Study of integral hat-stiffened composite structures manufactured by automated fiber placement and co-curing process

Automated fiber placement processes could be combined with additive manufacturing to produce more functionally complex composite structures with more flexibility. The challenge is to add functions or reinforcements to PEEK/carbon composite parts manufactured by automated fiber placement process, with additive manufacturing by fused filament fabrication. This consists of extruding a molten polymer through a nozzle to create a 3D part. Bonding between polymer filaments is a thermally driven phenomenon and determines the integrity and the final mechanical strength of the printed part. 3d-printing high performance polymers is still very challenging because they involve high thermal gradients during the process. The purpose of this work is to find a process window where the bonding strength is maximized between the composite laminate and the first layer of printed polymer, and inside the printed function as well. Experimental measurements of the temperature profiles at the interface between a composite substrate and 3d-printed PEI under different processing conditions were carried out. The interface was observed using microscopic sections. The methodology for studying the impact of printing parameters on the cohesion and adhesion of printed parts with a composite laminate is described. This work provides insights about the influence of processing conditions on the bond formation between high-performance polymer surfaces. It highlights the importance of controlling the thermal history of the materials all along the process.

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Manufacturing-Induced Imperfections in Composite Parts Manufactured via Automated Fiber Placement

Journal of Composites Science ◽

10.3390/jcs3020056 ◽

2019 ◽

Vol 3 (2) ◽

pp. 56 ◽

Cited By ~ 7

Author(s):

Falk Heinecke ◽

Christian Willberg

Keyword(s):

Composite Structures ◽

Review Paper ◽

State Of The Art ◽

Fiber Composite ◽

Research Gaps ◽

Manufacturing Defects ◽

Cycle Times ◽

Fiber Placement ◽

Simulation Based ◽

Automated Fiber Placement

The automated fiber placement process (AFP) enables the manufacturing of large and geometrical complex fiber composite structures with high quality at low cycle times. Although the AFP process is highly accurate and reproducible, manufacturing induced imperfections in the produced composite structure occur. This review summarizes and classifies typical AFP-related manufacturing defects. Several methodologies for evaluating the effects of such manufacturing defects from the literature are reviewed. This review paper presents recent scientific contributions and discusses proposed experimental and simulation-based methodologies. Among the identified ten defect classes, gaps and overlaps are predominant. This paper focuses then on methods for modelling and assessing gaps and overlaps. The state of the art in modelling gaps and overlaps and assessing their influence on mechanical properties is presented. Finally, research gaps and remaining issues are identified.

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Effect of automated fiber placement (AFP) manufacturing signature on mechanical performance of composite structures

Composite Structures ◽

10.1016/j.compstruct.2019.111335 ◽

2019 ◽

Vol 228 ◽

pp. 111335 ◽

Cited By ~ 11

Author(s):

Minh Hoang Nguyen ◽

Avinkrishnan A. Vijayachandran ◽

Paul Davidson ◽

Damon Call ◽

Dongyeon Lee ◽

...

Keyword(s):

Composite Structures ◽

Mechanical Performance ◽

Fiber Placement ◽

Automated Fiber Placement

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Fuzzy-Adaptive PID Based Tow Tension Controller for Robotic Automated Fiber Placement

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.643.48 ◽

2014 ◽

Vol 643 ◽

pp. 48-53 ◽

Cited By ~ 1

Author(s):

Jie Chen ◽

Wen Jun Xu ◽

Ben Wang ◽

Yu Gang Duan ◽

Xiao Hui Zhang

Keyword(s):

Fuzzy Logic ◽

Steady State ◽

Working Conditions ◽

Pid Control ◽

Composite Structures ◽

Cost Effective ◽

Fiber Placement ◽

Automated Fiber Placement ◽

Adaptive Pid Control ◽

Fuzzy Adaptive

Robotic automated fiber placement (Robotic AFP) was a cost-effective and highly innovative approach to produce large and complex composite structures. In order to achieve desired qualities, the tow tension of the process required to becontrolled accurately. Due to the high nonlinearity of the system, such as the large elastic modulus, flexibility and viscosity of the tow, traditional methods failed to work effectively. A fuzzy-adaptive PIDcontroller combining fuzzy logic and adaptive PID together was proposed in this work. Fuzzy logic was able to respond quickly to disturbances without the need for an accurate model and adaptive PID control could eliminate the steady-state error by adapting its parameters to the working conditions. With this method, the tow tension could be precisely regulated thus improved the qualities of the composite structures.

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Induced defect layer method to characterize the effect of fiber tow gaps for the laminates manufactured by automated fiber placement technique

Journal of Composite Materials ◽

10.1177/00219983211031649 ◽

2021 ◽

pp. 002199832110316

Author(s):

Mohammadhossein Ghayour ◽

Mehdi Hojjati ◽

Rajamohan Ganesan

Keyword(s):

Composite Laminates ◽

Composite Structures ◽

Structural Integrity ◽

Mechanical Response ◽

Defect Layer ◽

Damage Analysis ◽

Manufacturing Defects ◽

Fiber Placement ◽

Layer Method ◽

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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A Novel Approach: Combination of Automated Fiber Placement (AFP) and Additive Layer Manufacturing (ALM)

Journal of Composites Science ◽

10.3390/jcs2030042 ◽

2018 ◽

Vol 2 (3) ◽

pp. 42 ◽

Cited By ~ 4

Author(s):

Mohammad Rakhshbahar ◽

Michael Sinapius

Keyword(s):

Mechanical Properties ◽

Composite Structures ◽

Fiber Composite ◽

Gap Effect ◽

Fiber Placement ◽

Reinforced Plastics ◽

Novel Approach ◽

Automated Fiber Placement ◽

Automated Processing ◽

Processing Techniques

Automated processing techniques such as automated fiber placement (AFP) or automated tape laying (ATL) are well known nowadays. However, there is still a lot of potential for these methods to achieve better results, especially for large and complex composite structures. In this experimental work, the gap effect with the Automated Fiber Placement is shown and a solution to overcome this drawback is presented. The gaps are particularly apparent on complex and/or double-curved surfaces and reduce the mechanical properties of the composite structure. In order to cover the unavoidable weak area of this effect, a plurality of fiber composite layers are laid on top of one another in order to increase the mechanical properties of components. This in turn makes the components heavier and more expensive to produce. In this new method, the gaps are detected by profile sensor after placement of the tape on the mold. The gaps are filled with the aid of a 3D printer with carbon continuous-fiber reinforced plastics. By combining the 3D printing and AFP technology, composite parts can be manufactured in a more homogeneous manner. Subsequently, the components are produced faster, cheaper and even lighter because of the avoidance of the additional layers.

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Experimental and numerical investigation on the open-hole compressive strength of AFP composites containing gaps and overlaps

Journal of Composite Materials ◽

10.1177/0021998317690917 ◽

2017 ◽

Vol 51 (26) ◽

pp. 3631-3646 ◽

Cited By ~ 6

Author(s):

Aymen Marouene ◽

Pierre Legay ◽

Rachid Boukhili

Keyword(s):

Compression Strength ◽

Composite Laminates ◽

Composite Structures ◽

Progressive Failure ◽

Experimental Tests ◽

Consolidation Process ◽

Fiber Placement ◽

Positive Effects ◽

Open Hole ◽

Automated Fiber Placement

Laminated composite structures manufactured via the automated fiber placement process inherently contain process defects know as gaps and overlaps. These defects raise concerns when they are located on or near holes intended for mechanical fastening. This investigation attempts to predict the effect of automated fiber placement-generated defects on the open-hole compression strength by combining both experimental tests and numerical simulation. Tested open-hole compression specimens containing gaps and overlaps oriented at 0° or 90° and centered on or shifted near the hole show that, depending on their location, the gaps and overlaps may have negative, negligible, or positive effects on the open-hole compression strength. The better than expected effects are compatible with microscopic observations that clearly show the rearrangement of the plies during the consolidation process, which prevent the formation of deleterious discontinuities. Incorporating these observations in a numerical model, which simulates gaps and overlaps embedded inside the composite laminates, and applying a progressive failure analysis, confirms that the effects of automated fiber placement defects depend as much on their type as on their location relative to the hole center. Finally, the results obtained from a parametric study provided further explanation on the effects of automated fiber placement defects on the failure strength of perforated composite laminates.

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