Stress net-section

Fig. 8.93 Observed and calculated values of the threshold net section stresses for stress corrosion cracking of a C-Mn steel after various prior deformations and ageing treatments...

Figure 7, Temperature dependence of failure stresses in Instron three-point bend tests on Vs inch notched Izod bars cut from (a) extruded polycarbonate sheet and (b) compression molded block polymer B. Crosshead rate = 0,02 inch /min. Span = 2 inches, o = net section stress = force/net cross-section at notch root, O, Craze initiation , ductile failure X, brittle failure ...

Dwell Faligue or Creep Net Section Stress (MPa) Time Dwell Fati ue CrecD Residual Apparent Re-Load Modulus (13-56 MPa) (GPa)... 

The net section stress, accounting for the loss of section caused by the damage, exceeds the ultimate strength of the material. 

As for the LEFM approach, the EWF data must be checked for validity. The maximum net section stress a max (=Fmaxflt) in the ligament is supposed to depend very little on ligament length it should satisfy the following relationship (24) ... 

FIG. 11—Effect of loading method and extent of cracking or corrosion pattern on average net section stress (see ASTM G 49). 

In the centre of the specimen at the position of the notch, the stress is smaller than the net-section stress (Tnss- The reason for this is that the total force transferred through the cross section does not change and that the stress at the notch root is larger than (Tnss-... 

In the context of notches, the stress concentration is always related to the net-section stress stress concentration at the notch root has to be compared to the nominal stress far away from the notch or, more precisely, (Tnooi infinitely far away from the notch), the increase in stress due to the reduced cross section and the stress concentration at the notch root have to be multiplied. 

Imagine the shaft to be loaded in tension with a force of 1200kN. Far away from the notch, the stress is thus 152.8 MPa. Due to the smaller cross section at the notch position, the net-section stress is <7nss = 188.6 MPa. If the material is linear elastic, as we assumed so far in this section, and use Kt fa 2.7, the maximum stress is [Pg.121]

If we assume that the net-section stress apss is smaller than the yield strength, we can use Hooke s law Snss = o nss/E to derive Neuber s rule... 

Now it is possible to solve the integral (10.36) and it will be done, for simplicity, by a finite differences integration procedure. To that end, the total crack growth Aa = af— Go is divided into a convenient number of parts such as, for example, 30 so that in each single elementary interval da — Aa/iO the net section stress <7 e, and the corresponding stress intensity factor AK/ are considered constant... 

Fig. 15.9 Central crack panel wedge loaded with a constant load and trend of and net section stress (modified Irom [8])...

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