Inherently Smart Laminates of Carbon Fibers in a Polymer Matrix

1996 ◽  
Vol 434 ◽  
Author(s):  
Xiaojun W Ang ◽  
D. D. L. Chung
Keyword(s):  
Carbon Fibers ◽  
Electrical Resistance ◽  
Fracture Stress ◽  
Maximum Stress ◽  
Fatigue Testing ◽  
Dynamic Strain ◽  
Matrix Composites ◽  
Fiber Breakage ◽  
Cyclic Tension ◽  
Carbon Fiber Epoxy

AbstractReal-time monitoring of fatigue damage and dynamic strain in inherently smart andcontinuous unidirectional (0° and 90°) and bidirectional (0°/90°) carbon fiber epoxy-matrix composites by electrical resistance (R) measurement was achieved. Upon cyclic tension (0°) of 0° or 0°/90° composites, R (0°) decreased reversibly, while R perpendicular to the fiber layers increased reversibly, though R in both directions changed irreversibly by a small amount after the first cycle. Upon fatigue testing of the 0° composite at a maximum stress of 57–58% of the fracture stress, the peak R (0°) in a cycle irreversibly increased both in spurts and continuously, due to fiber breakage, which started at 30% of the fatigue life. For the 90° composite, R(0°) increased reversibly upon tension (0°) and decreased reversibly upon compression (0°).

Fiber Breakage In Polymer-Matrix Composites During Static And Fatigue Loading, Observed By Electrical Resistance Measurement

1997 ◽  
Vol 503 ◽  
Author(s):  
Xiaojun Wang ◽  
D. D. L. Chung
Keyword(s):  
Electrical Resistance ◽  
Fatigue Testing ◽  
Polymer Matrix Composites ◽  
Fatigue Loading ◽  
Fiber Direction ◽  
Matrix Composites ◽  
Fiber Breakage ◽  
Static Tensile Loading ◽  
Static Tensile ◽  
Epoxy Matrix Composite

ABSTRACTBy measuring the electrical resistance of a continuous unidirectional carbon fiber epoxy-matrix composite along the fiber direction during loading in this direction, fiber breakage was progressively monitored in real time. Fiber breakage occurred in spurts involving 1000 fibers or more. It started at about half of the failure strain during static tensile loading and at about half of the fatigue life during tensiontension fatigue testing. Immediately before static failure, 35% of the fibers were broken. Immediately before fatigue failure, 18% of the fibers were broken. The fiber breakage was accompanied by decrease in modulus.

Fiber breakage in polymer-matrix composite during static and fatigue loading, observed by electrical resistance measurement

1999 ◽  
Vol 14 (11) ◽  
pp. 4224-4229 ◽  
Author(s):  
Xiaojun Wang ◽  
D. D. L. Chung
Keyword(s):  
Matrix Composite ◽  
Electrical Resistance ◽  
Fatigue Testing ◽  
Fatigue Loading ◽  
Fiber Direction ◽  
Fiber Breakage ◽  
Static Tensile Loading ◽  
Static Tensile ◽  
Epoxy Matrix Composite ◽  
Carbon Fiber Epoxy

By measuring the electrical resistance of a continuous unidirectional carbon fiber epoxy-matrix composite along the fiber direction during loading in this direction, fiber breakage was progressively monitored in real time. Fiber breakage occurred in spurts involving 1000 or more fibers. It started at about half of the failure strain during static tensile loading and at about half of the fatigue life during tension–tension fatigue testing. Immediately before static failure, at least 35% of the fibers were broken. Immediately before fatigue failure, at least 18% of the fibers were broken. The fiber breakage was accompanied by decrease in modulus.

Cumulative acoustic emission energy for damage detection in composites reinforced by carbon fibers within low-cycle fatigue regime at various displacement amplitudes and rates

2021 ◽  
pp. 096739112098570
Author(s):  
Mohammad Azadi ◽  
Mohsen Alizadeh ◽  
Seyed Mohammad Jafari ◽  
Amin Farrokhabadi
Keyword(s):  
Acoustic Emission ◽  
Carbon Fibers ◽  
Polymer Matrix Composites ◽  
Low Cycle Fatigue ◽  
Energy Parameter ◽  
Fatigue Tests ◽  
Matrix Cracking ◽  
Matrix Composites ◽  
Cycle Fatigue ◽  
Cumulative Energy

In the present article, acoustic emission signals were utilized to predict the damage in polymer matrix composites, reinforced by carbon fibers, in the low-cycle fatigue regime. Displacement-controlled fatigue tests were performed on open-hole samples, under different conditions, at various displacement amplitudes of 5.5, 6.0, 6.5 and 7.0 mm and also under various displacement rates of 25, 50, 100 and 200 mm/min. After acquiring acoustic emission signals during cycles, two characteristic parameters were used, including the energy and the cumulative energy. Obtained results implied that the energy parameter of acoustic emission signals could be used only for the macroscopic damage, occurring at more than 65% of normalized fatigue cycles under different test conditions. However, the cumulative energy could properly predict both microscopic and macroscopic defects, at least two failure types, including matrix cracking at first cycles and the fiber breakage at last cycles. Besides, scanning electron microscopy images proved initially such claims under all loading conditions.

Graphene oxide modified carbon fiber reinforced epoxy composites

2020 ◽  
Vol 40 (5) ◽  
pp. 415-420 ◽  
Author(s):  
Yasin Altin ◽  
Hazal Yilmaz ◽  
Omer Faruk Unsal ◽  
Ayse Celik Bedeloglu
Keyword(s):  
Graphene Oxide ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Spray Coating ◽  
Sem Analysis ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Quick Method ◽  
Carbon Fiber Reinforced

AbstractThe interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.

Electrical Resistance and Acoustic Emission During Fatigue Testing of Pristine and High Velocity Impact SiC/SiC Composites at Room and Elevated Temperature

2016 ◽  
Author(s):  
Zipeng Han ◽  
Gregory N. Morscher ◽  
Emmanuel Maillet ◽  
Manigandan Kannan ◽  
Sung R. Choi ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Acoustic Emission ◽  
Cyclic Loading ◽  
Electrical Resistance ◽  
Fatigue Testing ◽  
Early Stage ◽  
Loading Conditions ◽  
Initial Attempt ◽  
Matrix Cracks ◽  
Sic Composites

Electrical resistance (ER) is a relatively new approach for real-time monitoring and evaluating damage in SiC/SiC composites for a variety of loading conditions. In this study, ER of woven silicon carbide fiber-reinforced silicon carbide composite systems in their pristine and impacted state were measured under cyclic loading conditions at room and high temperature (1200C). In addition, modal acoustic emission (AE) was also monitored, which can reveal the occasion of matrix cracks and fiber. ER measurement and AE technique are shown in this study to be useful methods to monitor damage and indicate the failure under cyclic loading. Based on the slope of the ER evolution, an initial attempt has been made to develop a method allowing a critical damage phase to be identified. While the physical meaning of the critical point is not yet clear, it has the potential to allow the failure to be indicated at its early stage.

Carbon Fiber Reinforced Cement and Mortar

1990 ◽  
Vol 211 ◽  
Author(s):  
J. R. Linton ◽  
P. L. Berneburg ◽  
E. M. Gartner ◽  
A. Bentur
Keyword(s):  
Carbon Fibers ◽  
Fiber Length ◽  
Length Distribution ◽  
Fiber Breakage ◽  
Image Analysis Technique ◽  
Analysis Technique ◽  
Reinforcing Fibers ◽  
Before And After ◽  
Reinforced Cement ◽  
Critical Fiber Length

AbstractAlthough carbon fibers have high tensile strengths and are chemically inert, their application in cementitious composites is limited due to their brittleness. An image analysis technique employed to determine the length distribution of the reinforcing fibers before and after mixing in cement paste and mortar matrices indicates that substantial fiber breakage occurs during mixing. In paste mixtures, the average fiber length after mixing remains above the critical fiber length, but in mortar mixes the average fiber length falls below the critical fiber length resulting in no significant enhancement of composite flexural properties.

Production and mechanical characterization of Ni-coated carbon fibers reinforced Al-6063 alloy matrix composites

2019 ◽  
Vol 787 ◽  
pp. 543-550 ◽  
Author(s):  
Anıl Alten ◽  
Eray Erzi ◽  
Özen Gürsoy ◽  
Gökçe Hapçı Ağaoğlu ◽  
Derya Dispinar ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Mechanical Characterization ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Coated Carbon
Sign in / Sign up

Export Citation Format

Share Document