Young's modulus of porous materials

The Young's modulus of porous alumina was determined by both sonic and bending tests. The pore structure of the specimens changes from interconnected at high porosities to disconnected at low porosities. The Young's modulus data can best be treated by the correlation proposed in Part 1 of this paper.     

Young's modulus and shear modulus of a composite shaft from resonance measurements

A simple method which uses axial and torsional vibration resonance for the measurement of Young's modulus, E, and shear modulus, G, of shafting is described. The moduli are used to calculate the resonance frequency of transverse vibration for comparison with a measured value. The agreement is extremely good so the measurements of E and G, and the theory used to calculate the transverse resonant frequency, must be precise.This method can be used in materials research but its simplicity also commends it for the quality control of composite material components in production.     

Young's modulus of porous brittle solids

A new equationE =E ₀ (1 –aP) ⁿ whereE andE ₀ are the Young's moduli at porosity,P, and zero, respectively, a andn are material constants, has been derived semi-empirically for describing the porosity dependence of Young's modulus of brittle solids. The equation satisfies quite well the exact theoretical solution for the values of Young's moduli at different porosities for model systems with ideal and non-ideal packing geometry. The equation shows excellent agreement with the data On- and-alumina over a wide range of porosity. Unlike the existing porosity-elastic modulus equations, the proposed equation satisfies the boundary conditions and is inherently capable of treating isometric closed pores as well as non-isometric interconnected pores. The parameters a and n provide information about the packing geometry and pore structure of the material.     

Young's modulus of lignin from a continuous indentation test

The deformation of lignin in a continuous ball indentation test was almost entirely elastic up to a stress of 2.2 × 10⁸ Pa (22 kg mm^–2). The load versus depth of indentation curve of the lignin followed closely the classical Hertz equation thus enabling the Young's modulus of lignin to be calculated. From these results a stress-strain curve for lignin was drawn.Visitor from Mechanical Engineering Department, University of Maryland, College Park, Md 20742, USA.     

Photo-induced characteristics of a Ti-Nb-Sn biometallic alloy with low Young's modulus

Anodic oxidation was conducted to Ti-Nb-Sn biometallic alloy for the purpose of giving photo-induced properties without losing the low Young's modulus of the alloy. The anodic oxide consists of primary TiO₂ with small amounts of Nb₂O₅ and SnO. Rutile-structured TiO₂ prepared in an electrolyte solution containing 1.2 M sulfuric acid exhibits photocatalytic activity and superhydrophilicity under ultraviolet (UV) light illumination, and superhydrophilicity in the absence of UV light illumination. The Young's modulus of Ti-Nb-Sn alloy with anodic oxide demonstrates a low value of approximately 50 GPa, which expands its application of the alloy as biomedical materials by adding photocatalytic sterilization function.     

The relations between the shear modulus, the bulk modulus and Young's modulus for porous isotropic ceramic materials

A relation between the shear modulus and Young's modulus of isotropic porous ceramics has been derived based on the Mori–Tanaka mean-field approach. The applicability of the relation has been evaluated using the experimental values available in the literature for the shear modulus, the bulk modulus and Young's modulus of porous ceramics prepared using various processing techniques and powder sizes. It is also shown that the ratio of the shear to Young's modulus of porous ceramics can be approximated by a constant value of 0.391.     

Determination of Young's modulus of dental composites: A phenomenological model

The Young's moduli of isotropic dental restorative composites are determined with a non-destructive dynamic method, which is based on the measurement of the duration of the fundamental period for the first harmonic of a freely oscillating sample. Statistical analysis of these results yields a phenomenological model in which Young's modulus is given by an exponential rule of mixtures of the matrix phase and the filler phase of the composites. It is found that this phenomenological rule is substantiated empirically.     

Effect of structure on the Young's modulus of Al-Cu-Ni alloys

Experimental measurements of the dynamic Young's modulus of a wide range of wrought Al-Cu-Ni alloy compositions have shown this property to depend not only on the volume fraction of the phases present in the alloy but also on the microstructure. The results can be described by the simple relationship: $$E = 76.6 + 94.6 V{_d} - 1.3d + 0.06\lambda$$ whereE is Young's modulus of the alloy (in GN m^?2),V _d is the volume fraction of all the dispersed phases, andd and λ are the respective average particle size and mean free path of all dispersed phases (inμm). In view of the wide range of alloys tested in the present work, the above equation is expected to apply reasonably well to most wrought aluminium alloys.     

Frequency dependency of Young's modulus of dental cocomposites

The Young's modulus of 15 commercial dental particulate filled composites was measured with three different methods. The materials were tested with static, low-frequency, and high-frequency elastic deformations. The analysis of the results shows that the frequency dependence of the Young's modulus of elasticity follows the same empirical law for all frequencies. Furthermore, knowledge of the Young's modulus for the resin component at all frequencies suffices to predict the Young's modulus of any particulate-filled composite.