Fracture analysis of a single polyacrylonitrile-based carbon fiber in rigid-fixing and flexible-fixing chopping processes

2016 ◽  
Vol 87 (12) ◽  
pp. 1435-1444 ◽  
Author(s):  
Longsheng Lu ◽  
Zhaorui Hou ◽  
Feixiang Zhang ◽  
Yingxi Xie ◽  
Yong Tang
Keyword(s):  
Carbon Fiber ◽  
Cutting Forces ◽  
Failure Surface ◽  
Fracture Analysis ◽  
Fiber Fracture ◽  
Short Carbon Fiber ◽  
Bending Effect ◽  
Short Carbon ◽  
Bending Angles

Chopping is an efficient way to produce short carbon fiber (CF). Generally, there are two types of fixing constraints available in the chopping process: rigid-fixing and flexible-fixing. Simplified experiments were performed using glass and rubber as the fixing constraints in cutting a single polyacrylonitrile-based CF to reveal the influence of the fixing constraints in CF chopping. The cutting forces and the bending angles with different fixing constraints were analyzed. Furthermore, the failure surface of the CF was observed. Due to an additional bending effect in the flexible-fixing cutting, the failure surface of the CF was rough, and the cutting-off force was approximately 5% of the force in rigid-fixing cutting. Therefore, flexible-fixing cutting is a suitable way to decrease the cutting-off force in CF chopping. Moreover, it was concluded that the fiber fracture in rigid-fixing cutting is caused by compression, whereas in flexible-fixing cutting, it results from bending. We hope our work is beneficial to the design of the chopping procedure for short CF.

scholarly journals Effect of Geometric Parameters and Moisture Content on the Mechanical Performances of 3D-Printed Isogrid Structures in Short Carbon Fiber-Reinforced Polyamide

2021 ◽  
Author(s):  
Valerio Di Pompeo ◽  
Archimede Forcellese ◽  
Tommaso Mancia ◽  
Michela Simoncini ◽  
Alessio Vita
Keyword(s):  
Carbon Fiber ◽  
Moisture Content ◽  
Geometric Parameters ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Short Carbon Fiber ◽  
3D Printed ◽  
Carbon Fiber Reinforced ◽  
Mechanical Performances ◽  
Short Carbon

AbstractThe present paper aims at studying the effect of geometric parameters and moisture content on the mechanical performances of 3D-printed isogrid structures in short carbon fiber-reinforced polyamide (namely Carbon PA). Four different geometric isogrid configurations were manufactured, both in the undried and dried condition. The dried isogrid structures were obtained by removing the moisture from the samples through a heating at 120 °C for 4 h. To measure the quantity of removed moisture, samples were weighted before and after the drying process. Tensile tests on standard specimens and buckling tests on isogrid panels were performed. Undried samples were tested immediately after 3D printing. It was observed that the dried samples are characterized by both Young modulus and ultimate tensile strength values higher than those provided by the undried samples. Similar results were obtained by the compression tests since, for a given geometric isogrid configuration, an increase in the maximum load of the dried structure was detected as compared to the undried one. Such discrepancy tends to increase as the structure with the lowest thickness value investigated is considered. Finally, scanning electron microscopy was carried out in order to analyze the fractured samples and to obtain high magnification three-dimensional topography of fractured surfaces after testing.

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