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The fracture toughness of carbon fiber reinforced plastics is governed by the mechanisms: 1) debonding between the carbon fiber and polymer matrix, 2) fiber pull-out, and 3) delamination between the CFRP sheets.<ref name=":1">{{cite book |title=Composite Materials |last=Chawla |first=Krishan |publisher=Springer |year=2013 |isbn=978-0-387-74364-6 |location=United States of America }}</ref> Typical epoxy-based CFRPs exhibit virtually no plasticity, with less than 0.5% strain to failure. Although CFRPs with epoxy have high strength and elastic modulus, the brittle fracture mechanics present unique challenges to engineers in failure detection since failure occurs catastrophically.<ref name=":1"/> As such, recent efforts to toughen CFRPs include modifying the existing epoxy material and finding alternative polymer matrix. One such material with high promise is [[polyether ether ketone|PEEK]], which exhibits an order of magnitude greater toughness with similar elastic modulus and tensile strength.<ref name=":1"/> However, PEEK is much more difficult to process and more expensive.<ref name=":1"/>
Despite their high initial strength-to-weight ratios, a design limitation of CFRPs are their lack of a definable [[fatigue limit]]. This means, theoretically, that stress cycle failure cannot be ruled out. While steel and many other structural metals and alloys do have estimable fatigue or endurance limits, the complex failure modes of composites mean that the fatigue failure properties of CFRPs are difficult to predict and design against; however emerging research has shed light on the effects of low velocity impacts on composites.<ref>{{Cite journal |last=Liao |first=Binbin |last2=Wang |first2=Panding |last3=Zheng |first3=Jinyang |last4=Cao |first4=Xiaofei |last5=Li |first5=Ying |last6=Ma |first6=Quanjin |last7=Tao |first7=Ran |last8=Fang |first8=Daining |date=2020-09-01 |title=Effect of double impact positions on the low velocity impact behaviors and damage interference mechanism for composite laminates |url=https://www.sciencedirect.com/science/article/pii/S1359835X20302037 |journal=Composites Part A: Applied Science and Manufacturing |volume=136 |pages=105964 |doi=10.1016/j.compositesa.2020.105964 |issn=1359-835X}}</ref>
Environmental effects such as temperature and humidity can have profound effects on the polymer-based composites, including most CFRPs. While CFRPs demonstrate excellent corrosion resistance, the effect of moisture at wide ranges of temperatures can lead to degradation of the mechanical properties of CFRPs, particularly at the matrix-fiber interface.<ref>{{cite journal|title= Temperature effect during humid ageing on interfaces of glass and carbon fibers reinforced epoxy composites|journal= Journal of Colloid and Interface Science|date= 1 June 2006|pages= 111–117|volume= 298|issue= 1|doi= 10.1016/j.jcis.2005.12.023|pmid= 16386268|first= B. C.|last= Ray|bibcode= 2006JCIS..298..111R}}</ref> While the carbon fibers themselves are not affected by the moisture diffusing into the material, the moisture plasticizes the polymer matrix.<ref name=":1"/> This leads to significant changes in properties that are dominantly influenced by the matrix in CFRPs such as compressive, interlaminar shear, and impact properties.<ref>{{Cite journal|last1=Almudaihesh|first1=Faisel|last2=Holford|first2=Karen|last3=Pullin|first3=Rhys|last4=Eaton|first4=Mark|date=1 February 2020|title=The influence of water absorption on unidirectional and 2D woven CFRP composites and their mechanical performance|url=http://www.sciencedirect.com/science/article/pii/S1359836819346918|journal=Composites Part B: Engineering|language=en|volume=182|pages=107626|doi=10.1016/j.compositesb.2019.107626|s2cid=212969984|issn=1359-8368|access-date=1 October 2021|archive-date=1 October 2021|archive-url=https://web.archive.org/web/20211001034121/https://www.sciencedirect.com/science/article/abs/pii/S1359836819346918|url-status=live}}</ref> The epoxy matrix used for engine fan blades is designed to be impervious against jet fuel, lubrication, and rain water, and external paint on the composites parts is applied to minimize damage from ultraviolet light.<ref name=":1"/><ref>{{cite journal|title= Multi-factorial models of a carbon fibre/epoxy composite subjected to accelerated environmental ageing|journal= Composite Structures|date= May 2014|pages= 179–192|volume= 111|doi= 10.1016/j.compstruct.2013.12.028|first1= Enrique|last1= Guzman|first2= Joël|last2= Cugnoni|first3= Thomas|last3= Gmür}}</ref>
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In the United States, [[prestressed concrete]] cylinder pipes (PCCP) account for a vast majority of water transmission mains. Due to their large diameters, failures of PCCP are usually catastrophic and affect large populations. Approximately {{convert|19000|mi}} of PCCP were installed between 1940 and 2006. [[Corrosion]] in the form of hydrogen embrittlement has been blamed for the gradual deterioration of the prestressing wires in many PCCP lines. Over the past decade, CFRPs have been used to internally line PCCP, resulting in a fully structural strengthening system. Inside a PCCP line, the CFRP liner acts as a barrier that controls the level of strain experienced by the steel cylinder in the host pipe. The composite liner enables the steel cylinder to perform within its elastic range, to ensure the pipeline's long-term performance is maintained. CFRP liner designs are based on strain compatibility between the liner and host pipe.<ref>{{cite journal |last=Rahman |first=S. |date=November 2008 |title=Don't Stress Over Prestressed Concrete Cylinder Pipe Failures |journal=Opflow Magazine |pages=10–15 |url=http://www.awwa.org/publications/opflow/abstract/articleid/18373.aspx|volume=34|issue=11|doi=10.1002/j.1551-8701.2008.tb02004.x |s2cid=134189821 |url-status=live |archive-url=https://web.archive.org/web/20150402142138/http://www.awwa.org/publications/opflow/abstract/articleid/18373.aspx |archive-date=2 April 2015}}</ref>
CFRPs are more costly materials than commonly used their counterparts in the construction industry, [[
===Carbon-fiber microelectrodes===
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===Other applications===
[[File:Carbon Fiber Picks.jpg|alt=Dunlop "Max-Grip" carbon fiber guitar picks. Sizes 1mm and Jazz III.|thumb|[[Dunlop Manufacturing|Dunlop]] "Max-Grip" carbon fiber guitar picks. Sizes 1mm and Jazz III.]]
The fire resistance of polymers and thermo-set composites is significantly improved if a thin layer of carbon fibers is moulded near the surface because a dense, compact layer of carbon fibers efficiently reflects heat.<ref>{{cite journal |first1=Z. |last1=Zhao |first2=J. |last2=Gou |title=Improved fire retardancy of thermoset composites modified with carbon nanofibers|journal= Sci. Technol. Adv. Mater. |volume=10|issue=1 |year=2009|page= 015005 |doi=10.1088/1468-6996/10/1/015005 |bibcode=2009STAdM..10a5005Z|pmc=5109595 |pmid=27877268}}</ref>
[[File:Strandberg Boden Plini neck-thru & bolt on versions.jpg|thumb|Strandberg Boden Plini [[Neck-through-body construction|neck-thru]] & [[Bolt-on neck|bolt on]] versions that both utilize carbon fibre reinforcement strips to maintain rigidity.]]
CFRPs are being used in an increasing number of high-end products that require stiffness and low weight, these include:
* Musical instruments, including violin bows; guitar picks, necks (carbon fiber rods), and pick-guards; drum shells; bagpipe chanters; piano actions; and entire musical instruments such as carbon fiber cellos, violas, and violins, acoustic guitars and ukuleles; also audio components such as turntables and loudspeakers.
* Firearms use it to replace certain metal, wood, and fiberglass components but many of the internal parts are still limited to metal alloys as current reinforced plastics are unsuitable.
* High-performance drone bodies and other radio-controlled vehicle and aircraft components such as helicopter rotor blades.
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