Elastic properties, voids effect

Hansong Huang, Ramesh Talreja, Effects of void geometiy on elastic properties of imidirectional fiber reinforced composites. Composites Science and Technology 65 (2005)pp. 1964-1981. 

Intrinsic craze formation is also reflected in the elastic properties of the material. The values of Young s modulus, E, listed in Table 2, clearly reveal both the effect of matrix orientation before craze initiation (X < and, the effect of voids after craze formation > A, )- The former causes E to increase, the latter results in a decrease of E. 

Huang H, Talreja R. Effect of void geometry on elastic properties of unidirectional fibre reinforced composites. Compos Sci Technol 2005 65 1964-81. 

Analyses have been carried out assuming a cavitated particle, that is, the particle is replaced by a void (see the section Cavitation of the Rubber Particles ). The analysis is applied to an annulus of epoxy resin. The volume fraction of the void is 20%. The elastic material properties used for the epoxy matrix are shown in Table I. The elastic-plastic material properties used are shown in Figure 4. Nonlinear geometric effects were included to take account of large deformations. Final failure of the cell was defined (23) to be the applied strain required for the maximum linear tensile strain in the resin to attain the value of 20%. 

The stress-strain behavior of deep-sea clay is not fimdamentally different than terrestrial counterparts but some important differences in parameters, such as elastic and shear modulus, may occur due to the high void ratios and fineness of materials. The effects of the removal of water pressure (over 60 MPa in ocean basins) on stress-strain and strength properties of deep-sea sediments is still a matter of discussion and there is very little reliable data for comparison of laboratory and in-situ properhes. The present approach is to generally ignore these possible effects but to make correchons to results along the lines developed for terrestrial soils. 

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