Data for Young s modulus

Engineering Materials 1 Table 3.1 Data for Young s modulus, E... 

Estimate the thermal shock resistance AT for the ceramics listed in Table 15.7. Use the data for Young s modulus E, modulus of rupture c, and thermal expansion coefficient a given in Table 15.7. How well do your calculated estimates of AT agree with the values given for AT in Table 15.7 ... 

Table 11.1. Data for Young s modulus (E) and Poisson s ratio (v) at room temperature [16]. The bulk (B) and shear (G) moduli were calculated by substituting E and v into Equation 11.7, and rounded off to the nearest 10 MPa. The moduli (E, B and G) are all listed in MPa. See Table 11.6 and Table 11.7 for additional and/or alternative measured values of E.

For ceramics in general, where no data for Young s modulus E exists, equation (5.40) can be used to determine Kc values at the 20-30% confidence level. When values for E are known, better toughness data can be obtained by using the full Charles and Evans equation... 

Fig. 43 Fitting of composite models on introduction of IAF, for the sepiolite-filled NR nanocomposites symbols represent predicted values and the line indicates the best fit of the experimental data. YM Young s modulus...

In Figure 16.7 the experimental data for the unstabilized samples deviate from the predicted values for Young s modulus, (a) What do we mean by unstabilized. (b) How can you account for the difference in the predicted values and experimental values ... 

Reilly et al [24] tested femoral specimens specifically to determine whether the value for Young s modulus was different in tension and compression. A paired Student s t test showed no significant difference between the compressive and tensile moduli at the 95% confidence level. Calculations on their data show the the 95% confidence interval ranged... 

To describe the data at the bottom of Fig. 6.19, one defines a complex modulus (stress/strain ratio), G, as given in Eq. (1). Analogous expressions can be written for Young s modulus and the bulk modulus. The real component G represents the in-phase component of the modulus, and G , the out-of-phase component i stands for the square root of -1, as usual. 

The most frequently used materials data for short-term loading are those for Young s modulus and ultimate strain. Allowances for reductions include for duration of acting load, A2 for media influence incl. weathering, moisture, chemicals, and A3 for temperature. Various factors are selected that correspond with the material data, so that, in addition to reductions in terms of load, strength, stiffness (stability) and deformability (strain limit), distinctions are made for environmental influences and load duration, e. g., Aj for reduction due to load duration until fracture, A,y for stability, and A,u ultimate strength. 

The relationship between molecular weight and Young s modulus varies considerably between experimental data sets in the literature. The experimental data of Duek et al for Young s modulus versus molecular weight is shown in Figure 9.12. Initially, amorphous and crystalline poly(L-lactide) pins were degraded in phosphate buffer solution (pH 7.4) at 37°C for 6 months. Several of the values used... 

Figure 9.29 Experimental data of Duek et al. are shown for (a) number-average molecular weight and crystallinity, and (b) Young s modulus. Also shown in (b) is a representative fitting of the effective cavity theory model of GleadalP for Young s modulus degradation.

One of the observations from the tensile test was that although the sample standard deviation for stress (e.g., <5 and Og) is normally very small, the same deviation is greater for strain, and greater still for Young s modulus. Using the coefficient of variation (CV) to characterize the data scattering, where CV = (sample standard deviation) (sample mean), it was found that CV is 0.2 1.5% for stress, 2 5% for strain, and 2 10% for modulus. 

Special, uv-curable epoxy resins (qv) for substrate disks for optical data storage (Sumitomo BakeHte, Toshiba) excel by means of their very low birefringence (<5 nm/mm) and high Young s modulus. Resistance to heat softening and water absorption are similar to BPA-PC, but impact resistance is as low as that of PMMA. 

The factor 3 appears because the viscosity is defined for shear deformation - as is the shear modulus G. For tensile deformation we want the viscous equivalent of Young s modulus . The answer is 3ri, for much the same reason that = (8/3)G 3G - see Chapter 3.) Data giving C and Q for polymers are available from suppliers. Then... 

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. 

The designer must be aware that as the degree of anisotropy increases, the number of constants or moduli required to describe the material increases with isotropic construction one could use the usual independent constants to describe the mechanical response of materials, namely, Young s modulus and Poisson s ratio (Chapter 2). With no prior experience or available data for a particular product design, uncertainty of material properties along with questionable applicability of the simple analysis techniques generally used require end use testing of molded products before final approval of its performance is determined. 

For a Hookian material, the concept of minimum strain energy states that a material fails, for example cell wall disruption occurs, when the total strain energy per unit volume attains a critical value. Such an approach has been used in the past to describe a number of experimental observations on the breakage of filamentous micro-organisms [78,79]. Unfortunately, little direct experimental data are available on the Young s modulus of elasticity, E, or shear modulus of elasticity G representing the wall properties of biomaterial. Few (natural) materials behave in an ideal Hookian manner and in the absence of any other information, it is not unreasonable to assume that the mechanical properties of the external walls of biomaterials will be anisotropic and anelastic. 

After these calculations, a least squares fit is done on the first 250 milliseconds of data to obtain the initial slope, which is Young s Modulus. This represents 5% or less of the data for a run of at least 2.4 seconds at an initial data collection rate of 100 points per second. 

Deformation-hardening in the 5-50% deformation range is known to be proportional to either the Young s modulus, Y, or the shear modulus, G, in metals. The Young s modulus depends strongly on the shear modulus since Y = 2(1+v) G where v = Poisson s ratio. For both fee and bcc pure metals data... 

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