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

2015 ◽  
Vol 22 (2) ◽  
pp. 157-163 ◽  
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.

scholarly journals Optimizing Variable-Axial Fiber-Reinforced Composite Laminates: The Direct Fiber Path Optimization Concept

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Lars Bittrich ◽  
Axel Spickenheuer ◽  
José Humberto S. Almeida ◽  
Sascha Müller ◽  
Lothar Kroll ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Variable Stiffness ◽  
Tensile Specimen ◽  
Path Optimization ◽  
Fiber Reinforced ◽  
Simulation And Optimization ◽  
Fiber Placement ◽  
Fiber Path ◽  
Curvilinear Fibers ◽  
Novel Concept

The concept of aligning reinforcing fibers in arbitrary directions offers a new perception of exploiting the anisotropic characteristic of the carbon fiber-reinforced polymer (CFRP) composites. Complementary to the design concept of multiaxial composites, a laminate reinforced with curvilinear fibers is called variable-axial (also known as variable stiffness and variable angle tow). The Tailored Fiber Placement (TFP) technology is well capable of manufacturing textile preforming with a variable-axial fiber design by using adapted embroidery machines. This work introduces a novel concept for simulation and optimization of curvilinear fiber-reinforced composites, where the novelty relies on the local optimization of both fiber angle and intrinsic thickness build-up concomitantly. This framework is called Direct Fiber Path Optimization (DFPO). Besides the description of DFPO, its capabilities are exemplified by optimizing a CFRP open-hole tensile specimen. Key results show a clear improvement compared to the current often used approach of applying principal stress trajectories for a variable-axial reinforcement pattern.

Enhancement of Static and Dynamic Performance of Composite Tapered Pretwisted Rotating Blade With Variable Stiffness

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Touraj Farsadi
Keyword(s):  
Performance Metrics ◽  
Dynamic Performance ◽  
Variable Stiffness ◽  
Coupling Factor ◽  
Element Analysis ◽  
Structural Part ◽  
Fiber Placement ◽  
Thin Walled ◽  
Fiber Path ◽  
Curvilinear Fibers

Abstract Composite pretwisted tapered rotating thin-walled beams (TWB) can be used as a load-carrying structural part of a composite helicopter, wind turbine, fan, and turbomachinery blades. In the present study, the variable stiffness concept with curvilinear fiber path is used to achieve improved structural statics and dynamics performance of uniform and asymmetric composite thin-walled rotating beams. A parametric study is performed to investigate the effect of different fiber paths on the structural performance metrics including frequency spacing, coupling factor, and critical buckling load. For this purpose, The Euler–Lagrange governing equations of the dynamic system are derived via Hamilton's principle. To solve the governing set of equations, the extended Galerkin’s method (EGM) is employed. To validate the TWB model with curvilinear fibers, commercial finite element analysis tools abaqus is used. The author believes that the results presented here are likely to provide valuable information to the engineers involved in the design of advanced turbomachinery rotating blades using a variable stiffness concept with curvilinear fiber placement.

Improvement of structural characteristics of composite thin-walled beams using variable stiffness concept via curvilinear fiber placement

2021 ◽  
pp. 095441002098824
Author(s):  
Touraj Farsadi ◽  
Mirac Onur Bozkurt ◽  
Demirkan Coker ◽  
Altan Kayran
Keyword(s):  
Performance Metrics ◽  
Structural Characteristics ◽  
Variable Stiffness ◽  
Structural Performance ◽  
Fe Method ◽  
Fiber Placement ◽  
Thin Walled ◽  
Fiber Path ◽  
Curvilinear Fibers ◽  
Straight Fiber

This study presents the use of variable stiffness concept via curvilinear fiber placement to achieve improved structural characteristics in composite thin-walled beams (TWBs). The TWB used in the study is constructed in circumferentially asymmetric stiffness (CAS) configuration. The variation of fiber angles along the span and the width of the TWB is included by defining two fiber path functions. A parametric study is performed to investigate the effects of different fiber paths on the structural performance metrics including frequency spacing, unit twist, and critical buckling load. For this purpose, a semi-analytical solution method is developed to conduct free vibration, deformation, and buckling analyses of the TWB with curvilinear fibers. The semi-analytical method is validated with several finite element (FE) analyses performed using ABAQUS. Elastic stress analyses of TWBs with selected fiber paths subjected to simplified distributed loading are also conducted using the FE method, and a ply failure criterion is applied to evaluate the strength of these TWBs. Overall results show that curvilinear fiber placement varied along the span leads to greater structural performance for a composite TWB than the straight fiber configuration.

scholarly journals Experimental Investigation on the Influence of Fiber Path Curvature on the Mechanical Properties of Composites

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2602
Author(s):  
Huaqiao Wang ◽  
Jihong Chen ◽  
Zhichao Fan ◽  
Jun Xiao ◽  
Xianfeng Wang
Keyword(s):  
Tensile Strength ◽  
Path Planning ◽  
Composite Laminates ◽  
Bending Strength ◽  
High Strength ◽  
Bending Test ◽  
Fiber Placement ◽  
Automated Fiber Placement ◽  
Fiber Path ◽  
Path Curvature

Automated fiber placement (AFP) has been widely used as an advanced manufacturing technology for large and complex composite parts and the trajectory planning of the laying path is the primary task of AFP technology. Proposed in this paper is an experimental study on the effect of several different path planning placements on the mechanical behavior of laminated materials. The prepreg selected for the experiment was high-strength toughened epoxy resin T300 carbon fiber prepreg UH3033-150. The composite laminates with variable angles were prepared by an eight-tow seven-axis linkage laying machine. After the curing process, the composite laminates were conducted by tensile and bending test separately. The test results show that there exists an optimal planning path among these for which the tensile strength of the laminated specimens decreases slightly by only 3.889%, while the bending strength increases greatly by 16.68%. It can be found that for the specific planning path placement, the bending strength of the composite laminates is significantly improved regardless of the little difference in tensile strength, which shows the importance of path planning and this may be used as a guideline for future AFP process.

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

2014 ◽  
Vol 107 ◽  
pp. 160-166 ◽  
Author(s):  
Mahdi Arian Nik ◽  
Kazem Fayazbakhsh ◽  
Damiano Pasini ◽  
Larry Lessard
Keyword(s):  
Variable Stiffness ◽  
Fiber Placement ◽  
Automated Fiber Placement

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

2013 ◽  
Vol 97 ◽  
pp. 245-251 ◽  
Author(s):  
Kazem Fayazbakhsh ◽  
Mahdi Arian Nik ◽  
Damiano Pasini ◽  
Larry Lessard
Keyword(s):  
Variable Stiffness ◽  
Defect Layer ◽  
Capture Effect ◽  
Fiber Placement ◽  
Layer Method ◽  
Automated Fiber Placement

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

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.

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

Procedia CIRP ◽  
2017 ◽  
Vol 66 ◽  
pp. 79-84 ◽  
Author(s):  
Vahid Ghaffari Mejlej ◽  
Paul Falkenberg ◽  
Eiko Türck ◽  
Thomas Vietor
Keyword(s):  
Evolutionary Algorithms ◽  
Variable Stiffness ◽  
Fiber Placement ◽  
Automated Fiber Placement

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

2015 ◽  
Vol 22 (2) ◽  
pp. 149-156 ◽  
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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