On the other hand, the theoretical predictions given by Equations (3) and (6) based on a
strain hardening material behavior over-predict the experimental mean loads although the differences are much reduced as compared to the previous cases.
The phase transition behavior from
strain hardening to strain softening appears gradually with the confining pressure increasing.
Comparison of the constant K specified in the material of the sheets of the material DC 04 with the measured values obtained for the examined materials of the F-M steels (Table 2) show that the constant K (K = 1052 - 1336 MPa) of all materials was higher that of a steel sheets DC 04 and the values of the
strain hardening exponent of materials produced by intercritical annealing were greater or comparable with the DC 04.
"We have found that the
Strain Hardening test delivers reproducible results which very nicely correlate with results of time-consuming traditional slow crack growth tests -- but in a much shorter time," says Frans Scholten, expert on material testing at Kiwa Technology.
The microstructure rearranges itself, creating
strain hardening.
Strain hardening consequentially allows for greater stress.
"Our new SabicVestolen A RELY products in combination with the
strain hardening method -- that measures their performance -- are key deliverables in Sabic's global strategy to supply the pressure pipe industry with breakthrough technologies," said Jean Engels, business manager HDPE Sabic.
Childs [5] worked on materials subjected to a range of thermal softening and
strain hardening and studied their FE simulations.
Fracture phenomenon during pull-out process is described in four stages, which are; pre-slip, slip, transition, and
strain hardening. The loads and displacements for each stage are presented in Table 1 and 2, columns (3) to (6) respectively.
Some types of AHSS have a higher
strain hardening capacity resulting in a strength-ductility balance superior to conventional steels.
The
strain hardening becomes more pronounced with increasing LCB-PP content.
The most interesting results, registered at such action on the investigated joints, are abnormal tensile properties and character of
strain hardening of a specimen, whereby main attention has to be paid to elongation of the specimen [8].
They combine good melt strength and draw-down ratio with sag resistance and
strain hardening. They are specifically recommended for extrusion blow molding, thermoforming, and blown film extrusion.
