scholarly journals Compression Strength of Carbon Fiber Laminates Containing Flaws with Fiber Waviness

2004 ◽  
Author(s):  
Darrell Avery ◽  
Daniel Samborsky ◽  
John Mandell ◽  
Doug Cairns
Keyword(s):  
Carbon Fiber ◽  
Compression Strength ◽  
Fiber Waviness

The wavenumber imaging of fiber waviness in hybrid glass–carbon fiber reinforced polymer composite plates

2021 ◽  
pp. 002199832110476
Author(s):  
Haiyan Zhang ◽  
Yan Ren ◽  
Jiaxin Song ◽  
Qi Zhu ◽  
Xuefen Ma
Keyword(s):  
Carbon Fiber ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Layered System ◽  
Fiber Reinforced ◽  
Fiber Waviness ◽  
Computational Performance ◽  
Reinforced Polymer ◽  
Glass Carbon ◽  
Carbon Fiber Reinforced

Out-of-plane waviness is one of the most common defects which degenerates the strength, stiffness, and fatigue life of hybrid glass–carbon fiber–reinforced polymer composites (FRPs). An accurate and high-speed non-destructive testing method is highly desired for large composite structures in industries. Ultrasonic phased array is a great candidate for such application. This paper applies the wavenumber algorithm to image the waviness in hybrid FRP plates which are a multi-layered medium. The central frequency of 5 MHZ is chosen in order to maximize the ply resonance. Transducers are migrated virtually to each interface between glass and carbon plies in order to overcome the difficulty of wave propagation analysis in such multi-layered system. The wavenumber algorithm demonstrates a better computational performance compared to that of the traditional total focusing method (TFM) in time domain up to 6 times. The glass ply depth and waviness angle can be more accurately presented with relative errors less than 1.5% and 14.8%, respectively. In addition, the resin-rich defect characterization is also achievable with a maximum error of 14.4%.

Detection of fiber waviness in carbon fiber prepreg using Eddy current method

2021 ◽  
pp. 100981
Author(s):  
Yanfei Liao ◽  
Jingjing Wang ◽  
Zhiwei Zeng ◽  
Junming Lin ◽  
Yonghong Dai
Keyword(s):  
Carbon Fiber ◽  
Eddy Current ◽  
Current Method ◽  
Eddy Current Method ◽  
Fiber Waviness

Research on compression properties of unidirectional carbon fiber reinforced epoxy resin composite (UCFREP)

2020 ◽  
pp. 002199832097217
Author(s):  
Zhao Changfang ◽  
Zhou Zhitan ◽  
Zhao Changxing ◽  
Zhu Hongwei ◽  
Zhang Kebin ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Strain Rate ◽  
Epoxy Resin ◽  
Compression Strength ◽  
Resin Composite ◽  
Dynamic Compression ◽  
Compression Failure ◽  
Compression Properties ◽  
Epoxy Resin Composite ◽  
Shear Cracking

To research the axial compression properties of unidirectional carbon fiber reinforced epoxy resin composite (UCFREP), the compression experiments at different strain rates were carried out by using the MTS universal electronic testing machine and the equipment of split Hopkinson pressure bar (SHPB). Furthermore, the finite element analysis (FEA) was also used to study the compression properties of UCFREP with different conditions. The true stress-strain curves in quasi-static and dynamic compression were obtained, and the relationship between yield limit and strain rate was coupled. The microstructure of the failure area was observed by scanning electron microscope (SEM). A formula for predicting compression strength of combined buckling under the quasi-static condition was presented. The application range of Chang-Chang failure criterion was discussed by FEA, and the compression failure of UCFREP with different fiber directions was predicted. The results show that UCFREP has the obvious strain rate effect, the mechanical properties at dynamic compression are nonlinear. Shear is the main compression failure mode, which includes the shear cracking of matrix between fibers and the shear buckling of fiber. The direction of the fiber is the main factor that causes the shear cracking, such as the shear cracking shows the feature of 45° when the direction of the fiber is 45°. As a conclusion, increasing the shear strength of matrix and fiber will be a way to increase the compression strength of UCFREP. This paper could be used as a reference to develop the new constitutive model, especially considering the nonlinear effect.

Electromechanical study of carbon fiber composites

1998 ◽  
Vol 13 (11) ◽  
pp. 3081-3092 ◽  
Author(s):  
Xiaojun Wang ◽  
Xuli Fu ◽  
D. D. L. Chung
Keyword(s):  
Carbon Fiber ◽  
Electrical Resistance ◽  
Fiber Composites ◽  
Single Fiber ◽  
Fiber Direction ◽  
Carbon Fiber Composites ◽  
Fiber Waviness ◽  
Pull Out ◽  
The Matrix ◽  
Fiber Matrix

Electromechanical testing involving simultaneous electrical and mechanical measurements under load was used to study the fiber-matrix interface, the fiber residual compressive stress, and the degree of marcelling (fiber waviness) in carbon fiber composites. The interface study involved single fiber pull-out testing while the fiber-matrix contact electrical resistivity was measured. The residual stress study involved measuring the electrical resistance of a single fiber embedded in the matrix while the fiber was subjected to tension through its exposed ends. The marcelling study involved measuring the electrical resistance of a composite in the through-thickness direction while tension within the elastic regime was applied in the fiber direction.

Forming Process and Mechanical Properties of Fiber Reinforced Polymer Concrete for Elementary Machine Parts

2013 ◽  
Vol 432 ◽  
pp. 98-103
Author(s):  
Wen Feng Bai ◽  
Peng Yin ◽  
Shou Cheng Yan
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Glass Fiber ◽  
Compression Strength ◽  
Fiber Reinforced Polymer ◽  
Polymer Concrete ◽  
Fiber Reinforced ◽  
Forming Process ◽  
Reinforced Polymer ◽  
Better Than

For the good vibration alleviating properties, polymer concrete (PC) has attracted much attention in the field of elementary machine components. In order to get more excellent mechanical properties, the forming process and mechanical properties of PC were concerned. In this research, glass fiber and carbon fiber were applied to improve the mechanical properties of PC. A series of PC and fiber reinforced polymer conctete (FRPC) specimens were prepared basing on the orthogonal tables for property test. Compression strength test was carried out. It is obvious that FRPC is better than PC as far as compression strength is concerned, and carbon fiber reinforced polymer concrete (CFRPC) is better than glass fiber reinforced polymer concrete (GFRPC). Trend curves about the relationship between fiber length and compression strength, as well as that between fiber dosage and compression strength were drawn. Relationship between the considered factors and compression strength is analyzed basing on the experiment results and the trend curves. Strengthening fibers would bear most of the internal stress when the specimen is faced to outer loads. Thus, FRPC has much better properties than PC. Mechanical properties of CFRPC are relatively better than that of GFRPC, for the strength of carbon fiber is better than that of glass fiber. It could be concluded that glass fiber is the proper strengthening fiber for PC considering both technical and economical factors.

Influences of in-plane and out-of-plane fiber waviness on mechanical properties of carbon fiber composite laminate

2018 ◽  
Vol 37 (13) ◽  
pp. 877-891 ◽  
Author(s):  
Chenjun Wu ◽  
Yizhuo Gu ◽  
Liang Luo ◽  
Peng Xu ◽  
Shaokai Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Failure Modes ◽  
Fiber Composite ◽  
Charpy Impact ◽  
Compressive Property ◽  
Mechanical Degradation ◽  
Carbon Fiber Composite ◽  
Fiber Waviness ◽  
Out Of Plane

Based on the curing process of carbon fiber/epoxy prepreg with autoclave, two kinds of unidirectional carbon fiber laminates with in-plane and out-of-plane waviness were fabricated by rolling prefabricated out-of-plane waviness and inserting prepreg strip, respectively. Fiber waviness defects in composites were characterized by waviness ratio. The specimens containing fiber waviness were successfully prepared with almost the same fiber content and low porosity. The influences of fiber waviness with different waviness ratio on tensile, compressive, and charpy impact properties of unidirectional laminates were studied, and the corresponding failure modes were observed. The mechanism of the effects of fiber waviness on mechanical properties was discussed. The experimental results show that tensile property and compressive property decrease by in-plane buckling and out-of-plane wrinkling, especially with large waviness ratio. Reduction of 33.0% of compressive strength with out-of-plane wrinkling is seen in the case of 0.037 waviness ratio, while 25.4% reduction is obtained for in-plane buckling under 0.038 waviness ratio. Charpy impact strength decreases by in-plane buckling, whereas increases by out-of-plane wrinkling. Failure morphologies of various specimens are changed by fiber waviness, which are consistent with the mechanical degradation. In addition, there are some differences on the sensitivity of mechanical properties to different types of fiber waviness. Tensile strength is more sensitive to in-plane buckling in comparison with out-of-plane wrinkling, and compressive property is more sensitive to out-of-plane wrinkling.

The Influence of GI and GII on the compression after impact strength of carbon fiber/epoxy laminates

2017 ◽  
Vol 52 (8) ◽  
pp. 991-1003 ◽  
Author(s):  
Alan Tate Nettles ◽  
Luke Scharber
Keyword(s):  
Carbon Fiber ◽  
Impact Strength ◽  
Compression Strength ◽  
Epoxy Resins ◽  
Impact Damage ◽  
Compression After Impact ◽  
The Difference ◽  
Type Of Failure ◽  
Carbon Fiber Epoxy ◽  
Residual Compression

This study measured the compression after impact strength of IM7 carbon fiber laminates made from epoxy resins with various mode I and mode II toughness values to observe the effects of these toughness values on the resistance to damage formation and subsequent residual compression strength-carrying capabilities. A total of seven different epoxy resin systems were used ranging in approximate GI values of 245–665 J/m2 and approximate GII values of 840–2275 J/m2. The results for resistance to impact damage formation showed that there was a direct correlation between GII and the planar size of damage as measured by thermography. Subsequent residual compression strength testing suggested that GI had no influence on the measured values and most of the difference in compression strength was directly related to the size of damage. Thus, delamination growth assumed as an opening type of failure mechanism does not appear to be responsible for the loss of compression strength.

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