Stresses in coated fiber-reinforced composites with interface flaw

1994 ◽  
Vol 66 (4) ◽  
pp. R67-R72
Author(s):  
Han Xueli ◽  
Wang Duo
Keyword(s):  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Coated Fiber

scholarly journals Hi-Nicalon fiber-reinforced celsian matrix composites: Influence of interface modification

1998 ◽  
Vol 13 (6) ◽  
pp. 1530-1537 ◽  
Author(s):  
Narottam P. Bansal ◽  
Jeffrey I. Eldridge
Keyword(s):  
Fiber Strength ◽  
Mechanical Damage ◽  
Young Modulus ◽  
Matrix Cracking ◽  
Fiber Reinforced Composites ◽  
Matrix Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Coated Fiber ◽  
Point Bend

Unidirectional celsian matrix composites having 42–45 vol% of uncoated or BN-SiC coated Hi-Nicalon fibers were tested in three-point bend at room temperature. The uncoated fiber-reinforced composites showed catastrophic failure with strength of 210 ± 35 MPa and a flat fracture surface. In contrast, composites reinforced with coated fibers exhibited graceful failure with extensive fiber pullout. Values of first matrix cracking stress and strain were 435 ± 35 MPa and 0.27 ± 0.01%, respectively, with ultimate strength as high as 960 MPa. The elastic Young modulus of the uncoated and coated fiber-reinforced composites were 184 ± 4 GPa and 165 ± 5 GPa, respectively. Fiber push-through tests and microscopic examination indicated no chemical reaction at the uncoated or coated fiber-matrix interface. The low strength of composite with uncoated fibers is due to degradation of the fiber strength from mechanical damage during processing. Because both the coated- and uncoated-fiber-reinforced composites exhibited weak interfaces, the beneficial effect of the BN-SiC dual layer is primarily the protection of fibers from mechanical damage during processing.

scholarly journals Copper and Nickel Coating of Carbon Fiber for Thermally and Electrically Conductive Fiber Reinforced Composites

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 823 ◽  
Author(s):  
Simon Bard ◽  
Florian Schönl ◽  
Martin Demleitner ◽  
Volker Altstädt
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Carbon Fibers ◽  
Fiber Reinforced Composites ◽  
Lightning Strike ◽  
Fiber Direction ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Coated Fiber

In this paper, the thermal and electrical conductivity and mechanical properties of fiber reinforced composites produced from nickel- and copper-coated carbon fibers compared to uncoated fibers are presented. The carbon fibers were processed by our prepreg line and cured to laminates. In the fiber direction, the thermal conductivity doubled from ~3 W/mK for the uncoated fiber, to ~6 W/mK for the nickel, and increased six times to ~20 W/mK for the copper-coated fiber for a fiber volume content of ~50 vol %. Transverse to the fiber, the thermal conductivity increased from 0.6 W/mK (uncoated fiber) to 0.9 W/mK (nickel) and 2.9 W/mK (copper) at the same fiber content. In addition, the electrical conductivity could be enhanced to up to ~1500 S/m with the use of the nickel-coated fiber. We showed that the flexural strength and modulus were in the range of the uncoated fibers, which offers the possibility to use them for lightning strike protection, for heatsinks in electronics or other structural heat transfer elements.

High Temperature Mechanical Property of Al2O3 Coated Quartz-Fiber Reinforced Methyl Silicon Resin Composites

2007 ◽  
Vol 351 ◽  
pp. 135-141 ◽  
Author(s):  
Lei Wang ◽  
Yu Dong Huang ◽  
Li Liu
Keyword(s):  
High Temperature ◽  
Flexural Strength ◽  
Fiber Reinforced Composites ◽  
Processing Temperature ◽  
Resin Composites ◽  
Reinforced Composites ◽  
Quartz Fiber ◽  
Fiber Reinforced ◽  
Coated Fiber ◽  
Silicon Resin

In the present work, Al2O3 was coated on the quartz fiber by the sol-gel method to improve the high temperature mechanical properties of the quartz fiber/methyl silicon resin composites. The X-ray diffraction results showed that the crystalline property of the Al2O3 coating increased with the processing temperature. Before 500oC treated, the Al2O3 coated fiber reinforced composites have lower flexural strength than the commercial fiber reinforced one. While after 500oC treated, the flexural strength of Al2O3 coated fiber reinforced composites was higher than the uncoated reinforced one. And the flexural strength for the 400oC treated Al2O3 coated fiber reinforced composites was higher than that of the 600oC treated one. The mechanism of the crack propagation in the purchased and Al2O3 coated fiber reinforced composites was also studied through scanning electronic microscopy (SEM).

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