Igneous Fiber Reinforced Stealthy Armor for Submarine

Huawu Liu1,a, Fanjie Chu1,b, Zongbin Yang2，Hongming Dai3

1Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Tianjin 300160,

China

2Tianjin Silica Research Institute, Tianjin 300111, China

3Tianjin Dingshang Technology Limited, Tianjin 300384, China.

ahuawu_liu@yahoo.com.cn, bchufanjie2008@yahoo.com.cn.

Keywords: Igneous Glass, Continuous Filament, Stealthy Armor, Submarine.

Abstract: Igneous gem is a modified mineral glass without devitrification during processing, which

is far stronger than traditional basalt materials comprising both glass and crystal phases. Fiber made

by igneous gem is an ideal reinforcement for the armor of submarine, with advantages such as

infrared stealth (thermal insulation), sonar stealth (anti-vibration), radar stealth (transparent to radar

wave), heavy duty anticorrosion, bullet-proof (theoretical tensile strength 15,000MPa), fire resistant

(working temperature 910 oC) and ultralow temperature resistant (working temperature up to -269

oC), anti-aging and so on. The corresponding experimental data and mathematical models were

demonstrated in this study and compared with other high performance materials. The honeycomb

structure was proposed for the prefabricated composite and the advantages of such a material were

thoroughly stated.

Introduction

Igneous rocks are solidified magma, accounting for 95% of earth lithosphere. As the frame of the

earth, igneous rock is physically strong and chemically stable. The major skeleton compositions of

igneous rocks are silica, iron oxide and alumina. On the basis of silica content, igneous rocks are

classified into acidic felsic (silica> 65%), neutral intermediate (silica 52-65%), basic (silica

45-52%) and ultramafic (silica <45%), with more than 700 species [1, 2].

Basalt is one of the 700 igneous species. Transitional igneous products of secondary processing

comprise continuous basalt filament (6-20 microns in diameter and 10-200 km in length), basalt

rock wool (4 - 12 microns in diameter and 40-70 mm in length), and ultra-fine basalt wool (3

microns in diameter and 40-70 mm in length). The laboratory products of continuous basalt fiber

may be superior in terms of chemical stability and stronger than carbon, aramid and high molecular

weight polyethylene fibers [3-7]

However, the commercialization of basalt fiber has been unsuccessful. The devitrification is

difficult to control since the compositions vary significantly in basalt resources and the

microcrystallines born with the basalt fibers are defects, which lead to remarkable fluctuations of

product properties. So far, the annual production of continuous basalt fiber has been below 5000

tons, whereas fiberglass was 900 million tons in 2009 [6-7].

Igneous gem is made by modified volcanic glass using a patented anti-diversification method.

Therefore, there is no interior defects in the igneous fiber and the quality of commercialized is

stable with tensile strength >3000MPa.

Advanced Materials Research Vols. 332-334 (2011) pp 1955-1958Online available since 2011/Sep/02 at www.scientific.net© (2011) Trans Tech Publications, Switzerlanddoi:10.4028/www.scientific.net/AMR.332-334.1955

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Stealthy properties of igneous fiber

Materials with heat transfer coefficient less than 0.233 w/m.k under room condition were called

insulation material. The heat transfer coefficient of igneous fiber is 0.031-0.038 w/m.k (Table 1),

which is far smaller than 0.233 w/m.k. As a high performance insulation material, igneous fiber

certainly can block infrared radiation, thus the object protected by igneous composite is infrared

stealthy.

The sound absorption coefficient equals the ratio of absorbed sound energy to the total sound

energy. When the sound energy is completely reflected, the material sound absorption coefficient is

null. When the sound energy is completely absorbed, the material sound absorption coefficient is

one. Normally, the sound coefficient is between 0 and 1. The larger the absorption coefficient, the

better the sound absorption property is. From Table 1, we may find that the sound absorption

coefficient of igneous fiber is 0.9-0.99, which indicates that igneous fiber is an excellent sonar

stealth material.

Table 1.The physical properties of igneous, glass and carbon fibers

Igneous fiber E-glass fiber Carbon fiber

Density (g/cm3) 2.6-2.8 2.54 1.7-2.2

Working

temperature(oC)

-269-910 -60-350 350

Heat transfer

coefficient (w/m.k)

0.031-0.038 0.034-0.040 5-185

Thermal expansion

(10-6

/oC)

0.0023T+5.9207 5.4 0.1-0.3

Sound absorption

coefficient (%)

0.9-0.99 0.8-0.93 N/A

The radar stealthy property was measured in a key laboratory of stealthy materials and the sample

size was 20 cm x 20cm x 1cm. Electromagnetic test indicated that the dielectric constant and

dielectric loss decreased with the increase of frequency. In contrast, the magnetic permeability and

magnetic loss increased with the increase with frequency. It is radar invisible, since no reflection of

radar wave was detected by the facility. The regression models of dielectric constant, dielectric loss,

magnetic permeability and magnetic loss are given as follows:

Dielectric constant

ε′= -0.0247(GHz)2+0.1431(GHz)+7.6958 (R

2=0.9987, GHz∈8.2-12.4) (1)

Dielectric loss

ε″=-0.0133(GHz)2+0.2269(GHz)-0.5974 (R

2=0.9571, GHz∈8.2-12.4) (2)

Magnetic Permeability

µ′ =0.0089(GHz)2-0.1341(GHz)+1.3605 (R

2=0.9985, GHz∈8.2-12.4) (3)

Magnetic loss

µ″= 0.0026(GHz)2-0.0481(GHz)+0.2388 (R

2=0.9692, GHz∈8.2-12.4) (4)

1956 Advanced Textile Materials

Heavy-duty anticorrosion, bulletproof, fire resistance and icebreaking performance

Four percent of zirconia was added to modify the anticorrosion and waterproof properties of

igneous fiber. The weight losses of igneous and E-glass fibers were shown in Table 2, after 3 hour

boiling in 2N acid solution, 2N alkali solution and pure water. The anticorrosion properties of

igneous material are far better than these of glass fibers. According to standards NACE SP0108,

flakes, mainly glass flake, must be applied as pigment for the submarine coating, which implies that

glass is an excellent anticorrosion material and igneous gem is even better for protecting corrosion

from seawater.

Table 2. Weight loss ratios of igneous and glass fibers after 3 hours boiling.

Weight loss ratio of igneous

fiber

Weight loss ratio of E-glass

fiber

H20 0.18 0.7

HCL (2mol/L) 2.69 6.0

NaOH (2mol/L) 2.0 38.9

The theoretical tensile strength of glass is from 10,000MPa to 15,000MPa. The Chinese National

Glass Testing Centre validated that the igneous gem, a modified mineral glass, is one of the

strongest glasses. Hence, the theoretical tensile strength of igneous fiber is 15,000MPa, which is

100 times of the tensile strength of ordinary steel, though the density of igneous fiber is only 1/3 of

the steel density. Such a high strength to density ratio indicates that igneous fiber is an excellent

reinforcement for bulletproof armor.

The working temperature of igneous fiber ranges -269 oC to 910

oC, which means that igneous

fiber can withstand higher temperature generated by the rotation warhead than carbon fiber. In

addition, igneous fiber is thermal insulation, high strength and fully functional under extreme low

temperature. These properties are desirable for submarine cruising under ice water.

Table 3. Comparison of material characteristics [9]

Strength

(MPa)

Modulus

(GPa)

Density

(kg/ m3)

Operating temperature

(oC)

S275 steel 275~430 205 7900 1000

E-glass 2400 70-86 2490-2560 -200~650

Carbon 1000 100 1800 350

Igneous >3000MPa 98 2500-2800 -269~980

Advantages of prefabricated honeycomb composite for submarine armor

China is rich in population, but poor in resources per person. Therefore, the development of

ocean transportation would be the next engine of economic growth, after the driven by highway and

railway constructions [11]. A powerful navy is a must for all countries to guard their lifelines. The

igneous fiber reinforced composite may be a future replacement of steel, for manufacturing the hull

of submarine. This may lead to a ground breaking progress for theses countries limited by steel

resources. The prefabricated honeycomb structure is proposed for submarine armor, due to the

following reasons:

Advanced Materials Research Vols. 332-334 1957

• The body of submarine is reinforced by millions of fibers and cracks cannot rapidly develop

to tear up the body into pieces. In addition, honeycomb composite comprises plenty of

sealed hexagon tubes. The submarine still floats, even in catastrophe accidents.

• The vessel body will not be rusted, which significantly cuts down the maintaining time and

cost.

• The composite body is thermal insulation, which is more energy sustainable than steel

structure.

• The lowest working temperature of igneous is -269 oC and the material is very strong even

in ice water. The vessel armor is naturally an icebreaker.

• The properties of bulletproof, heavy-duty anticorrosion, radar stealth, infrared stealth and

sonar stealth make the warship superior in battle.

Conclusion

Igneous fiber is strong, high and low temperature resistance, anticorrosion, stealthy and

environmentally safe, which are great advantages in military applications, especially for the armor

of submarine. Its prefabricated honeycomb composite may be widely received in the future by

shipbuilding industry. Speeding up the industrialization process of igneous fiber may be particularly

significant to underpin the development of Chinese navy.

Reference

[1] http://en.wikipedia.org/

[2] http://www.geoscience.cn/

[3] X. Shen, H. Liu, C. Liu: Shandong Textile Science and Technology, (06) ：48-51.(2007)

[4] F. Qi, et al: High-tech fibers and application, 32(2):42-463.(2006)

[5]Y. Wu, et al: Journal of Materials Science & Technology, 18(4):357-360.(2002)

[6] P. Li, O. Zhi: Glass fiber, (3): 35-41.(2008)

[7] D. Ye: Glass fiber, (1): 39-41. (2008)

[8] Y. Jin, Shandong Textile Science and Technology, (2):37-40.(2010)

[9] http://www.ngcc.org.uk/

[10] D. Zhao and H. Liu: Technical Textiles,(8)39-44.(2010)

[11] http://www.cnita.org.cn/

1958 Advanced Textile Materials

Advanced Textile Materials 10.4028/www.scientific.net/AMR.332-334 Igneous Fiber Reinforced Stealthy Armor for Submarine 10.4028/www.scientific.net/AMR.332-334.1955