Physical Properties of the Composite

The physical properties of the composite play an important role in the measured mechanical properties. There is a direct dependence of mechanical properties on the physical properties. For example, the mechanical properties are directly dependent on fibre volume fractions. Here, we will consider the following physical property measurements.

1. Density

From our basic knowledge, the density of a material is defined as mass of the material per unit its volume. A test method to determine the density of a material is detailed in ASTM standard D792-91. This method is used determine the density of the composite and its constituents. The key points of the test procedure are explained in the following paragraphs.

The density of a material is determined using its weight in air  and in water . The densities of air (negligible) and water  are taken as known parameters in this test. The volume of the specimen is determined from the difference between the weight of the material in air and the weight in water and using the known density of water. Then the composite density   is given as

(8.3)