As Ti-O atoms are tightly bonded to the MWCNT surface, stresses associated with the Ti[O.sub.2] reconstruction should be transferred to the nanotubes, increasing the MWCNT network distortion and consequently the intensity of the D scatter band
These models assume that the scatter band of the fracture toughness values can be modeled using Weibull statistics.
It has been shown theoretically (21) that so long as no stable crack extension occurs during the loading, and the constraint in the specimen does not change, which means that the triaxiality of the stress and strain field at the crack tip does not change during the loading event, the scatter band follows the Weibull distribution.
An acceptable torque tension curve is generally shallow with a narrow scatter band
, whereas an unacceptable torque tension curve is steep with a large scatter.
Other, more practical books show the scatter band that exists in reality because of chemical, processing and procedural variations and measurement errors.
Figure 8 shows a typical scatter band between the tensile properties of test bars cut from standard ASTM keel blocks and the hardness of the same broken test bar shoulder.
The virgin, bottle flake, and recycled powder define a relatively narrow scatter band, with no significant differences between the materials.
In general, the fatigue results show a similar picture to the tensile results, with predominantly ductile failure (and hence a steep S/N curve with a narrow scatter band) for the Virgin, BF, and RP materials.