Characterization of fatigue behavior of long fiber reinforced thermoplastic (LFT) composites

In order to optimize resource efficiency, glass fiber-reinforced polymers (GFRP) have been implemented in recent years in a wide range of applications of transport industries. In this context, GFR-epoxy (GFR-EP) is currently being used mainly because of their sufficiently investigated properties and production processes. Polyurethane (PU), however, shows advantages in terms of energy efficiency and damage tolerance. The aim of this study is the characterization of the fatigue behavior of GFR-PU by stepwise exploration of damage development on microscopic level. Therefore, multiple amplitude and constant amplitude tests have been carried out. Hysteresis and temperature measurements were applied in order to investigate the damage processes and correlated with in situ computed tomography (CT) in intermitting tests. The damage development and mechanisms could be characterized and separated. The results confirm known GFRP damage characteristics, whereas also material-specific peculiarities regarding crack development could be revealed.

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Characterization of Long-Term Creep–Fatigue Behavior for Glass Fiber–Reinforced Polypropylene

Plastics Engineering - Handbook of Polypropylene and Polypropylene Composites, Revised and Expanded ◽

10.1201/9780203911808.ch13 ◽

2003 ◽

Cited By ~ 1

Author(s):

Les Campbell

Keyword(s):

Glass Fiber ◽

Fatigue Behavior ◽

Fiber Reinforced ◽

Glass Fiber Reinforced ◽

Creep Fatigue ◽

Term Creep

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TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105758 ◽

1988 ◽

Vol 46 ◽

pp. 738-739

Author(s):

G. Das ◽

R. E. Omlor

Keyword(s):

Titanium Alloys ◽

Reaction Zone ◽

Carbon Layer ◽

Fiber Reinforced ◽

Reaction Products ◽

Sic Fibers ◽

Sic Fiber ◽

The Matrix ◽

Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

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Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154755 ◽

1989 ◽

Vol 47 ◽

pp. 556-557

Author(s):

K.L. More ◽

R.A. Lowden

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Chemical Vapor ◽

Chemical Vapor Infiltration ◽

Frictional Stress ◽

Fiber Reinforced ◽

Pull Out ◽

Carbon Coated ◽

Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

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