X Young’s modulus

Table 13 World consumption at equal tensile stress (million m x Young s modulus)...

Table 1.3 compares the rigidity-modified data for consumption expressed as volume (million m )X Young s modulus (GPa). The elastic tensile modulus is arbitrarily fixed at 2 for plastics, 200 for steel and 75 for aluminium. 

Magnesium alloys have a Young s modulus of elasticity of approximately 45 GPa (6.5 x 10 psi). The modulus of rigidity or modulus of shear is 17 GPa (2.4 X 10 psi) and Poisson s ratio is 0.35. Poisson s ratio is the ratio of transverse contracting strain to the elongation strain when a rod is stretched by forces at its ends parallel to the rod s axis. 

Moduli and Poisson s Ratio. The Young s modulus of vitreous sihca at 25°C is 73 GPa (<1.06 x 10 psi), the shear modulus is 31 GPa (<4.5 X 10 psi), and the Poisson s ratio is 0.17. Minor differences in values can arise owing to density variations. The elastic modulus decreases with increasing density and Poisson s ratio increases (26). 

Sihcon carbide fibers exhibit high temperature stabiUty and, therefore, find use as reinforcements in certain metal matrix composites (24). SiUcon fibers have also been considered for use with high temperature polymeric matrices, such as phenoHc resins, capable of operating at temperatures up to 300°C. Sihcon carbide fibers can be made in a number of ways, for example, by vapor deposition on carbon fibers. The fibers manufactured in this way have large diameters (up to 150 P-m), and relatively high Young s modulus and tensile strength, typically as much as 430 GPa (6.2 x 10 psi) and 3.5 GPa (507,500 psi), respectively (24,34) (see Refractory fibers). 

Use the equation, with the average A, to calculate the approximate Young s modulus of (a) diamond and (b) ice. Compare these with the experimental values of 1.0 X 10 Nm" and 7.7 X 10 Nm" respectively. Watch the units ... 

Compo- sition number Resin type/parts per 100 parts of mbber (phr) Sulfur (phr) Y Method of preparation Cross- link density, r/2 (moles X 10 per ml of mbber) Rubber particle size (pm) Young s modulus (MPa) Stress at 100% strain (MPa) Tens. str. (MPa) UlL elong. (%) Tens. set (%)... 

The mechanics of materials approach to the estimation of stiffness of a composite material has been shown to be an upper bound on the actual stiffness. Paul [3-4] compared the upper and lower bound stiffness predictions with experimental data [3-24 and 3-25] for an alloy of tungsten carbide in cobalt. Tungsten carbide (WC) has a Young s modulus of 102 X 10 psi (703 GPa) and a Poisson s ratio of. 22. Cobalt (Co) has a Young s modulus of 30x 10 psi (207 GPa) and a Poisson s ratio of. 3. 

Tsai conducted experiments to measure the various moduli of glass-fiber-epoxy-resin composite materials [3-1]. The glass fibers and epoxy resin had a Young s modulus and Poisson s ratio of 10.6 x 10 psi (73 GPa) and. 22 and. 5 x 10 psi (3.5 GPa) and. 35, respectively. 

Material Type and condition Typical standard for implant application Ultimate tensile strength M Pa min 0.2% tensile yield stress M Pa Young s modulus X lO M Pa Elongation at fracture % min Compressive strength M Pa Vickers hardness Fatigue strength (10 cycles) M Pa... 

In the uniaxially oriented sheets of PET, it has been concluded that the Young s modulus in the draw direction does not correlate with the amorphous orientation fa or with xa "VP2(0)> 1r as might have been expected on the Prevorsek model37). There is, however, an excellent correlation between the modulus and x,rans,rans as shown in Fig. 15. It has therefore been concluded 29) that the modulus in drawn PET depends primarily on the molecular chains which are in the extended trans conformation, irrespective of whether these chains are in a crystalline or amorphous environment. It appears that in the glassy state such trans sequences could act to reinforce the structure much as fibres in a fibre composite. 

The values of Go and y are known and for the elastomer of Young s modulus of 2.1 MPa, [/o = 8 X 10 mm-s [12]. We can then evaluate 8 at ca. 20 mn. This value is perhaps a little high but of the same order of magnitude as earlier estimated [6]. Thus, despite some necessary approximations and simplifying hypotheses, we arrive at a semiquantitative explanation of the relationship between dewetting and therefore, presumably, wetting speed and the molecular structure of the elastomeric substrate. 

Byrex Chemical Resistance Glass has a Young s modulus of 6-1 x 10 dynes/cm , a modulus of rigidity of 2-5 x 10 dynes/cm and a Poisson s ratio of 0-22. Similar values are found for other glasses. 

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