Stress-Strain Response in SiC/SiC Composites under Cyclic Loading

2007 ◽  
Vol 353-358 ◽  
pp. 1406-1409 ◽  
Author(s):  
Jun Ji Ohgi ◽  
S. Tanaka ◽  
T. Kuramoto ◽  
M. Suzuki ◽  
Koichi Goda
Keyword(s):  
Cyclic Loading ◽  
Interfacial Strength ◽  
Maximum Load ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Fracture Load ◽  
Stress Strain ◽  
Pull Out ◽  
Fiber Matrix ◽  
Sic Composites

The tension-tension fatigue tests for SiC/SiC composites were performed under the conditions that the maximum load Pmax was 80-90% to the fracture load of the tensile tests and the stress ratio was Rσ = 0.5. The composites exhibited a width in stress-strain hysteresis loop under one load cycling. In some cases the mean strain εmean gradually increase with increasing in number of cycles. These variations would reflect the developments of the fatigue damage at the fiber/matrix interface during the cyclic loading process. The pull-out lengths of the fibers for the fatigued- and not fatigued-specimens were measured through the SEM observations after the tensile test. In all materials, the average pull-out length of fibers in fatigued material was larger than in not fatigued material because the cyclic loading affected on the fiber/matrix interfacial strength.

Experimental Investigation on 2D and 3D Braided C/SiC Composites

2006 ◽  
Vol 326-328 ◽  
pp. 1685-1688 ◽  
Author(s):  
Bo Wang ◽  
Gui Qiong Jiao ◽  
Yan Jun Chang ◽  
Wen Ge Pan
Keyword(s):  
Acoustic Emission ◽  
Room Temperature ◽  
Tensile Tests ◽  
Damage Evaluation ◽  
Stress Strain ◽  
Pull Out ◽  
Sic Composites ◽  
2D And 3D ◽  
Zigzag Shape ◽  
Ae Counts

Tensile tests of two-dimensionally braided C/SiC composites and three-dimensionally braided C/SiC composites had been carried out at room temperature. Some specimens had been unloaded during experiments. Acoustic Emission signals also had been collected during experiments. The following conclusions were arrived. The stress-strain curves of these two materials were of nonlinear characters, and there were no obvious linear segments on those curves. Failure characters of these two materials were different: There appeared ply pull-out for 2D braided C/SiC specimens and there appeared zigzag shape for 3D braided C/SiC specimens. Stress-strain curves of loading-unloading tests and Acoustic Emission signals of those two materials showed damage evaluation during tests. There were different AE counts and AE energy characters between two materials.

scholarly journals Low- and High-Cycle Fatigue Behavior of FRCM Composites

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5412
Author(s):  
Angelo Savio Calabrese ◽  
Tommaso D’Antino ◽  
Pierluigi Colombi ◽  
Carlo Poggi
Keyword(s):  
Cyclic Loading ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Curve ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Static Tensile

This paper describes methods, procedures, and results of cyclic loading tensile tests of a PBO FRCM composite. The main objective of the research is the evaluation of the effect of low- and high-cycle fatigue on the composite tensile properties, namely the tensile strength, ultimate tensile strain, and slope of the stress–strain curve. To this end, low- and high-cycle fatigue tests and post-fatigue tests were performed to study the composite behavior when subjected to cyclic loading and after being subjected to a different number of cycles. The results showed that the mean stress and amplitude of fatigue cycles affect the specimen behavior and mode of failure. In high-cycle fatigue tests, failure occurred due to progressive fiber filaments rupture. In low-cycle fatigue, the stress–strain response and failure mode were similar to those observed in quasi-static tensile tests. The results obtained provide important information on the fatigue behavior of PBO FRCM coupons, showing the need for further studies to better understand the behavior of existing concrete and masonry members strengthened with FRCM composites and subjected to cyclic loading.

scholarly journals Fatigue in Fiber-Metal Laminates for Small Wind Turbine Blades Application

2018 ◽  
Vol 165 ◽  
pp. 07005
Author(s):  
Wei Sai ◽  
Gin Boay Chai
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Maximum Load ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Wind Condition ◽  
Wind Turbine Blades ◽  
Operation Condition ◽  
Small Wind Turbine ◽  
Fiber Metal

A methodology to study the fatigue of a wind turbine blade in a 10KW small wind turbine is proposed in this paper. Two working conditions (namely normal fatigue operation condition and extreme wind condition) are considered based on IEC61400-2. The maximum load calculated from both cases were used as a reference to perform material sample fatigue study. Fiber-metal laminate – GLARE 3/2 with a centre 1mm notch on the external aluminium layers was modelled based on fracture mechanics approach to calculate the stress intensity factor and fatigue crack growth rate at maximum applied stress of 240Mpa. GLARE panel fabrication and tensile tests were included. The fatigue tests were performed on unnotched samples with stress range from 80Mpa to 300Mpa and plotted into S-N curve.

Cyclic pull-out test of single PVA fibers in cementitious matrix

2011 ◽  
Vol 45 (26) ◽  
pp. 2765-2772 ◽  
Author(s):  
Seong-Cheol Lee ◽  
Kyung-Joon Shin ◽  
Byung-Hwan Oh
Keyword(s):  
Cyclic Loading ◽  
Fatigue Behavior ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Fiber Reinforced Concrete ◽  
Test Method ◽  
Single Fiber ◽  
Pull Out ◽  
The Individual ◽  
Cyclic Degradation

Recently, many studies have been conducted to examine the behavior of fiber-reinforced concrete (FRC) subjected to cyclic loading. However, cyclic and fatigue behavior is so complex that the mechanism of degradation cannot be cleared just by simple mechanical tests such as flexural and tensile tests of FRC specimens that measure typical overall behavior of the material. Besides these kinds of investigations, the individual behavior of the constituents and the interaction between them need to be investigated to reveal the cyclic degradation and fatigue mechanism of FRC detail. So far, only a few experiments have been devoted to the cyclic degradation of fibers in FRC. Therefore, cyclic pull-out behavior of single fiber is investigated in this study. A main objective of this article is to propose a test method for a cyclic pull-out test of a single fiber and to investigate the degradation behavior of single PVA fibers under cyclic loading conditions. Single PVA fibers were tested using quasi-static and cyclic loading methods, and the test results revealed the bridging load of PVA fibers decreases continuously and it become less than half the initial load during the cyclic loading process.

Fabrication of Cf/SiC Composites by Hot-Pressing

2007 ◽  
Vol 334-335 ◽  
pp. 1045-1048 ◽  
Author(s):  
Yu Sheng Ding ◽  
Shao Ming Dong ◽  
Qing Zhou ◽  
Dong Liang Jiang
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
Fracture Behavior ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Pull Out ◽  
Continuous Carbon Fiber ◽  
Sintering Conditions ◽  
Fiber Matrix ◽  
Sic Composites

Continuous carbon fiber-reinforced silicon carbide (Cf/SiC) composite was fabricated by hot-pressing, via liquid phase sintering. Sintering conditions strongly affect the densification process, and therefore dominate the mechanical properties and fracture behavior. The composites under the lower sintering temperature behaves less densified matrix and it demonstrates a relatively weak fiber/matrix bonding allowing the longer fibers pull-out. Increasing sintering temperature could accelerate the densified matrix and make fiber/matrix bonding stronger. In this case, the shorter fibers pull-out was predominant fracture behavior and it could improve mechanical properties.

scholarly journals Evaluation of Fiber/Matrix Interfacial Strength of Neutron Irradiated SiC/SiC Composites Using Hysteresis Loop Analysis of Tensile Test

2006 ◽  
Vol 47 (1) ◽  
pp. 207-210 ◽  
Author(s):  
Kazumi Ozawa ◽  
Tatsuya Hinoki ◽  
Takashi Nozawa ◽  
Yutai Katoh ◽  
Yuichi Maki ◽  
...  
Keyword(s):  
Tensile Test ◽  
Hysteresis Loop ◽  
Interfacial Strength ◽  
Loop Analysis ◽  
Fiber Matrix ◽  
Sic Composites

BN-Based Fiber Coatings by Wet-Chemical Coating

2019 ◽  
Vol 809 ◽  
pp. 421-426 ◽  
Author(s):  
Jonathan Maier ◽  
Andreas Nöth ◽  
Katrin Schönfeld
Keyword(s):  
Tensile Load ◽  
Fiber Surface ◽  
Tensile Tests ◽  
Dip Coating ◽  
Fiber Bundles ◽  
Coated Fiber ◽  
Fiber Coating ◽  
Pull Out ◽  
Sic Composites ◽  
Fiber Coatings

Fiber coatings for BN/SiC-and BN/Si3N4-bilayer systems were developed for the use in SiC/SiC composites. All coatings were produced with high process velocities of 500 m/h by a continuous roll-to-roll dip-coating process. The fiber surface was fully covered with a homogeneous coating and without fiber bridging. Tensile tests of fiber bundles were used to examine potential degradation of the fiber properties due to the application of the coatings. The coated fiber bundles showed a reduction of the maximum tensile load to 90.0 % for the BN/Si3N4 and to 86.7 % for the BN/SiC coating in comparison to the fiber bundle in the as-received state. A thermal treatment of the coated fiber bundles up to 1650 °C led to no reduction of their maximum tensile load. SiC/SiC composites were fabricated by polymer infiltration and pyrolysis. The flexural strength and strain of composites with BN/SiC fiber coating were improved to 467 MPa and 0.42 % in comparison to the composites without fiber coating. The composites with BN/SiC coating showed toughened fracture behavior with fiber pull-out effects.

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

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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