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TYPICAL PROPERTIES FOR APPENDIX A ADVANCED COMPOSITES Kenneth R. Berg A.I INTRODUCTION material and configuration is selected, a mini­ mum test program would then be initiated. For a company or institution that is designing composite material structures, or embarking Having a set of typical composite materials for the first time into the application of has advantages and disadvantages. For exam­ ple, if one were to design a structure utilizing advanced composite materials for structural only typical material properties, without the purposes, it is imperative that material prop­ knowledge of the scatter that may occur in erties be available. Of course it would be those properties, structural failure may occur. desirable to have a complete set of statistical Perhaps not immediately, nor on every struc­ Design Allowables, such as the statistical '.A: values for properties, or even the 'B' values, ture produced, but on an unknown statistical basis, at some point in time. However, prior to (see Chapter 33 for detailed definitions of a final design for a structure, the normal engi­ these values and Neal and Spiridgliozzi, 1987). neering procedure is to initiate the test Since complete statistical Design Allowables are not available, the next sought after mater­ program. The purpose of the test program is threefold: one, confirmation of the design; ial properties would be 'typical' properties. two, determine the scatter that occurs due to However 'typical' properties are not defined statistically and may be defined in many dif­ variations in materials and the manufacturing process; and three, over a period of time, ferent ways. Therefore it is important to discuss typical material properties and also either to confirm the material properties data­ discuss the means to achieve a set of typical base being used, or to accumulate test data for a material properties database. properties. The purpose of having a complete set of typical properties is to be able to design com­ A.2 TYPICAL PROPERTIES - CONSTITUENTS posite structures with a minimum of testing confirmation. Having a complete set of typical A.2.l FIBERS properties will allow design optimization, pre­ liminary design, cost and weight optimization One of the problems of determining typical and other trade-offs with a number of different properties is the variations that occur in the materials and candidate laminates with differ­ materials making up laminates. In the case of ent fiber orientations. Once an optimum glass fiber, the types of glass fiber and number of manufacturers is considerably less than with carbon fiber. Handbook of Composites. Edited by S.T. Peters. Published However, even with this limitation, there are in 1998 by Chapman & Hall, London. ISBN 0 412 54020 7 at least two major types of glass fiber, E-glass 1054 Typical properties for advanced composites and 5-2 glass. Within each of these glasses are Table A.l 'TYPical products from carbon fiber man­ variations in chemical composition, fiber diam­ ufacturers (available in USA) eter, fiber finish, fiber sizing, the number of individual fibers in a tow, roving, yarn, etc. AMOCO (Thornel)" Toho Rayon (Besfight) Manufacturers have different names for the P-100 HTAWlOO similar type of glass, for example the higher P-75 IM600 strength, higher modulus glasses. These fiber T-300 HM35 T650/35 glasses are the older S-glass (no longer avail­ Toray (Torayea) T650/42 able commercially), 5-2 glass and the R-glass Toho (Celion) T300 by a French manufacturer. Other countries fab­ T700s ricate the same type of glass, but with only G30-500 T800H minor differences in properties. G40-800 M40 For carbon fiber, not only are there the same G40-600 M46J variations as mentioned above for glass, but in Grafil (Grafil)b AKZO (Fortafil) addition, there are large variations in strength and modulus and in manufacturers, see Tables 34-700 F-5 42-650 F-3 Al andA2. 42-750 Based on the large number of variations in fibers, it would be virtually impossible to Hexeel (Magnamite) obtain complete statistical material properties AS4 for each variation. Even to obtain typical prop­ IM6 erties for each variation would not be IM7 practical. IM8 To reduce this problem to a practical level, it • Typical product name is necessary to analyze the usage of glass and b Grafil is a subsidiary of Mitsubishi Rayon Co. Ltd and carbon fibers (or other fibers). The usage of their fibers are called Grafil or Pyrofil. advanced composite fibers by 'pounds used per dollar expended', is estimated to be, in order of highest usage: E-glass, high strength Table A.2 Torayca fiber types (Toray, 1991) carbon (modulus of 227 GPa, (33 x 1()6 psi» Fiber type Number offilaments and then 5-2 glass. With this list, it is possible to develop typical properties for composites T300 lK, 3K, 6K, 12K fabricated from each of these fiber types. An T300J 3K,6K,l2K example of the determination of the strength T400H 3K,6K T700S 12K and modulus of the typical high strength car­ T800H 6K,12K bon fiber is shown in Fig. AI. The 'typical' TlOOOG 12K property becomes: Tensile modulus of 227 GPa T1000 12K (33 x 106 psi), and tensile strength of 4000 MPa M35J 6K,12K (580 ksi). M40J 6K,12K M46J 6K,12K M50J 6K A.2.2 RESIN SYSTEMS M55J 6K M60J 3K,6K The matrix for fiber composites can be classi­ M30 lK, 3K, 6K, 12K fied into two categories, metallic and M30SC 18K non-metallic. This discussion on typical prop­ M40 1K, 3K, 6K, 12K erties involves only non-metallic resin matrix M46 6K systems. M50 1K,3K Typical properties - constituents 1055 300,---------~----------------_. Typical PropertY -----'-~ 250 H'8treiigii,H4GpaH H'~*~~H Data from vUlaus lber manufacturers 50················ 5 • Epoxy/Amini + Epoxy/Anhydrld. lIE Vlnyl ••t.r I Po.,..... I!!I 'J'tpIc.1 Pro ...rty OL---~----~----~----~----~ 0 1I.ODO o 2 3 4 5 0 100 2ao 3DD 4DD 5DD 100 7ao 8DD lao Strength OPa Strength MPa Fig. A.l Typical strength and modulus for high Fig. A.2 Typical strength and modulus for E-glass strength carbon fiber. (Courtesy of Riggs composite - flexural strength. (Courtesy of Riggs Corporation.) Corporation.) As was discussed for fibers, only the high environmental considerations. Key among usage matrix systems in advanced composites these characteristics are: temperature, frac­ are considered as candidates for typical prop­ ture toughness, compression after impact, erties. In addition, for typical properties of crack propagation, humidity, stress concen­ advanced composites for structural applica­ trations, interlaminar shear, mechanical tions, only structural resin systems are fasteners in laminates, holes in laminates, candidates. Structural resins are defined as creep, damage tolerance and compatibility resins that have similar modulus and tensile with fiber finish. In determining typical prop­ strength as standard epoxy systems. For exam­ erties, these characteristics are not included ple, an applicable resin for structural but, as applicable, need to be considered for composites would have a modulus of approx­ the final design. imately 3.5 GPa (0.5 x 1()6 psi) and a tensile strength of approximately 100 MPa (15 ksi). The more popular structural resins are polyester, epoxy, vinyl ester and phenolic. For 800r----------------------------. typical composite properties, the use of any of !'rvPIO.' Value 840 MPa ~ 700 ." . these resins will allow a single typical prop­ :. '" erty (Fig. A.2) (CertainTeed Corporation, :I 800 ... .~ . 1989). Isoo A comparison for composites with different !400 ................. epoxy sizing from different manufacturers and j a typical value is shown in Fig. A3. 300 Figure A.4 shows a number of different 1 resin systems and the typical values for ~:::Ir-.-C-.I-I~-~-·~-~-~~-·PO~·-·_3----*-~--IIO~n-Q-30-~-_F-----.1 strength and modulus (Lubin, 1987). This data I H.rcul•• AS-4/1'ype G X Harcula. AS-4/Treated is for primarily fiber controlled properties. o~--------------------------~ There are properties in which the resin is the significant factor. These characteristics are Fig. A.3 Typical compression strength for carbon associated with stress concentrations and fiber fabric composites. (Courtesy of Riggs Corporation. ) lOS6 Typical properties for advanced composites 100 . Typical. VaLues . 90 Strength 608 MPa 80 .. ·Modulus 7c} GPa . ...... \ ..... ca 70 a. X"'~ .. !I CJ 60 en ::;, 50 '3 'tI 40 0 ::IE 30 20 +H.rOUI •• A.. 1eap *H.rcul•• A47D-8H • Hereul •• A-170-5H 10 XC.llon W-11U • Flbarlte HMF-1tSlM AFlb.rlt. HMF-.l41/34 0 0 100 200 300 400 500 600 700 Tensile Strength MPa Fig. A.4 Typical strength and modulus for carbon fiber fabric composites. (Courtesy of Riggs Corporation.) A.3 TYPICAL PROPERTIES - COMPOSITES ence the transverse strength and modulus of the base unidirectional laminate (100% 0° A.3.l FIBER CONTROLLED TYPICAL plies). The different strength resins shown on PROPERTIES Fig. A.S, are as follows: Fiber-reinforced composite materials are pri­ marily used to take advantage of the high Transverse Transverse strength and stiffness of the fiber. Therefore in modulus tensile strength (GPa) (MPa) most applications, the laminate orientation is designed so that the strength and modulus are Lower strength resin 8.6 41.4 controlled by the fiber properties. For example, Typical strength resin 10.0 55.2 for a typical fiber orientation in a laminate of Higher strength resin 11.4 69.0 0° /±fP /90°, the 0° plies control the failure of the laminate whenever the percentage of 0° plies is greater than 10%, (with a () greater than 700 r--~La~m~l~n.~I.~1~5"~OOr<.~15:="-=±.::..8°.L'7!.::O-"'-"-"'9O""-r--:-: .•.:7: tow=..::-;_= .... =RMI=. soo ... ,Fiber f.-ctu,. Cril cal (Ultimate) .... ~lJpIcaI.lrength ItHln ±l00). For () less than ±l0°, if the combined per­ .. ,:::.:;:::; *" Hlghwlnagth "-til centage of 0° and ±f)0 plies is greater than 10%, ..
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