scholarly journals Influence of Embedded Gap and Overlap Fiber Placement Defects on Interlaminar Properties of High Performance Composites

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5332
Author(s):  
Denis Cartié ◽  
Marine Lan ◽  
Peter Davies ◽  
Christophe Baley
Keyword(s):  
High Performance ◽  
Crack Arrest ◽  
Shear Loading ◽  
Plane Shear ◽  
Manufacturing Defects ◽  
Fiber Placement ◽  
Out Of Plane ◽  
Beam Shear ◽  
Automated Fiber Placement ◽  
Interlaminar Shear

Automated fiber placement (AFP), once limited to aerospace, is gaining acceptance and offers great potential for marine structures. This paper describes the influence of manufacturing defects, gaps, and overlaps, on the out-of-plane properties of carbon/epoxy composites manufactured by AFP. Apparent interlaminar shear strength measured by short beam shear tests was not affected by the presence of defects. However, the defects do affect delamination propagation. Under Mode I (tension) loading a small crack arrest effect is noted, resulting in higher apparent fracture energies, particularly for specimens manufactured using a caul plate. Under Mode II (in-plane shear) loading there is a more significant effect with increased fracture resistance, as stable propagation for specimens with small gaps changes to arrest with unstable propagation for larger gaps.

scholarly journals Analysis of Elastic Medium with Nonconcentric Two Circular Inclusions under Out-of-Plane Shear Loading.

1998 ◽  
Vol 64 (618) ◽  
pp. 438-444 ◽  
Author(s):  
Kenichi HIRASHIMA ◽  
Shigerou NAKANE ◽  
Mutsumi MIYAGAWA ◽  
Shinji KIKUCHI
Keyword(s):  
Elastic Medium ◽  
Shear Loading ◽  
Plane Shear ◽  
Out Of Plane

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

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1337 ◽  
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.

scholarly journals Multiscale Collaborative Optimization of Processing Parameters for Carbon Fiber/Epoxy Laminates Fabricated by High-Speed Automated Fiber Placement

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Zhenyu Han ◽  
Shouzheng Sun ◽  
Zhongxi Shao ◽  
Hongya Fu
Keyword(s):  
Mechanical Properties ◽  
Strain Energy ◽  
High Speed ◽  
Processing Parameters ◽  
Collaborative Optimization ◽  
Manufacturing Defects ◽  
Fiber Placement ◽  
Automated Fiber Placement ◽  
Processing Optimization ◽  
Carbon Fiber Epoxy

Processing optimization is an important means to inhibit manufacturing defects efficiently. However, processing optimization used by experiments or macroscopic theories in high-speed automated fiber placement (AFP) suffers from some restrictions, because multiscale effect of laying tows and their manufacturing defects could not be considered. In this paper, processing parameters, including compaction force, laying speed, and preheating temperature, are optimized by multiscale collaborative optimization in AFP process. Firstly, rational model between cracks and strain energy is revealed in order that the formative possibility of cracks could be assessed by using strain energy or its density. Following that, an antisequential hierarchical multiscale collaborative optimization method is presented to resolve multiscale effect of structure and mechanical properties for laying tows or cracks in high-speed automated fiber placement process. According to the above method and taking carbon fiber/epoxy tow as an example, multiscale mechanical properties of laying tow under different processing parameters are investigated through simulation, which includes recoverable strain energy (ALLSE) of macroscale, strain energy density (SED) of mesoscale, and interface absorbability and matrix fluidity of microscale. Finally, response surface method (RSM) is used to optimize the processing parameters. Two groups of processing parameters, which have higher desirability, are obtained to achieve the purpose of multiscale collaborative optimization.

Experimental and theoretical investigation of mixed mode I/III brittle fracture of U-notched polystyrene components

2017 ◽  
Vol 53 (1) ◽  
pp. 15-25 ◽  
Author(s):  
A.R. Torabi ◽  
Behnam Saboori
Keyword(s):  
Brittle Fracture ◽  
Mixed Mode ◽  
General Purpose ◽  
Shear Loading ◽  
Mode I ◽  
Mean Stress ◽  
Plane Shear ◽  
Out Of Plane ◽  
Notch Tip ◽  
Stress Criteria

Brittle fracture of components made of the general-purpose polystyrene and weakened by an edge U-notch under combined tension/out-of-plane shear loading conditions (mixed mode I/III) has not been studied yet experimentally or theoretically. In this research, a recently developed loading fixture is employed for experimentally investigating the fracture of U-notched general-purpose polystyrene samples with various notch tip radii of 0.5, 1, 2 and 4 mm when they are subjected to different combinations of tension/out-of-plane shear. The samples are fabricated with four different notch tip radii with the purpose of assessing the influence of this geometrical parameter. The experimental values of fracture load and out-of-plane fracture angle are theoretically predicted by the two stress-based criteria of point stress and mean stress lately extended to general loading case of mixed mode I/II/III. It is shown that both the point stress and mean stress criteria provide acceptable predictions to fracture behavior of U-notched general-purpose polystyrene specimens. The critical distances needed for the point stress and mean stress criteria are determined based on the experimental results of the U-notched samples tested under pure mode I loading. No meaningful difference is found between the fracture loads and fracture initiation angles predicted by the point stress and mean stress criteria. It is also observed that as the mode III contribution in the applied mixed mode I/III loading increases, a larger total external load is needed for the fracture of U-notched general-purpose polystyrene specimens to occur.

scholarly journals Bonding between high-performance polymer processed by Fused Filament Fabrication and PEEK/carbon fiber laminate

2021 ◽  
Author(s):  
Isciane Caprais ◽  
Pierre Joyot ◽  
Emmanuel Duc ◽  
Simon Deseur
Keyword(s):  
Additive Manufacturing ◽  
Composite Structures ◽  
Composite Laminate ◽  
High Performance ◽  
Processing Conditions ◽  
Fused Filament Fabrication ◽  
Fiber Placement ◽  
High Performance Polymer ◽  
Automated Fiber Placement ◽  
The Impact

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.

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

2019 ◽  
Vol 3 (2) ◽  
pp. 56 ◽  
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.

Characterization of piercing damage in CFRP cross-ply laminates after punch shear machining via impact loading

2021 ◽  
pp. 002199832110316
Author(s):  
Shinya Matsuda ◽  
Kohei Mabe ◽  
Keiji Ogi ◽  
Shigeki Yashiro ◽  
Yoshifumi Kakudo
Keyword(s):  
Shear Deformation ◽  
Composite Structures ◽  
Polymer Matrix Composites ◽  
Shear Loading ◽  
Matrix Composites ◽  
Plane Shear ◽  
Reinforced Plastic ◽  
Out Of Plane ◽  
Machining Operations

In industrial processes, piercing and trimming are essential because composite structures are usually manufactured in a near-net shape to reduce machining operations. Punching and shear cutting using out-of-plane shear loading are expected to increase productivity. Nevertheless, little is known about the effects of such operations on polymer-matrix composites. This study presents on the characterization of piercing damage in typical carbon fiber reinforced plastic (CFRP) cross-ply laminates [0°2/90°2]s after punching using quasi-static (QS) and drop-weight impact (DWI) loadings. During QS punching, the upper and lower ply interfaces delaminate due to the high shear stress to cut fibers and gradual shear deformation in the middle ply; however, during DWI punching at a low impact velocity, delamination of the lower ply interface can be reduced due to the localization of shear deformation, as compared to that in QS punching. Finally, the damage accumulation process during DWI punching is discussed.

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