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.

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.

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.

Design and Manufacturing of Variable Angle Tow Laminate

2016 ◽  
Vol 674 ◽  
pp. 59-64 ◽  
Author(s):  
Anti Haavajõe ◽  
Madis Mikola ◽  
Meelis Pohlak
Keyword(s):  
Surface Roughness ◽  
Composite Structure ◽  
Variable Stiffness ◽  
Pneumatic Cylinder ◽  
Fiber Reinforced ◽  
Strength Performance ◽  
Analysis And Design ◽  
Fiber Placement ◽  
Variable Angle ◽  
Compaction Force

Variable angle tow (VAT) laminates have shown enhanced stiffness/strength performance compared to conventional straight fiber laminates. Employment of VAT allows utilizing variable stiffness design of composite structure, thus it widens the design possibilities. As a result, composite structure with improved mechanical characteristics can be manufactured. The main aims of the current study are to give an overview on methods and algorithms used for analysis and design of VAT laminates, and to develop technology and equipment for manufacturing laminate with improved structural performance. In order to improve the accuracy of the compaction process, a set of experiments were carried out using a simple testing device. For measuring the compaction force, a pneumatic cylinder, pressure regulator and digital manometer were used. The temperature of the consolidation area and the heat distribution were screened with the thermal camera. Infrared heater was used as a heating source. Material used in the experiment was carbon fiber reinforced polyamide.Findings show that in addition to the main parameters – the compaction force and temperature, there are many minor factors, such as the compaction wheel diameter, material and surface roughness of the compaction roller, the material and surface roughness of the mold and the pretension in the laminating tape and also the laminating speed, all influence the quality of the final product.Key words: Advanced Fiber Placement Technology, Automated Fiber Placement, Automated Tape Laying, Fiber Reinforced Composites, Laminates

scholarly journals Multi-Objective Optimization of Variable-Stiffness Composites Fabricated by Tailored Fiber Placement Machine

2019 ◽  
Vol 2 (1) ◽  
pp. 14-18
Author(s):  
Shinya Honda
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Variable Stiffness ◽  
Optimization Method ◽  
Pareto Optimum ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Fiber Placement ◽  
Curvilinear Fibers ◽  
Placement Machine

A multi-objective optimization method for the laminated composite fabricated by a tailored fiber placement machine that is an application of embroidering machine is presented. The mechanical properties of composite with curvilinear fibers including stiffness, volume fraction, and density are variable depending on curvatures of fibers. The present study first measures the relation between curvatures and mechanical properties. The measured results indicate that the stiffness of composite decreases linearly as the curvature increases. Then, the obtained relation is applied to the multi-objective optimization where the maximum principal strain and magnitude of curvature are employed as objective functions. Obtained Pareto optimum solutions are widely distributed ranging from the solutions with curvilinear fibers to those with straight fibers, and the curvilinear fiber has still advantages over straight fiber even its weakened stiffness.

scholarly journals Tailored Fiber Placement in Thermoplastic Composites

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Axel Spickenheuer ◽  
Christina Scheffler ◽  
Lars Bittrich ◽  
Rico Haase ◽  
Dieter Weise ◽  
...  
Keyword(s):  
Fiber Composite ◽  
Low Cost ◽  
Optimization Methods ◽  
Path Optimization ◽  
Thermoplastic Composites ◽  
Fiber Placement ◽  
Whole Process ◽  
First Results ◽  
Incremental Sheet Metal Forming ◽  
Fiber Path

Fiber path optimization methods combined with the Tailor Fiber Placement (TFP) technology provide the optimum correlation between load case and fiber orientation and therefore lead to unmatched component performance with endless fiber composite materials. The aim of this work is the development of an innovative manufacturing technology for thermoplastic composites (TPC) including sizing-adapted commingled glass fiber (GF) / thermoplastic yarns (SpinCom yarns) to be processed by TFP to textile preforms with a variable-axial, load adapted fiber design. Furthermore, these preforms will be consolidated in a low energy and resource consuming process using novel light and low cost forming tools produced by incremental sheet metal forming technology. Finally, a low cost solution for thermal processing even for complex shaped TPC parts will be presented. Heading towards optimized resource and cost efficiency of the whole process chain, first results of SpinCom yarns, fiber path optimization, tool manufacturing and forming procedure are presented and demonstrated using GF/PBT (polybutylene therephthalate) SpinCom yarns and the geometry of a bicycle saddle.

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