Structural Efficiency of a Natural Composite

1992 ◽  
Vol 278 ◽  
Author(s):  
Joseph E. Saliba ◽  
Georges E. Sawaya
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Pure Bending ◽  
Bending Properties ◽  
Principal Stresses ◽  
Fiber Volume ◽  
Structural Efficiency ◽  
The Individual ◽  
Natural Composite ◽  
Ply Orientation

AbstractThis study was initiated to investigate the structural efficiency of the “bessbeetle” (Odontotaenius Disjunctus) as compared to typical “man-made” or synthetic composites. This synthetic laminate is configured according to standard composites design practices. In fact, an orthotropic unidirectional T300 tape with circular fibers and 60% fiber volume fraction is used. The specific ply orientation of the symmetric man-made composite is [0/+45/-45/90]2S. The natural laminate studied is unsymmetric with the individual plies made of the same orthotropic unidirectional T300 tape but with different ply orientation. Contrary to previous beliefs the natural composite did not assume a balance of inplane and bending properties which in essence mimic the behavior of isotropic behavior. The results of the efficiency of the natural composite for tension did not show any noticeable advantages while the pure bending case resulted in higher values for the principal stresses in the unsymmetric laminate.

Bending Properties of Four-Layer Biaxial Weft Knitted Fabric Reinforced Composite Materials

2012 ◽  
Vol 182-183 ◽  
pp. 89-92
Author(s):  
Liang Sen Liu ◽  
Ye Xiong Qi ◽  
Jia Lu Li
Keyword(s):  
Composite Materials ◽  
Composite Laminates ◽  
Fiber Volume Fraction ◽  
Bending Strength ◽  
Volume Fraction ◽  
Bending Properties ◽  
Fiber Volume ◽  
Reinforced Composite ◽  
Weft Knitted Fabric ◽  
Bending Load

In this paper, a kind of composite laminates whose reinforcement is four-layer biaxial weft knitted (FBWK)fabric made of carbon fiber as inserted yarns has been made. The composite laminates have been impregnated with epoxy resin via resin transfer molding (RTM) technique. The samples of the experiments have been made from the composite laminates. The bending properties of the FBWK fabric reinforced composite materials with different fiber volume fraction have been investigated. The results show that the bending strength of this kind of composites increases with the fiber volume fraction increasing. The bending strength of FBWK reinforced composites with fiber volume fraction of 52% can reach 695.86 MPa. And the relationship between bending load and deflection is obviously linear.

Bending Properties of Five-Layer Biaxial Weft Knitted Fabric Reinforced Composite Materials

2011 ◽  
Vol 391-392 ◽  
pp. 359-363 ◽  
Author(s):  
Wei Geng ◽  
Ye Xiong Qi ◽  
Jia Lu Li
Keyword(s):  
Composite Materials ◽  
Fiber Volume Fraction ◽  
Bending Strength ◽  
Volume Fraction ◽  
Test Method ◽  
Bending Test ◽  
Bending Properties ◽  
Fiber Volume ◽  
Reinforced Composite ◽  
Bending Load

Five-layer biaxial weft knitted (FBWK) fabric is one kind of multilayered biaxial weft knitted (MBWK) fabric. FBWK fabric is made of carbon fiber as inserted yarns and stitched with polyester yarns, and it has been impregnated with epoxy via resin transfer molding (RTM) technique to manufacture the composite plates. The bending properties of the FBWK fabric reinforced composite are studied with the three-point bending test method. The bending properties of the FBWK fabric reinforced composite materials with different fiber volume fraction have been investigated. The results show that the relationship between bending load and deflection is obviously linear before reaching the maximum load. Within a certain range, the bending strength of this kind of composites increases with the fiber volume fraction increasing. When the fiber volume fraction is 57%, the bending strength is 1051.4 MPa.

Bending Properties of Three-Layer Biaxial Weft Knitted Fabric Reinforced Composite Materials

2011 ◽  
Vol 295-297 ◽  
pp. 1217-1220 ◽  
Author(s):  
Ye Xiong Qi ◽  
Jia Lu Li ◽  
Liang Sen Liu
Keyword(s):  
Composite Materials ◽  
Fiber Volume Fraction ◽  
Bending Strength ◽  
Volume Fraction ◽  
Knitted Fabric ◽  
Bending Properties ◽  
Fiber Volume ◽  
Reinforced Composite ◽  
Weft Knitted Fabric ◽  
Load Deflection Curve

In this paper, three-layer biaxial weft knitted fabric(TBWK) made of carbon fiber as inserted yarns and polyester yarns as knitted yarns , which is a kind of non-crimp fabric, has been impregnated with epoxy via RTM technique. The bending properties of the TBWK fabric reinforced composite materials with different fiber volume fraction have been investigated. The bending strength of TBWK reinforced composites with fiber volume fraction of 48.8% can reach 821.1 MPa. The results show that this kind of composites has good bending properties, and load - deflection curve shows obvious linear features.

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

scholarly journals Effect of Fiber Volume Fraction on Behavior of Concrete Beams Made with Recycled Concrete Aggregates

2019 ◽  
Vol 253 ◽  
pp. 02004
Author(s):  
Wael Alnahhal ◽  
Omar Aljidda
Keyword(s):  
Fiber Volume Fraction ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Recycled Concrete ◽  
Flexural Behavior ◽  
Beam Specimen ◽  
Rc Beam ◽  
Fiber Volume ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates

This study investigates the effect of using different volume fractions of basalt macro fibers (BMF) on the flexural behavior of concrete beams made with 100% recycled concrete aggregates (RCA) experimentally. A total of 4 reinforced concrete (RC) beam specimens were flexural tested until failure. The parameter investigated included the BMF volume fraction (0%, 0.5%, 1%, and 1.5%). The testing results of the specimens were compared to control beam specimen made with no added fibers. The experimental results showed that adding BMF improves the flexural capacity of the tested beams.

The Effects of Fiber Volume Fraction on the Experiment Modal Behavior of 45°/-45° Carbon Fiber Plain Woven Fabric/Epoxy Resin Composites

2012 ◽  
Vol 583 ◽  
pp. 150-153
Author(s):  
Qian Liu ◽  
Xiao Yuan Pei ◽  
Jia Lu Li
Keyword(s):  
Carbon Fiber ◽  
Epoxy Resin ◽  
Natural Frequency ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Laminated Composites ◽  
Woven Fabric ◽  
Resin Composites ◽  
Fiber Volume ◽  
Epoxy Resin Composites

The modal properties of carbon fiber woven fabric (with fiber orientation of 45°/-45°) / epoxy resin composites with different fiber volume fraction were studied by using single input and single output free vibration of cantilever beam hammering modal analysis method. The effect of different fiber volume fraction on the modal parameters of laminated composites was analyzed. The experimental results show that with the fiber volume fraction increasing, the natural frequency of laminated composites becomes larger and damping ratio becomes smaller. The fiber volume fraction smaller, the peak value of natural frequency becomes lower and the attenuating degree of acceleration amplitude becomes faster.

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