Under bending test, load-deflection curve of the bolt specimens indicated large ductility index and clear strain hardening after reaching the proportional limit load.
Within each load-slip curve, connection yield load and ductility index are defined as follows: Yield load is the load at the intersection point between the curve and an offset line having a slope equals to the initial slope of the curve but this line is shifted by a slip of 5% of bolt diameter as shown in Figure 6 [16,17]; Ductility index is defined as ratio between the slip at load decreased by 20% from its maximum load (or at the ultimate load when the curve never reaches 20% load decrease after its maximum load) and the slip at yield load.
Again, these load-slip curves are analyzed to obtain their connection yield loads and ductility indexes as can be seen in Table 3, where it is well observed that ductility index of the two-bolt connections is significantly lower than that of the single-bolt connections (specimens with end distance of 5d).
In order to identify the flexural characteristics of beam reinforced with aramid fiber sheets, 4 RC beams to which recycled aggregates were mixed were produced, and after applying unreinforced specimen, specimen reinforced at the bottom part, specimen reinforced at the bottom part and both end parts, and specimen reinforced at the bottom part and side part, respectively, the flexural performance of aramid fiber sheet RC beam was identified through analysis of the load-bending curve, concrete crack and fiber sheet rupture pattern, yield strength, maximum load, and ductility index
measured in the experiment.
The ductility of the columns is assessed by the use of a ductility index (DI) as following (Lin, Tsai 2001):
The ductility index, Eqn (12), is also used to study the effect of steel wall thickness on the ductility of the columns.
Beaumont and others define an adimensional parameter called ductility index
used to establish the impact performances of different materials with similar geometries.
The ductility index was calculated according to Eq.
The Charpy impact strength, the perforation energy and the ductility index of long fiber reinforced composite are much higher than in case of the short fiber reinforced one.
It is also clear that, strengthening with externally bonded GFRP strip in different layers to tension face of precracked and uncracked beams result in reduce the beam ductility index
(ratio between deflection at failure and its deflection at yield) than that of the control beam.
The ductility index of the n*-notched foamed samples was slightly higher than that of unfoamed samples, whereas the opposite is true with the bs- and unnotched foamed samples.
Finally, the ductility index of the supersaturated samples remained the same as that of the neat samples.