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《纺织复合材料》课程参考文献（Composite Materials Handbook，Volume 3）Chapter 2 MATERIALS AND PROCESSES - THE EFFECTS OF VARIABILITY ON COMPOSITE PROPERTIES

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MIL-HDBK-17-3F Volume 3,Chapter 2 Materials and Processes-The Effects of Variability on Composite Properties 2.4.1.3.3 Advantages and disadvantages For many years glass composites have had a distinct strength to weight advantage.Although the rapid evolution of carbon and aramid fibers have gained advantages,glass composite products have still prevailed in certain applications.Cost per weight or volume,certain armament applications,chemical or galvanic corrosion resistance,electrical properties,and availability of many product forms remain as ex- amples of advantage.Coefficient of thermal expansion and modulus properties compared to carbon composites may be considered as typical disadvantages.When compared to aramid composites,glass has a disadvantage as to tensile properties but an advantage as to ultimate compression,shear proper- ties,and moisture pick-up. Commercial uses for glass products are many-fold.These include filtration devices,thermal and electrical insulation,pressure and fluid vessels,and structural products for automotive and recreation ve- hicles.Many uses are applicable to military and aerospace products as well.A partial listing would in- clude:asbestos replacement,circuitry,optical devices,radomes,helicopter rotor blades,and ballistic applications.Because of the many product forms,structural applications are limitless to fabricate.If there are limitations,compared to other fibers,they may include low thermal and electrical conductivity or perhaps melting temperatures when compared to carbon fibers. Typical properties for glass fibers and composite materials reinforced with continuous glass fibers are shown in Tables 2.4.1.3.3(a)-(d). TABLE 2.4.1.3.3(a)Typical glass fiber electrical properties. E S-2 HR Density lb/in3 0.094 0.089 0.090 g/cm3 2.59 2.46 2.49 Tensile Strength ksi 500 665 665 MPa 34,450 45,818 45,818 Modulus of Elasticity Msi 10.5 12.6 12.6 GPa 72.35 86.81 86.81 Ult.Elongation 4.8 5.4 5.4 Dielectric Constant 73°F(23C)@1MHZ 6.3-6.7 4.9-5.3 NA 2-12

MIL-HDBK-17-3F Volume 3, Chapter 2 Materials and Processes - The Effects of Variability on Composite Properties 2-12 2.4.1.3.3 Advantages and disadvantages For many years glass composites have had a distinct strength to weight advantage. Although the rapid evolution of carbon and aramid fibers have gained advantages, glass composite products have still prevailed in certain applications. Cost per weight or volume, certain armament applications, chemical or galvanic corrosion resistance, electrical properties, and availability of many product forms remain as examples of advantage. Coefficient of thermal expansion and modulus properties compared to carbon composites may be considered as typical disadvantages. When compared to aramid composites, glass has a disadvantage as to tensile properties but an advantage as to ultimate compression, shear properties, and moisture pick-up. Commercial uses for glass products are many-fold. These include filtration devices, thermal and electrical insulation, pressure and fluid vessels, and structural products for automotive and recreation vehicles. Many uses are applicable to military and aerospace products as well. A partial listing would include: asbestos replacement, circuitry, optical devices, radomes, helicopter rotor blades, and ballistic applications. Because of the many product forms, structural applications are limitless to fabricate. If there are limitations, compared to other fibers, they may include low thermal and electrical conductivity or perhaps melting temperatures when compared to carbon fibers. Typical properties for glass fibers and composite materials reinforced with continuous glass fibers are shown in Tables 2.4.1.3.3(a)-(d). TABLE 2.4.1.3.3(a) Typical glass fiber electrical properties. E S-2 HR Density lb/in3 0.094 0.089 0.090 g/cm3 2.59 2.46 2.49 Tensile Strength ksi 500 665 665 MPa 34,450 45,818 45,818 Modulus of Elasticity Msi 10.5 12.6 12.6 GPa 72.35 86.81 86.81 % Ult. Elongation 4.8 5.4 5.4 Dielectric Constant 73°F (23°C) @ 1 MHZ 6.3-6.7 4.9-5.3 NA

MIL-HDBK-17-3F Volume 3,Chapter 2 Materials and Processes-The Effects of Variability on Composite Properties TABLE 2.4.1.3.3(d)Typical cured epoxy/glass mechanical properties. Dual Purpose E Glass,Woven 7781 Style Standard Structural Structural/Adhesive Tensile Strength,ksi(MPa) 63(430) 48(330) Tensile Modulus,Msi(GPa) 3.8(36) 2.8(19) Compressive Strength,ksi(MPa) 60.(410) 50.(340) Compressive Modulus,Msi(GPa) 3.6(25) 3.2(22) Flexural Strength ksi,(MPa) 80.(550) 65(450) Flexural Modulus Msi,(GPa) 3.7(26) 3.3(23) Interlaminar Shear ksi,(MPa) 2.6(18) 3.8(26) Sandwich Peel,Ib/in width (N/m width) N.A. 30.(3.4) Metal-to-Metal Peel,Ib/lin.in.(N/lin.m) NA. 55(6.3) Specific Gravity gm/cm3(lb/in) 1.8(0.065) 1.6(0.058) Cured Resin Content%Wt. 33 48 Reference: Fabric MIL-C-9084,VIll B Resin ML-R-9300,Ty1 MIL-A-25463,Tyl1,C12 2.4.1.3.4 Common manufacture methods and variable Most often raw products (and/additives)are mixed and are premelted into marbles.This form facili- tates sampling for analysis but,more important,presents a raw product form for automated feeding to the individual melt furnaces.Another method is to feed,via hoppers,dried raw products directly to batch cans.Regardless of the raw form,the material is fed into furnaces to become molten at approximately 2800F(1500C).The molten mass flows onto plates which contain many bushings with small orifices from which the individual filaments are drawn.In some cases the individual bushings are heat controlled within <1F(0.6C).The diameter of the filaments is controlled by the viscosity of the glass melt and the rate of extrusion.Cooling or solidification occurs rapidly as the glass leaves the bushings in filament form under ambient conditions.Cooling is often added by water spray and/or application of the binders.The individual untwisted filaments are gathered and high speed wound on tubes or "cakes".Sometimes fin- ishes are applied after the strands are wound on the tubes then conditioned(dried).For products com- mon to this document the strands are "C"(continuous)filaments--not "S"(staple)filament.To produce rovings the strands are then creeled,unwound and gathered again to form ends or multiple untwisted strands.(See Table 2.4.1.3.4(a).)This process of gathering or combining is again repeated to form rov- ings of desired yields(yards per pound).For weaving of fabrics and braiding,the strands are twisted to form yarns.(See Table 2.4.1.3.4(b).)Single yarns are composed of single strands twisted by itself.Two (etc.)strand construction is two strands twisted to produce a single yarn.Plied yarns are made from twisting two or more yarns together.Twisting and plying is often referred to as "throwing".A variable in processing "C"filament products is the repeated tensioning required during the numerous product forms fabrication.Tensioning devices are used--such as:disc-type or "whirls",gate-type,tension bars or "S" bars,and compensating rolls in the delivery from the creels.Humidity is another controlled variable in the 2-14

MIL-HDBK-17-3F Volume 3, Chapter 2 Materials and Processes - The Effects of Variability on Composite Properties 2-14 TABLE 2.4.1.3.3(d) Typical cured epoxy/glass mechanical properties. E Glass, Woven 7781 Style Standard Structural Dual Purpose Structural/Adhesive Tensile Strength, ksi (MPa) 63 (430) 48 (330) Tensile Modulus, Msi (GPa) 3.8 (36) 2.8 (19) Compressive Strength, ksi (MPa) 60. (410) 50. (340) Compressive Modulus, Msi (GPa) 3.6 (25) 3.2 (22) Flexural Strength ksi, (MPa) 80. (550) 65 (450) Flexural Modulus Msi, (GPa) 3.7 (26) 3.3 (23) Interlaminar Shear ksi, (MPa) 2.6 (18) 3.8 (26) Sandwich Peel, lb/in width (N/m width) N.A. 30. (3.4) Metal-to-Metal Peel, lb/lin. in. (N/lin. m) N.A. 55 (6.3) Specific Gravity gm/cm3 (lb/in3 ) 1.8 (0.065) 1.6 (0.058) Cured Resin Content % Wt. 33 48 Reference: Fabric MIL-C-9084, VIII B Resin MIL-R-9300, Ty I MIL-A-25463, Ty I, C1 2 2.4.1.3.4 Common manufacture methods and variable Most often raw products (and/additives) are mixed and are premelted into marbles. This form facilitates sampling for analysis but, more important, presents a raw product form for automated feeding to the individual melt furnaces. Another method is to feed, via hoppers, dried raw products directly to batch cans. Regardless of the raw form, the material is fed into furnaces to become molten at approximately 2800°F (1500°C). The molten mass flows onto plates which contain many bushings with small orifices from which the individual filaments are drawn. In some cases the individual bushings are heat controlled within <1F° (0.6C°). The diameter of the filaments is controlled by the viscosity of the glass melt and the rate of extrusion. Cooling or solidification occurs rapidly as the glass leaves the bushings in filament form under ambient conditions. Cooling is often added by water spray and/or application of the binders. The individual untwisted filaments are gathered and high speed wound on tubes or "cakes". Sometimes finishes are applied after the strands are wound on the tubes then conditioned (dried). For products common to this document the strands are "C" (continuous) filaments--not "S" (staple) filament. To produce rovings the strands are then creeled, unwound and gathered again to form ends or multiple untwisted strands. (See Table 2.4.1.3.4(a).) This process of gathering or combining is again repeated to form rovings of desired yields (yards per pound). For weaving of fabrics and braiding, the strands are twisted to form yarns. (See Table 2.4.1.3.4(b).) Single yarns are composed of single strands twisted by itself. Two (etc.) strand construction is two strands twisted to produce a single yarn. Plied yarns are made from twisting two or more yarns together. Twisting and plying is often referred to as "throwing". A variable in processing "C" filament products is the repeated tensioning required during the numerous product forms fabrication. Tensioning devices are used--such as: disc-type or "whirls", gate-type, tension bars or "S" bars, and compensating rolls in the delivery from the creels. Humidity is another controlled variable in the

MIL-HDBK-17-3F Volume 3,Chapter 2 Materials and Processes-The Effects of Variability on Composite Properties twisting,plying,braiding,warping,slashing,gulling and weaving areas.These operations are facilitated to maintain a relative humidity of 60 to 70 percent range.During the glass processing operations surface abrasion is a factor which must be monitored.The many devices such as:guide eyes,spacer bars,roll- ers and such are subject to wear and must be maintained.Wear could also affect tensioning.These con- tact devices are manufactured from materials including:stainless steel,chromium plating,and ceramics. Additional information can be found in References 2.4.1.3.4(a)-(c). TABLE 2.4.1.3.4(a)Basic strand fiber designations and strand counts (Reference 2.4.1.3.1(c)). Filament Diameter Designation Strand Count(Number) TEX U.S.Customary SI U.S.Customary (um) (Letter) g/km 100Yd. Cuts/Lb. Yds./Lb. 5 D 11 450 45,000 > E 22 225 22,500 9 G 733 150 15.000 10 H 45 110 11,000 13 K 66 75 7,500 2.4.1.4 Boron Elemental boron fiber is formed as a deposition reaction on a hot tungsten wire which is continuously drawn through a reactor containing BCla and H3.The tungsten wire substrate also reacts to form tungsten boride in the core.The crystalline structure of the deposited boron is considered amorphous due to its small size (20A).Boron is available as a cylindrical fiber in two nominal diameters,4-and 5.6-mil(0.10 and 0.14 mm),which have a density of 2.57 and 2.49 g/cm(0.0929 and 0.0900 Ib/in),respectively. Chemical etching of the fiber surface produces a higher strength,but the process is not used commer- cially. Boron fiber is unmatched for its combination of strength,stiffness,and density.The tensile modulus and strength of boron fiber are 60 x 10 psi and 0.52 x 10 psi(40 GPa and 3600 MPa).Thermal conduc- tivity and thermal expansion are both low,with a coefficient of thermal expansion of 2.5-3.0 x 10/F (4.5-5.4 x 10/C).Typical end-use properties are shown in Table 2.4.1.4.Currently,the cost of boron fiber is approximately an order of magnitude higher than standard carbon fiber. 2-15

MIL-HDBK-17-3F Volume 3, Chapter 2 Materials and Processes - The Effects of Variability on Composite Properties 2-15 twisting, plying, braiding, warping, slashing, gulling and weaving areas. These operations are facilitated to maintain a relative humidity of 60 to 70 percent range. During the glass processing operations surface abrasion is a factor which must be monitored. The many devices such as: guide eyes, spacer bars, rollers and such are subject to wear and must be maintained. Wear could also affect tensioning. These contact devices are manufactured from materials including: stainless steel, chromium plating, and ceramics. Additional information can be found in References 2.4.1.3.4(a) - (c). TABLE 2.4.1.3.4(a) Basic strand fiber designations and strand counts (Reference 2.4.1.3.1(c)). Filament Diameter Designation Strand Count (Number) SI U.S. Customary TEX U.S. Customary (µm) (Letter) g/km 100 Yd. Cuts/Lb. Yds./Lb. 5 D 11 450 45,000 7 E 22 225 22,500 9 G 733 150 15,000 10 H 45 110 11,000 13 K 66 75 7,500 2.4.1.4 Boron Elemental boron fiber is formed as a deposition reaction on a hot tungsten wire which is continuously drawn through a reactor containing BCl3 and H3. The tungsten wire substrate also reacts to form tungsten boride in the core. The crystalline structure of the deposited boron is considered amorphous due to its small size (20Å). Boron is available as a cylindrical fiber in two nominal diameters, 4- and 5.6-mil (0.10 and 0.14 mm), which have a density of 2.57 and 2.49 g/cm3 (0.0929 and 0.0900 lb/in3 ), respectively. Chemical etching of the fiber surface produces a higher strength, but the process is not used commercially. Boron fiber is unmatched for its combination of strength, stiffness, and density. The tensile modulus and strength of boron fiber are 60 x 106 psi and 0.52 x 10 6 psi (40 GPa and 3600 MPa). Thermal conductivity and thermal expansion are both low, with a coefficient of thermal expansion of 2.5-3.0 x 10-6/F° (4.5-5.4 x 10-6/C°). Typical end-use properties are shown in Table 2.4.1.4. Currently, the cost of boron fiber is approximately an order of magnitude higher than standard carbon fiber

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