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As a next generation composite material, carbon fiber reinforced polymer (CFRP) has great potential to be widely used in manufacturing industries due to its outstanding mechanical properties. The high strength to weight ratio, and high stiffness inherent to CFRPs make them a desired material in various kinds of applications. CFRPs frequently experience bending loads while in use for such things as aircraft, automobiles, bridges, etc. Anisotropic behavior and limited in through thickness properties are major concerns which affect the performance of CFRPs. Moreover, in the interlaminar region, traditional CFRPs are often vulnerable to matrix sensitive damage such as compressive failure, delamination, and shear failure due to the absence of enough strength in through thickness direction. The tensile and compressive stress generated by the bending loads can weaken the interlaminar shear properties due to the absence of fibers in through thickness and ultimately can lead to catastrophic failure. This study introduces a novel approach with z-threaded CFRP (ZT-CFRP), which incorporates electrically aligned z-threaded carbon nanofibers (CNFs) as reinforcement. Flexural test using 3-point bending was performed on both control CFRP and ZT-CFRP samples reinforced with 1.0 wt.% carbon nanofiber z-threads. The results showed a 15% improvement in the flexural strength and about 36% linear elastic range increase for the ZT-CFRP laminates compared to the unmodified CFRP laminates, and validated the effectiveness of nanofiber Z-threading strategy in strengthening composite materials against flexural loading.
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Fiber Reinforced Compressed Earth Blocks: Evaluating Flexural Strength Characteristics Using Short Flexural Beams
There are ongoing research efforts directed at addressing strength limitations of compressed earth blocks (CEB) that inhibit their deployment for structural applications, particularly in areas where masonry systems are regularly subjected to lateral loads from high winds. In this paper, the authors focus specifically on the extent to which polypropylene (PP) fibers can be used to enhance the flexural performance of CEB. Cementitious matrices used for CEB production exhibit low tensile and flexural strength (brittle) properties. This work investigates plain (unreinforced) and fiber-reinforced specimens (short flexural beams) with fiber mass content of 0.2, 0.4, 0.6, 0.8, and 1.0% and ordinary Portland cement (OPC) content of 8%. The influence of the inclusion of fiber was based on tests conducted using the Standard Test Method for Flexural Performance of Fiber-Reinforced Concrete (ASTM C1609). Material properties that were quantified included first-peak strength, peak strength, equivalent flexural strength, residual strength, and flexural toughness. There was an observed improvement in the performance of the soil-fiber matrixes based on these results of these tests. It was also observed that when the fiber content exceeded 0.6% and above, specimens exhibited a deflection- hardening behavior; an indication of improvement in ductility. An equivalent flexural strength predictive model is proposed.
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- PAR ID:
- 10319743
- Date Published:
- Journal Name:
- Materials
- Volume:
- 14
- Issue:
- 22
- ISSN:
- 1996-1944
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/ma14226906
