Modulus of Composite Materials

As for tensile modulus of plastics (Table 8.14), the compressive modulus of composite deck boards (Table 8.15) follows the same trends as the elastic modulus with respect to a sample s degree of crystallinity [6]. 

TABLE 8.15 Compressive modulus values for actual composite deck boards, parallel or perpendicular to the length. Data are reported by the manufacturers or by the author. Data on wood are given in [3] or determined by the author  

R Shackelford and W. Alexander. CRC Material Science and Engineering Handbook, 3rd edition, CRC Press, Boca Raton, FL, 2001, p. 600-606. 

Svoboda and R.W. Lang. Property profiles and structure-property-relationships of polypropylene-wood-composites with high wood content. In Wood-Plastic Composites, A Sustainable Future. The Proceedings of International Conference, Applied Market Information, Bristol, UK, Vienna, Austria, May 14-16, 2002. 

Rowell, Specialty treatments. In Wood Handbook, Forest Products Society, Madison, WI, 1999, p. 19-7. 

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The elastic modulus of composite materials reinforced by discontinuous cylindrical fibers or lamellar shapes is expressed by the Halpin-Tsai equations [106, 230], as shown in the following equation ... 

Figure 26.11 shows the stress-strain behavior of ES30 filled with various levels of ATH. It can be seen that the yield stress increases with increasing level of ATH while the ultimate elongation is in excess of several hundred percent even for materials with more than 50wt% ATH. The modulus of composite materials can be modeled by the generalized Kemer equation ... 

Effect of Temperature on Flexural Modulus of Composite Materials... 

Compression molding, 2, 11, 87-89, 568 Compression-molded composite, 86 Compressive modulus of composite materials, 331... 

Sims G D, Nimmo W, Johnson A F and Ferriss D H (1994), Analysis of plate twist test for in-plane shear modulus of composite materials, NPL Working Draft, National Physical Laboratory, Teddington, UK. 

HASAWA. Health and Safety at Work, etc Act, 1975. See health and safety. Hashin s Equations. Expressions for the bulk and shear moduli, and hence Young s modulus, of composite materials, including porous materials. (A.G.Hashin and S. Shtrikman, J. Mech. Phy. Solids 11, 1963, pl27-140)... 

Many equations have been proposed for the transport properties of two-phase systems and in-depth details of the existing models are discussed elsewhere [4]. Noticing that virtually all the early theories neglected the effects of the particle shape, their packing density, and the possible formation of anisotropic clusters, Lewis and Nielsen modified the Halpin-Tsai equation for the elastic modulus of composite materials by incorporating the maximum volume fraction of filler cpm while still maintaining a continuous matrix phase [33,34]. Transposed to thermal conductivity Lewis and Nielsen s equation becomes... 

R. L. Hewitt and M. C. de Malherbe, An Approximation for the Longitudinal Shear Modulus of Continuous Fibre Composites, Journal of Composite Materials, April 1970, pp. 280-282. 

Figure 5.108 Schematic comparison of stress-strain diagrams for common reinforcing fibers (HMG = high modulus graphite) and whiskers. Reprinted, by permission, from A. Kelly, ed.. Concise Encyclopedia of Composite Materials, revised edition, p. 312. Copyright 1994 by Elsevier Science Publishers, Ltd.

The effective elastic properties (the bulk modulus K and the shear modulus p) of the connecting set and nonconnecting set may be calculated by using standard formulas from the physics of composite materials (e.g., Hashin-Strikman formulae [133, 134]) accounting for the tensor nature of elastic properties (Fig. 46). 

The preparation of composite materials in general is a very important appHca-tion of the mechanical properties of nanodiamond. With many polymers like caoutchouc, polysiloxanes, fluoroelastomers polymethacrylates, epoxy resins, etc., composites with markedly improved mechanical characteristics have already been obtained from the noncovalent incorporation of nanodiamond by simple admixing during polymerization. The modulus of elasticity, the tensile strength, and the maximal elongation of the material all increase upon this modification. Depending on the basic polymer, just 0.1-0.5% (w/w) of nanodiamond are required to achieve this effect (Table 5.3). Polymer films can also be reinforced by the addition of nanodiamond. For a teflon film with ca. 2% of nanodiamond added, for example, friction is reduced at least 20%, and scratches inflicted by mechanical means are only half as deep as in neat teflon. 

FLEXURAL STRENGTH (MOR) AND FLEXURAL MODULUS (MOE) OF COMPOSITE MATERIALS AND PROFILES... 

Temperature coefficient, 205, 206, 335, 495, 506, 509, 511, 512 Temperature factor, 303 Temperature, effect on viscosity, 633 Tensile modulus of elasticity of composite materials, 329... 

Dynamic mechanical characteristics, mostly in the form of the temperature response of shear or Young s modulus and mechanical loss, have been used with considerable success for the analysis of multiphase polymer systems. In many cases, however, the results were evaluated rather qualitatively. One purpose of this report is to demonstrate that it is possible to get quantitative information on phase volumes and phase structure by using existing theories of elastic moduli of composite materials. Furthermore, some special anomalies of the dynamic mechanical behavior of two-phase systems having a rubbery phase dispersed within a rigid matrix are discussed these anomalies arise from the energy distribution and from mechanical interactions between the phases. 

A mineral with an approximate formula Mg7Sig023 has a stmcture that is made up of alternating layers with compositions of 7MgO and 8Si02. Estimate the elastic modulus of the material when stressed (a) parallel and (b) perpendicular to the layers. The elastic modulus and density of MgO are 210.3 GPa and 3580 kg m, respectively,... 

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