajectory calculation are included in the article. The described optimization algorithm of REE trajectory is completely independent of the industrial robot type and robot software tools used and can also be used in other composite manufacturing technologies.
