Optical measurement of voids in situ during infusion of carbon reinforcements

2020 ◽  
pp. 002199832095982
Author(s):  
C Lystrup ◽  
A George ◽  
B Zobell ◽  
K Boster ◽  
C Childs ◽  
...  
Keyword(s):  
Image Analysis ◽  
Carbon Fiber ◽  
High Performance ◽  
Optical Measurement ◽  
Void Formation ◽  
Digital Camera ◽  
Void Content ◽  
Liquid Composite Molding ◽  
Automated Method

Liquid composite molding (LCM) is growing in importance as an alternative to traditional prepreg-autoclave methods for manufacture high-performance composites. The most significant roadblock to industry’s implementation of LCM is the usually higher void content compared with prepreg processing. One tool for reducing void levels in LCM involves optimization of flow velocity, which requires models to be developed to describe void formation at a given velocity. To help solve this problem, the following research illustrates the first known method for optical void measurement in situ during infusion in a carbon fiber reinforcement. Similar to previous studies on glass fiber, this work utilizes fluorescent dye and a digital camera to produce sufficient contrast and resolution for image analysis. Visible bubbles are photographed against the opaque carbon fiber background. An automated method of image analysis is outlined, which was used to analyze 230 images for three different flow orientations of a single fabric, producing the highest amount of experimental data seen so far on in situ void measurement. The resulting data identifies a minimum velocity threshold for minimal macro-void formation. The resultant void characterization framework will better enable optimization of LCM processing for high-performance composites based on carbon reinforcements.

Optical Measurement of Preform Impregnation in Resin Transfer Molding

1993 ◽  
Vol 305 ◽  
Author(s):  
Thomas Nowak ◽  
Jung-Hoon Chun
Keyword(s):  
High Performance ◽  
Optical Measurement ◽  
Resin Transfer Molding ◽  
Void Formation ◽  
Woven Fabric ◽  
Void Content ◽  
Trade Off ◽  
Transfer Molding ◽  
Scale Models ◽  
Visualization Experiments

AbstractInfiltration of preforms used to manufacture high-performance, advanced polymer composites can lead to void formation due to inhomogeneities within the preforms. Void formation occurs at three distinct length scales: the fiber, tow and part scales. Flow visualization experiments were used to characterize void formation at the tow and fiber scales. Effects of tow-scale inhomogeneities were studied by varying the warp angle of a woven fabric. Effects of fiber-scale inhomogeneities were studied using scale models of typical tows. The experiments indicate that minimization of void content requires a trade-off between fiberscale and tow-scale void formation.

Postprocessing method-induced mechanical properties of carbon fiber-reinforced thermoplastic composites

2020 ◽  
pp. 089270572094537
Author(s):  
Van-Tho Hoang ◽  
Bo-Seong Kwon ◽  
Jung-Won Sung ◽  
Hyeon-Seok Choe ◽  
Se-Woon Oh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Processing Parameters ◽  
Thermoplastic Composites ◽  
Void Content ◽  
Fiber Reinforced ◽  
Crystallinity Degree ◽  
Automated Fiber Placement ◽  
Carbon Fiber Reinforced

Promising carbon fiber-reinforced thermoplastic (CF/polyetherketoneketone (PEKK)) composites were fabricated by the state-of-the-art technology known as “Automated Fiber Placement.” The mechanical properties of CF/PEKK were evaluated for four different postprocessing methods: in situ consolidation, annealing, vacuum bag only (VBO), and hot press (HP). The evaluation was performed by narrowing down the relevant processing parameters (temperature and layup speed). Furthermore, the void content and crystallinity of CF/PEKK were measured to determine the effect of these postprocessing processes. The HP process resulted in the best quality with the highest interlaminar shear strength, highest crystallinity degree, and lowest void content. The second most effective method was VBO, and annealing also realized an improvement compared with in situ consolidation. The correlation between the postprocessing method and the void content and crystallinity degree was also discussed.

Facile in situ preparation of high-performance epoxy vitrimer from renewable resources and its application in nondestructive recyclable carbon fiber composite

2019 ◽  
Vol 21 (6) ◽  
pp. 1484-1497 ◽  
Author(s):  
Sheng Wang ◽  
Songqi Ma ◽  
Qiong Li ◽  
Xiwei Xu ◽  
Binbo Wang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Renewable Resources ◽  
High Performance ◽  
Fiber Composite ◽  
Fiber Composites ◽  
Carbon Fiber Composites ◽  
Carbon Fiber Composite ◽  
In Situ Preparation

A high-performance epoxy vitrimer was facilely prepared from a renewable lignin derivative vanillin, and its carbon-fiber composites were nondestructively recycled.

Carbon fiber paper@MgO films: in situ fabrication and high-performance removal capacity for phosphate anions

2018 ◽  
Vol 25 (34) ◽  
pp. 34788-34792 ◽  
Author(s):  
Saeed Ahmed ◽  
Muhammad Naeem Ashiq ◽  
Dianqing Li ◽  
Pinggui Tang ◽  
Yongjun Feng
Keyword(s):  
Carbon Fiber ◽  
High Performance ◽  
Removal Capacity ◽  
In Situ Fabrication ◽  
Carbon Fiber Paper ◽  
Phosphate Anions

Preparation of carbon fiber-reinforced polyimide composites via in situ induction heating

2016 ◽  
Vol 29 (9) ◽  
pp. 1027-1036 ◽  
Author(s):  
Chang Wei Liu ◽  
Chun Yan Qu ◽  
Lei Han ◽  
De Zhi Wang ◽  
Wan Bao Xiao ◽  
...  
Keyword(s):  
High Temperature ◽  
Carbon Fiber ◽  
Induction Heating ◽  
High Performance ◽  
Thermoplastic Composites ◽  
Heating Process ◽  
Current Field ◽  
Heating Method ◽  
Polyimide Composites

Induction heating, a direct and contactless heating method, is generally more rapid and energetically more efficient than other heating methods used. In this work, we report the high-temperature imidization of carbon fiber/polyimide (PI) composites using an in situ induction heating method. Furthermore, we compare the advantages of the method to a conventional thermal procedure. The formed composites feature almost identical imidization rates, glass transition temperatures, and thermal oxidative stabilities cured at the same heating temperatures using a different heating process. Upon doping with ferriferous oxide, the ability of the magnetic nanoparticles in an alternating current field was studied to further drive the heating process and increase the rising and cooling time. The in situ induction heating process proves to be a powerful method for the high-temperature polymerization of high-performance thermoplastic composites, particularly for a PI matrix.

scholarly journals Annealing Effects on the Crystallinity of Carbon Fiber-Reinforced Polyetheretherketone and Polyohenylene Laminate Composites Manufactured by Laser Automatic Tape Placement

2020 ◽  
Vol 26 (3) ◽  
pp. 308-316
Author(s):  
Svetlana RISTESKA ◽  
Anka T. PETKOSKA ◽  
Samoil SAMAK ◽  
Marian DRIENOVSKY
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Processing Parameters ◽  
Polyphenylene Sulfide ◽  
Thermoplastic Composites ◽  
Void Content ◽  
Angle Of Incidence ◽  
Annealing Step

In situ consolidation of thermoplastic composites by Automated Tape Placement (ATP) is challenging. High quality ATP grade pre-preg material and tape head equipped with an efficient heat sources like lasers offer an opportunity towards high deposition rates and improved mechanical properties of composite materials. In this study uni-directional carbon fiber/ polyphenylene sulfide (UD tape prepreg CF/PPS), carbon fiber/polyetheretherketone (UD tape prepreg CF/PEEK) as well as blend of carbon fiber/polyetheretherketone/polyphenylene sulfide (UD tapes prepregs CF/PEEK/PPS) laminates are compared in terms of their properties after beeing processed by ATP technology. CF/PPS, CF/PEEK and blend CF/PPS/PEEK laminate specimens were processed using in-situ laser-assisted ATP (LATP) process. LATP processing parameters used in this study were chosen based on a preliminary trials; the results provide a basis for refinement of these parameters and prepreg material with an optimal and balanced set of final mechanical properties. This study showed an attempt how to manage the processing parameters for LATP process and to obtain composite materials with tailored properties. The process for production of thermoplastic plates with LATP head in general is a process that is governed by many parameters such as: laser power, angle of incidence, roller pressure and temperature, placement speed, tool temperature, then types of the roller material and the tool material. These parameters are not subject of discussing in this paper; they are kept constant, and the goal of the paper is to manage the crystallinity level within the composite thermoplastic material during annealing step at different temperatures after LATP process. Also, the void content during the production process could be controlled. More particularly, the authors showed that composites based on PPS matrix manufactured with LATP process possess higher flexural strength, with less void content compared to samples based on PEEK matrix. These samples showed also higher crystallinity after annealing step.

scholarly journals Hybridization of Hemp Fiber and Recycled-Carbon Fiber in Polypropylene Composites

2019 ◽  
Vol 11 (11) ◽  
pp. 3163 ◽  
Author(s):  
Niyati Shah ◽  
Joseph Fehrenbach ◽  
Chad A. Ulven
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
High Performance ◽  
Cannabis Sativa ◽  
Natural Fiber ◽  
Void Content ◽  
Fiber Reinforced ◽  
Micro Computed Tomography ◽  
Hemp Fiber ◽  
Polypropylene Composites

In recent years there has been a substantial growth in the use of natural fiber reinforced composite in more advanced applications. However, high strength applications require high mechanical properties. Hybridization of natural fibers with synthetic fibers is an effective method of increasing the field of application and mechanical properties. The effects of hybridizing hemp (Cannabis sativa L.) fiber with recycled-carbon fiber were investigated in this study to determine the trends in mechanical properties resulting from varied weight fractions. Characterization of void content was accomplished using micro computed tomography (micro-CT). Through hybridizing hemp fiber and recycled carbon fiber in a polypropylene thermoplastic, a new class of high performance, low cost composites were demonstrated for injection molding applications. This study showcased a 10–15% increase in tensile strength after the reinforcement of recycled-carbon fiber with hemp fiber. A 30–35% increase was observed in the flexure strength after the reinforcement of recycled-carbon fiber with hemp fiber. Impact strength also had an increase of 35–40% for hemp fiber reinforced recycled-carbon fiber polypropylene composites.

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