Defect layer method to capture effect of gaps and overlaps in variable stiffness laminates made by Automated Fiber Placement

Automated manufacturing defects are new types of composite structure defects induced during fiber deposition by robots. Fiber tow gap is one of the most probable types of defects observed in the Automated Fiber Placement (AFP) technique. This defect can affect the structural integrity of structures by reducing structural strength and stiffness. The effect of this defect on the mechanical response of the composite laminates has been investigated experimentally in the literature. However, there is still no efficient numerical/analytical method for damage assessment of composite structures with distributed induced gaps manufactured by the AFP technique. The present paper aims to develop the Induced Defect Layer Method (IDLM), a new robust meso-macro model for damage analysis of the composite laminates with gaps. In this method, a geometrical parameter, Gap Percentage (GP), is implemented to incorporate the effect of induced-gaps in the elastic, inelastic, and softening behavior at the material points. Thus, while the plasticity and failure of the resin pockets in conjunction with intralaminar composite damages can be evaluated by this method, the defective areas are not required to be defined as resin elements in the Finite Element (FE) models. It can also be applied for any arbitrary distributions of the defects in the multi-layer composite structures, making it a powerful tool for continuum damage analysis of large composite structures. Results indicate that the proposed method can consider the effect of gaps in both elastic and inelastic behavior of the composite laminate with defects. It also provides good agreement with the experimental results.

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Defect Characteristics and Online Detection Techniques During Manufacturing of FRPs Using Automated Fiber Placement: A Review

Polymers ◽

10.3390/polym12061337 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1337 ◽

Cited By ~ 2

Author(s):

Shouzheng Sun ◽

Zhenyu Han ◽

Hongya Fu ◽

Hongyu Jin ◽

Jaspreet Singh Dhupia ◽

...

Keyword(s):

Mechanical Properties ◽

Large Scale ◽

Variable Stiffness ◽

Future Research ◽

Online Detection ◽

Manufacturing Defects ◽

Manufacturing Method ◽

Detection Techniques ◽

Fiber Placement ◽

Automated Fiber Placement

Automated fiber placement (AFP) is an advanced manufacturing method for composites, which is especially suitable for large-scale composite components. However, some manufacturing defects inevitably appear in the AFP process, which can affect the mechanical properties of composites. This work aims to investigate the recent works on manufacturing defects and their online detection techniques during the AFP process. The main content focuses on the position defect in conventional and variable stiffness laminates, the relationship between the defects and the mechanical properties, defect control methods, the modeling method for a void defect, and online detection techniques. Following that, the contributions and limitations of the current studies are discussed. Finally, the prospects of future research concerning theoretical and practical engineering applications are pointed out.

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Optimization of variable stiffness composites with embedded defects induced by Automated Fiber Placement

Composite Structures ◽

10.1016/j.compstruct.2013.07.059 ◽

2014 ◽

Vol 107 ◽

pp. 160-166 ◽

Cited By ~ 74

Author(s):

Mahdi Arian Nik ◽

Kazem Fayazbakhsh ◽

Damiano Pasini ◽

Larry Lessard

Keyword(s):

Variable Stiffness ◽

Fiber Placement ◽

Automated Fiber Placement

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Size-dependent behavior of laminates with curvilinear fibers made by automated fiber placement

Science and Engineering of Composite Materials ◽

10.1515/secm-2014-0167 ◽

2015 ◽

Vol 22 (2) ◽

pp. 157-163 ◽

Cited By ~ 2

Author(s):

Mahdi Arian Nik ◽

Larry Lessard ◽

Damiano Pasini

Keyword(s):

Variable Stiffness ◽

Buckling Load ◽

Fiber Placement ◽

Plate Size ◽

Load Increase ◽

Automated Fiber Placement ◽

Fiber Path ◽

Turning Radius ◽

Curvilinear Fibers ◽

Minimum Turning Radius

AbstractVariable stiffness laminates can be manufactured using curvilinear fiber paths. A curvilinear fiber path is generally defined based on the plate size and has a curvature that is dependent on the plate size. In practice, however, the fiber path must satisfy manufacturing constraints, such as the minimum turning radius imposed by the automated fiber placement machine, thereby limiting the possible amount of fiber steering. In this work, we studied the effect of the plate size on the structural properties of a plate manufactured with curvilinear fibers. We considered four plate sizes, which were designed by a constant curvature fiber path. We optimized the plates for both maximum buckling load and in-plane stiffness. The results showed that the in-plane stiffness of the plate was not controlled by the plate size, whereas the buckling load was highly affected by the curvature of the fiber path. Hence, the potential of a buckling load increase reduced for plate sizes smaller than the minimum turning radius. In addition, for a given maximum curvature of the fiber path, the influence of a complex layup on the buckling load was marginal.

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Overlap-Stiffened Panels for Optimized Buckling Performance Under Minimum Steering Radius Constraints

10.31224/osf.io/xpvn4 ◽

2020 ◽

Author(s):

Raphael Ummels ◽

Saullo G. P. Castro

Keyword(s):

Design Method ◽

Variable Stiffness ◽

Radius Of Curvature ◽

Stiffened Panels ◽

Fiber Placement ◽

Design Variables ◽

Automated Fiber Placement ◽

Circular Fiber ◽

Straight Fiber ◽

Radius Constraint

Recent research on variable stiffness laminates have shown both numerically and experimentally that further improvement on the buckling behaviour is possible by incorporating overlaps that result in variable thickness profiles, with the thickness non-linearly coupled with the local steering angle. We present the concept of overlap-stiffened panels, developing a design method that allows for incorporating higher-stiffness regions into individual plies of a variable-angle tow (VAT) laminate, taking advantage of the non-linear coupling between the tow steering angles and the local thickness. The proposed method naturally copes with minimum steering radius constraints of different manufacturing processes, and the present study considers two tow steering processes: automated fiber placement (AFP) and continuous tow shearing (CTS). The minimum radius constraint is satisfied by connecting two transition regions of thickness specified on each ply by means of circular fiber tow arcs, of which the radius of curvature always exceed the minimum manufacturing constraint. Each individual ply exploring the overlap-stiffened design is described using 5 design variables. Laminates made up of these overlap-stiffened plies are optimized for a maximum volume-normalized buckling performance under bi-axial compression, measured through FEM, by a genetic algorithm and benchmarked against a straight fiber panel optimized for the same load case. The conclusion can be drawn that both AFP and CTS overlap-stiffened VAT panels can at least achieve the double of the volume-normalized buckling performance of an optimized straight fiber panel, demonstrating the potential of the proposed design method.

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Optimization of Variable Stiffness Composites in Automated Fiber Placement Process using Evolutionary Algorithms

Procedia CIRP ◽

10.1016/j.procir.2017.03.302 ◽

2017 ◽

Vol 66 ◽

pp. 79-84 ◽

Cited By ~ 7

Author(s):

Vahid Ghaffari Mejlej ◽

Paul Falkenberg ◽

Eiko Türck ◽

Thomas Vietor

Keyword(s):

Evolutionary Algorithms ◽

Variable Stiffness ◽

Fiber Placement ◽

Automated Fiber Placement

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The effect of the percentage of steered plies on the bending-induced buckling performance of a variable stiffness composite cylinder

Science and Engineering of Composite Materials ◽

10.1515/secm-2014-0258 ◽

2015 ◽

Vol 22 (2) ◽

pp. 149-156 ◽

Cited By ~ 8

Author(s):

Mohammad Rouhi ◽

Hossein Ghayoor ◽

Suong V. Hoa ◽

Mehdi Hojjati

Keyword(s):

Performance Improvement ◽

Design Procedure ◽

Laminated Composite ◽

Variable Stiffness ◽

Design Parameters ◽

Composite Cylinder ◽

Element Analysis ◽

Fiber Placement ◽

Structural Improvement ◽

Automated Fiber Placement

AbstractThe fiber steering capability of automated fiber placement machines offers the designers more room to fully exploit the directional properties of composite materials. Circumferential stiffness tailoring by fiber steering can considerably increase the bending-induced buckling performance of laminated composite cylinders. The potential structural improvement resulting from fiber steering depends on different design parameters such as the number of plies considered for fiber steering in a laminate. In this study, the buckling performance improvement of a variable stiffness (VS) composite cylinder is investigated for different percentages of plies considered for fiber steering in a multilayered composite laminate. A surrogate-based modeling along with a multi-step optimization is used in the design procedure of this study. The improvements in the buckling performance are shown and verified using finite element analysis in ABAQUS software. The mechanisms leading to buckling performance improvement of VS composites are also investigated and presented for different percentages of fiber-steered plies.

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Automated Fiber Placement of Composite Wind Tunnel Blades: Process Planning and Manufacturing

10.33599/nasampe/s.19.1538 ◽

2019 ◽

Cited By ~ 1

Author(s):

Ramy Harik ◽

Joshua Halbritter ◽

Dawn Jegley ◽

Ray Grenoble ◽

Brian Mason

Keyword(s):

Wind Tunnel ◽

Process Planning ◽

Fiber Placement ◽

Automated Fiber Placement

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In Situ Impregnation of Continuous Thermoplastic Composite Prepreg for Additive Manufacturing and Automated Fiber Placement

Composites Part A Applied Science and Manufacturing ◽

10.1016/j.compositesa.2021.106446 ◽

2021 ◽

pp. 106446

Author(s):

James Garofalo ◽

Daniel Walczyk

Keyword(s):

Additive Manufacturing ◽

Thermoplastic Composite ◽

Fiber Placement ◽

Automated Fiber Placement

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Review: Filament Winding and Automated Fiber Placement with In Situ Consolidation for Fiber Reinforced Thermoplastic Polymer Composites

Polymers ◽

10.3390/polym13121951 ◽

2021 ◽

Vol 13 (12) ◽

pp. 1951

Author(s):

Yi Di Boon ◽

Sunil Chandrakant Joshi ◽

Somen Kumar Bhudolia

Keyword(s):

Processing Parameters ◽

Filament Winding ◽

Reference Points ◽

Thermoplastic Composites ◽

Manufacturing Processes ◽

Fiber Reinforced ◽

Consolidation Process ◽

Fiber Placement ◽

Automated Fiber Placement

Fiber reinforced thermoplastic composites are gaining popularity in many industries due to their short consolidation cycles, among other advantages over thermoset-based composites. Computer aided manufacturing processes, such as filament winding and automated fiber placement, have been used conventionally for thermoset-based composites. The automated processes can be adapted to include in situ consolidation for the fabrication of thermoplastic-based composites. In this paper, a detailed literature review on the factors affecting the in situ consolidation process is presented. The models used to study the various aspects of the in situ consolidation process are discussed. The processing parameters that gave good consolidation results in past studies are compiled and highlighted. The parameters can be used as reference points for future studies to further improve the automated manufacturing processes.

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