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.

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°).

Low Cycle Fatigue of Unidirectional Glass/Epoxy Composites

1999 ◽  
Author(s):  
V. M. Harik ◽  
J. R. Klinger ◽  
B. K. Fink ◽  
T. A. Bogetti ◽  
A. Paesano ◽  
...  
Keyword(s):  
Polymer Matrix Composites ◽  
Low Cycle Fatigue ◽  
Glass Fibers ◽  
Fatigue Loading ◽  
Large Strains ◽  
Matrix Composites ◽  
Cycle Fatigue ◽  
Degradation Rates ◽  
Characteristics Analysis ◽  
Stress Ratios

Abstract Low cycle fatigue (LCF) behavior of unidirectional polymer matrix composites (PMCs) reinforced with glass fibers is investigated. LCF conditions involve high loads reaching up to 90% of the material ultimate strength. LCF characterization of PMCs is carried out under tension-tension fatigue loading to identify the key physical phenomena occurring in PMCs under LCF conditions and to determine their unique characteristics. Analysis of experimental data indicates that finite strain rates, large strains and stress ratios may affect LCF behavior of PMC structures and the property degradation rates.

Fracture Mechanisms in Fiber Reinforced Polymer Matrix Composites

2014 ◽  
Vol 1611 ◽  
pp. 153-158
Author(s):  
C. Rodríguez ◽  
M. Hinojosa ◽  
J. Aldaco ◽  
A. Cázares
Keyword(s):  
Carbon Fibers ◽  
Matrix Composite ◽  
Polymer Matrix ◽  
Epoxy Matrix ◽  
Polymer Matrix Composites ◽  
Glass Fibers ◽  
Fracture Mechanisms ◽  
Matrix Composites ◽  
Polyester Matrix ◽  
Epoxy Matrix Composite

ABSTRACTIn this work we report the fractographic study of polymer matrix composites specimens reinforced with glass and carbon fibers. Specimens of a polyester matrix composite with 30% of E-glass fibers are prepared and fractured in flexure mode. We also test an epoxy matrix composite with 30% carbon fibers, which is fractured in flexure mode. All specimens are manufactured based on the D790 ASTM standard for bending mode at room temperature. As an exception, the composites with epoxy matrix and reinforced with carbon fiber are cured in an autoclave. The most commonly observed fracture mechanisms are debonding in the interphase, delamination, Chevron lines, microbuckling, river patterns and radial fracture on the fibers.

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