2 MIX the paint to match the floor color, and paint the inside surface and edges of the damage area
. Clean off any paint that gets on the surrounding vinyl surface.
To investigate the correlation between the CAI and the damage area, an assumption was made that the residual compressive strength (CAI) of a composite was proportional to the fraction of the linear dimension of the specimen width that had not been damaged.
In this Equation, A is the damage area, and [A.sub.0] is a parameter for the characteristic area before impact, which could be determined by fitting the equation with the experimental data.
Figure 9 shows that the CAI's are plotted as a function of damage area for the toughened and conventional composites after impact by the two impactors, respectively.
The CAI's for the untoughened composite apparently fell onto a smooth curve, but they were much lower than those of the toughened composite at the same impact damage area. Since most of the laminate specimens of the conventional composite were much extensively damaged at the impact energy range used, attempts were not made to fit the above equation to the data.
The extent of damage as represented by the magnitude of damage areas was calculated from the TTU results.
At the same indentation, the untoughened composite exhibited significantly greater damage areas than the toughened composite.
Figure 6 shows the damage areas as a function of impact energy for the toughened composite.