Tow-drop areas influence on composite laminates in automated fiber placement
Topic(s) : Manufacturing
Co-authors :
Félix THÉBAULT (FRANCE), Alexandre CLÉMENT (FRANCE), Sylvain FRÉOUR , Pascal CASARI (FRANCE)Abstract :
Automated processes for composite structures are becoming a major development axis as many industries invest in them. With the increasing use of composite materials, industrial companies are now faced with the challenge of optimizing automated manufacturing techniques to increase product quality and machine throughput. Automated fiber placement (AFP) is a highly effective and versatile method. However, the increasing complexity of part designs presents new challenges for fiber placement in terms of the strength and durability of the structural parts produced.
AFP machines layup multiple narrow flat tows of composite prepreg tapes that are individually cut to conform and fit to the designed shape. The parts produced can be complex due to double curvature or angular constraints designed to solve stress concentration problems. The combination of different sources of complexity during manufacture leads to defects such as tow drops, overlaps, resin-rich pockets and unexpected bridging [1]. These defects in turn create localized heterogeneous areas that can weaken the overall strength of the laminate.
Current research on defects considers them to be localized artefacts [2,3] and tow drops areas created by the surface covering methods [4]. The main objective of this work is to present a review of the literature to help us in the following stages of the study.
This paper discusses the effects of programmed fiber path discontinuities that result in tow drops in the finished laminate. During the manufacture of double-curved parts, tow steering and angular deviation are induced up to a point where the limits of the manufacturing process are reached. The tows are cut as soon as the manufacturing limits are reached. A new tow must then be laid with respect to the steering and orientation constraints, and because of its change in direction, it will collide with its neighbors. At these boundaries, defects appear where tows of different angles collide, creating either gaps or overlaps, depending on the coverage parameters used [4]. The size and shape of these defects is defined by the angle of incidence and the width of the tows.
Based on this review, the purpose of this study is to analyze the influence of this type of defect on the tensile, compressive and in-plane shear strength of parts manufactured by AFP. To this end, finite element method modelling is used to simulate the local in-plane and flexural behavior of planar laminates with embedded tow-drop artificial defects. Different configurations are tested by incorporating relevant defects as described in the literature.
AFP machines layup multiple narrow flat tows of composite prepreg tapes that are individually cut to conform and fit to the designed shape. The parts produced can be complex due to double curvature or angular constraints designed to solve stress concentration problems. The combination of different sources of complexity during manufacture leads to defects such as tow drops, overlaps, resin-rich pockets and unexpected bridging [1]. These defects in turn create localized heterogeneous areas that can weaken the overall strength of the laminate.
Current research on defects considers them to be localized artefacts [2,3] and tow drops areas created by the surface covering methods [4]. The main objective of this work is to present a review of the literature to help us in the following stages of the study.
This paper discusses the effects of programmed fiber path discontinuities that result in tow drops in the finished laminate. During the manufacture of double-curved parts, tow steering and angular deviation are induced up to a point where the limits of the manufacturing process are reached. The tows are cut as soon as the manufacturing limits are reached. A new tow must then be laid with respect to the steering and orientation constraints, and because of its change in direction, it will collide with its neighbors. At these boundaries, defects appear where tows of different angles collide, creating either gaps or overlaps, depending on the coverage parameters used [4]. The size and shape of these defects is defined by the angle of incidence and the width of the tows.
Based on this review, the purpose of this study is to analyze the influence of this type of defect on the tensile, compressive and in-plane shear strength of parts manufactured by AFP. To this end, finite element method modelling is used to simulate the local in-plane and flexural behavior of planar laminates with embedded tow-drop artificial defects. Different configurations are tested by incorporating relevant defects as described in the literature.