Civil Engineering Reference
In-Depth Information
Fig. 3.16 The loading pro
le maximum stress applied in warp direction 8 kN/m (5 % of UTS).
Maximum stress applied in
fill direction 6 kN/m (4.28 % of UTS). Running time: 3,670 s (1 h)
range considered. Consequently, the material parameters which can be estimated on
the basis of these biaxial tests cannot be considered representative of the material
behaviour for higher stress regimes or near failure situations.
3.4.4.3 Data Considered
Due to the reduced number of European laboratories equipped with professional
biaxial apparatus for architectural fabrics and the complexity of the procedure, this
experiment involves only three laboratories which tested only one sample each. For
the comparison of the overall behaviour of the three testing apparatuses, experi-
mental data concerning the time elapsed [s], the applied force [kN/m] and the
material strain [%] has been considered.
In addition, in order to determine the precision of the parameters used in the
design phase, the procedure in use at FormTL has been applied to the four series of
experimental data. The comparison is based on the crimp interchange and the
stiffness in warp and weft direction.
3.4.5 Results
The overall behaviour of the four testing apparatus has been initially compared
overlapping the data of the complete loading pro
le. The aim of this initial eval-
uation is to offer an overview of the differences in the data trends and the biaxial
