Fiber composites since 1985

Guide | The correct handling of CFRP Carbon

Properties of CFRP Carbon

CFRP - Carbon Fiber Reinforced Plastic
Car­bon Fiber Rein­forced Plas­tic (CFRP)

Car¬≠bon fiber mate¬≠ri¬≠als (CFRP) are mate¬≠ri¬≠als with out¬≠stand¬≠ing prop¬≠er¬≠ties: light, excep¬≠tion¬≠al¬≠ly stiff, of high strength, fatigue and cor¬≠ro¬≠sion resis¬≠tant. How¬≠ev¬≠er, due to the spe¬≠cial mate¬≠r¬≠i¬≠al prop¬≠er¬≠ties of the fiber, a few mea¬≠sures should be tak¬≠en to pre¬≠serve these advan¬≠tages for as long as pos¬≠si¬≠ble. Knowl¬≠edge of the com¬≠po¬≠si¬≠tion and struc¬≠ture of a car¬≠bon mate¬≠r¬≠i¬≠al allows pre¬≠dic¬≠tion of the max¬≠i¬≠mum load capac¬≠i¬≠ty val¬≠ues that can be achieved and the main¬≠te¬≠nance mea¬≠sures nec¬≠es¬≠sary to main¬≠tain them. Processed in a com¬≠pos¬≠ite part, the fiber is only one of the main load-bear¬≠ing com¬≠po¬≠nents; the con¬≠nec¬≠tion of the fibers and their rel¬≠a¬≠tive posi¬≠tion¬≠ing to each oth¬≠er are pro¬≠vid¬≠ed by the resin sys¬≠tem used.

Espe¬≠cial¬≠ly for struc¬≠tural¬≠ly load-bear¬≠ing (stressed) appli¬≠ca¬≠tions, the use of epoxy as a resin sys¬≠tem is still the best choice. As a result, excel¬≠lent fiber wet¬≠ting, high strength and load-bear¬≠ing capac¬≠i¬≠ty are achieved with the low¬≠est pos¬≠si¬≠ble mate¬≠r¬≠i¬≠al usage. To main¬≠tain the ben¬≠e¬≠fits of a car¬≠bon com¬≠pos¬≠ite over the long term, the fol¬≠low¬≠ing rec¬≠om¬≠men¬≠da¬≠tions can be made:

  • Avoid strong heat¬≠ing of the com¬≠po¬≠nent. The dark sur¬≠faces of car¬≠bon in par¬≠tic¬≠u¬≠lar absorb a lot of ener¬≠gy from sun¬≠light, for exam¬≠ple, and devel¬≠op a great deal of heat as a result. Con¬≠trolled post-cured com¬≠pos¬≠ite com¬≠po¬≠nents that are exposed to high tem¬≠per¬≠a¬≠tures in the process also lose some of their fatigue strength when exposed to heat.
  • Epoxy resins are not UV resis¬≠tant. Pro¬≠longed intense expo¬≠sure to UV rays attacks the mol¬≠e¬≠c¬≠u¬≠lar struc¬≠ture of the epoxy and alters its phys¬≠i¬≠cal properties.
  • Attacked epoxy has a ‚Äėchalky‚Äô char¬≠ac¬≠ter and has low fiber adhe¬≠sion. Should it sep¬≠a¬≠rate from the bond, the embed¬≠ded fiber is exposed to the weath¬≠er with¬≠out
    espe¬≠cial¬≠ly mois¬≠ture can then pen¬≠e¬≠trate the com¬≠pos¬≠ite and fur¬≠ther weak¬≠en the strength of the lam¬≠i¬≠nate. To avoid this pos¬≠si¬≠ble process, coat¬≠ing or paint¬≠ing the car¬≠bon com¬≠po¬≠nent is rec¬≠om¬≠mend¬≠ed. UV-resis¬≠tant polyurethane coat¬≠ings, which are also avail¬≠able as a clear mate¬≠r¬≠i¬≠al, are ide¬≠al for this pur¬≠pose.
    Car¬≠bon mate¬≠ri¬≠als, like met¬≠als, have good elec¬≠tri¬≠cal con¬≠duc¬≠tiv¬≠i¬≠ty. Accord¬≠ing¬≠ly, they (espe¬≠cial¬≠ly masts!) should be pro¬≠vid¬≠ed with suf¬≠fi¬≠cient ground¬≠ing if pos¬≠si¬≠ble or necessary.
  • Anoth¬≠er effect of the con¬≠duc¬≠tiv¬≠i¬≠ty is the increased cor¬≠ro¬≠sion of direct¬≠ly con¬≠nect¬≠ed met¬≠al objects on car¬≠bon, espe¬≠cial¬≠ly sus¬≠cep¬≠ti¬≠ble of course alu¬≠minum, which acts as an anode on car¬≠bon and thus cor¬≠rodes strong¬≠ly. For pro¬≠tec¬≠tion, insu¬≠la¬≠tion with a non-con¬≠duc¬≠tor is always rec¬≠om¬≠mend¬≠ed, i.e. the use of plas¬≠tic seals, or plas¬≠tic fit¬≠tings. Some hard chairs also weath¬≠er to a greater or less¬≠er extent in direct con¬≠tact with car¬≠bon, but the cor¬≠ro¬≠sion decreas¬≠es sig¬≠nif¬≠i¬≠cant¬≠ly as the grade of the steel increases.
  • A major advan¬≠tage of fiber com¬≠pos¬≠ites is the pos¬≠si¬≠ble ori¬≠en¬≠ta¬≠tion of the fiber direc¬≠tions accord¬≠ing to the expect¬≠ed force appli¬≠ca¬≠tions. Due to the high stiff¬≠ness of the car¬≠bon fiber along the fiber direc¬≠tion, opti¬≠mized com¬≠po¬≠nents can be designed and man¬≠u¬≠fac¬≠tured with a min¬≠i¬≠mum of mate¬≠r¬≠i¬≠al and the same stiff¬≠ness (com¬≠pared to oth¬≠er mate¬≠ri¬≠als). How¬≠ev¬≠er, the load-bear¬≠ing capac¬≠i¬≠ty of the com¬≠po¬≠nent axi¬≠al¬≠ly off¬≠set from this fiber direc¬≠tion (by about 90¬į) can¬≠not be achieved to the same extent. In order to be able to intro¬≠duce a minimum
  • In order to be able to intro¬≠duce a min¬≠i¬≠mum of mechan¬≠i¬≠cal shear forces, e.g. pipes, masts, etc. are man¬≠u¬≠fac¬≠tured with more wall thick¬≠ness than com¬≠pa¬≠ra¬≠ble com¬≠po¬≠nents, but they still do not reach the strength of e.g. aluminum.


So avoid the occur¬≠rence of abrupt or high loads due to trans¬≠verse forces, such as the spin¬≠naker pole hit¬≠ting the forestay under load, or apply rein¬≠force¬≠ments to par¬≠tic¬≠u¬≠lar¬≠ly vul¬≠ner¬≠a¬≠ble areas (sheath¬≠ing made of steel, alu¬≠minum or dou¬≠ble-lay¬≠er car¬≠bon tubes) at an ear¬≠ly stage.

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