Investigation on True Stress-Strain Curves of Flat and Corner Regions of Cold-Formed Section Using 3D Digital Image Correlation Method
Table 4
Mechanical parameters of true stress-strain curves.
Types of coupons
Specimens
(MPa)
(MPa)
(MPa)
Flat coupons
TW-1
262.033
0.0013
554.07
0.332
—
—
TW-2
255.463
0.0012
548.14
0.324
—
—
TW-3
262.68
0.0012
542.26
0.323
—
—
BW-1
255.13
0.0013
570.56
0.354
—
—
BW-2
266.04
0.0013
576.83
0.331
—
—
BW-3
262.63
0.0012
553.42
0.308
—
—
Corner coupons
TB-1
411.55
0.002
441.59
0.028
396.57
0.105
TB-2
384.96
0.002
458.03
0.039
384.67
0.128
TB-3
392.64
0.002
450.32
0.021
386.67
0.128
BB-1
404.35
0.002
451.08
0.029
406.28
0.103
BB-2
382.45
0.002
460.51
0.034
419.02
0.104
BB-3
414.21
0.002
451.09
0.029
414.09
0.102
Average values of flat coupons
260.66
0.0013
557.55
0.329
—
—
Average values of corner coupons
398.36
0.002
452.10
0.030
401.22
0.112
Improvements of average values
52.83%
61.54%
−18.91%
−90.88%
—
—
Note. (1) is the true yielding strength; (2) is the true yielding strain; (3) is the true ultimate strength; (4) is the corresponding true ultimate strain; (5) is the true fracture stress; and (6) is the true fracture strain.