(1) is proposed for the end correction to interface slip.
A value of the order of 0.2 mm was calculated as end correction for the geometry and material properties of the SCC girders studied in this paper.
The results are below the experimental data, and this is mainly due to the inability of a viscous model to capture the end correction (for L/D = 0).
As in our recent work , the present viscoelastic results are unique in reaching levels of apparent shear rates as high as 1000 [s.sup.-1] and showed the importance of including long lengths to fully relax the viscoelastic stresses for highly viscoelastic polymer melts, such as this LDPE, in order to capture the end correction.
We also have other treatments such as split end correction
, hair-fall treatment, cuts,
To obtain the real shear stress at the wall of the capillary, [[Tau].sub.w], the Bagley end correction was adopted:
where e is the end correction, R is the radius of the capillary and [Delta][P.sub.ent] is the entrance pressure drop.
* the end correction factor is negligible as the [1.sub.c]/[d.sub.c] ratio of the capillary is 40.
Also, the low L/D ratio of the die makes the data subject to an unassessed end correction. The differences in the MFI may not be reflected in the injection molding behavior of these blends.
Boger and Binnington (4) found that the increase in the end correction
with shear rate is due to the shear thinning effects of the fluid.
To obtain an estimate of the validity of the end corrections
under ideal test conditions, boundary element models were constructed using typical duct cross sections and lengths for ARI 260 testing.
Ziegel, "Estimation of end corrections
in capillary flow," paper at Society of Rheology, Nov.