Method of measuring the modulus of elasticity of carbon tow

In comparison to static and ultrasound methods, the examined method of measuring the modulus of elasticity of carbon fibres (tow) has the following advantages: the method of measurement is contactless and nondestructive; the minimum necessary linear size of the tow required for the measurement (5 cm) is much less than for other existing methods; the results of the measurement are not a function of the method of fastening and tension of the tow; continuous monitoring of the elastic properties during movement of the tow is possible; the E of the tow in both elastic and in the initial fibre material can be measured; this allows measuring the modulus of elasticity of fragments of structures manufactured with fibre materials. __________ Translated from Khimicheskie Volokna, No. 1, pp. 57–59, January–February, 2007.     

On the relationship between modulus of elasticity and microhardness

The correlation between the modulus of elasticity, on the one side, and Vickers microhardness and total microhardness, on the other side, was analyzed in the case of ultrahigh molecular weight polyethylenes. An extension of the application of the power relation between microhardness and the modulus (MH = aE^b) obtained by different methods was suggested. A linear dependence between constants obtained by Vickers and total microhardness measurements and other different techniques of modulus measurement was established, which signifies that both microhardness characteristics change their sensitivity toward the modulus in a similar way. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1794–1798, 2003     

Temperature dependence of the modulus of elasticity of industrial glasses

Translated from Steklo i Keramika, No. 2, pp. 12–13, February, 1992.     

Alternative estimation of the modulus of elasticity for dam concrete

The modulus of elasticity of dam concrete is hard to determine directly from tests due to the need for large specimens and testing machines. As an alternative, it is possible to predict experimental data of the elasticity module of fresh dam concrete through an evaluation of the results of standard specimens with the size of ?150×300 mm and assumptive acceptances of elasticity modules of aggregate in consideration of composite material models. A comparison was made between the 13 different composite material model results obtained in our study and the experimental data of Vilardell et al. [J. Vilardell, A. Aguado, L. Agullo, R. Gettu, Estimation of the modulus of elasticity for dam concrete, Cem. Concr. Res. 28 (1) (1998) 93-101]. As a result of this comparison, the models likely to yield the lowest number of errors were determined. Therefore, parallel (Voigt) and series (Reuss) models were found more appropriate for a reasonable prediction of elasticity modules of the dam concrete.     

Approximation of temperature dependence of the modulus of elasticity of glass

A refined nonlinear value of the main parameter of a material, i.e., the elongation modulus versus the instant temperature value, was suggested for introduction into the computational algorithm of tempering stresses.     

On the concentration dependence of the elasticity modulus of soybean globulin gels

Summary The concentration dependence of the elasticity modulus (G) of gels produced by heating soybean globulins (SBG) has been investigated in the concentration range C=7.5–58.4%. The tests included constant rate loading and stress relaxation. The experimental results are presented in the form of a modulus reduction parameter b(C)=G(C) / G(C), where C=15% corresponds to the standard reference state. Whatever the testing conditions, the results are described by a single smooth curve similar, to a constant factor, to the concentration dependence of the equilibrium elasticity modulus of SBG gels. The experimental relationship b (C) agrees with the theoretical concentration dependence of the equilibrium polymer gel modulus according to Hermanns if it is assumed that the gel-point of SBG, C_o=6.6 %. Within an order of magnitude this value of C_o is consistent with the experimental data. We have to thank the European Branch Director of Central Soya Intern., Inc., Mr.J.F.Casey for kindly providing us defatted soya flour.     

A multiscale model for modulus of elasticity of concrete at high temperatures

In this paper, the thermal degradation of modulus of elasticity of concrete is modeled by composite mechanics at three scales of observation: (a) at the level of concrete, (b) at the level of mortar, and (c) the cement paste level. At the latter, the change of volume fractions of the constituents are evaluated based on phase transformations which take place in different temperature ranges. Stoichiometric models are used to determine the volume changes of the constituents. At the mortar and concrete levels, the temperature dependence of fine and coarse aggregates is considered based on available test data. The multiscale chemo-mechanical model can be used to predict the temperature dependence and thermal degradation of the elastic concrete modulus. The model predictions are compared with test data in the literature as well as in-house test data.     

Developing a technology for production of bottom blocks with a low modulus of elasticity

The need for substantiated formulation of quality requirements for cathode blocks is emphasized. The ratio of the bending strength to elasticity modulus is proposed as a criterion for evaluating the strength properties of blocks. Techniques for improving this ratio in the production of carbon graphite materials are discussed.__________Translated from Novye Ogneupory, No. 11, pp. 16 – 17, November, 2004.     

Anisotropy of the modulus of elasticity in regenerated cellulose fibres related to molecular orientation

Regenerated cellulose fibres of different origin were tested in tension and by means of nanoindentation. Their degree of molecular orientation was characterised with birefringence measurements. An empirical relationship was set up between the degree of orientation expressed by birefringence and the modulus of elasticity parallel to the fibre direction, and the ratio between this modulus and the modulus transverse to the fibre direction, respectively.     

A determination of crosslink density from compression modulus data

A comparison of the crosslink densities calculated from compression modulus and stress–strain measurements is made for a series of natural rubber vulcanizates. Errors resulting from the use of accepted approximations and the effect of sample dimensions are also investigated.     

A new static method to determine the ratio of the shear modulus over the longitudinal osmotic modulus for swollen gels

Summary Swelling equilibrium of cylindrical gels under uniaxial compression has been studied. Based on the equivalence of the response of a network to osmotic deswelling and to deswelling induced by unidirectional compression a new method has been developed in order to determine the ratio of the shear modulus over the longitudinal osmotic modulus. For the experiments chemically cross-linked poly(vinyl acetate) gels swollen in toluene and iso-propyl alcohol have been used.