Calculation of the direct stress due to warping
The direct stress due to warping is given by (Ref.[2] 7.4.3.2.3, Ref.[3])
with
|
Mw |
the bimoment |
|
wM |
the unit warping |
|
Cm |
the warping constant |
I sections
For I sections, the value of wM is given in the tables (Ref. [2], Tafel 7.87, 7.88). This value is added to the profile library. The diagram of wM is given in the following figure:
The direct stress due to warping is calculated in the critical points (see circles in figure).
The value for wM can be calculated by (Ref.[5] pp.135) :
|
b |
the section width |
|
hm |
the section height (see figure) |
U sections
For U sections, the value of wM is given in the tables as wM1 and wM2 (Ref. [2], Tafel 7.89). These values are added to the profile library. The diagram of wM is given in the following figure :
The direct stress due to warping is calculated in the critical points (see circles in figure).
Σ sections
The values for wM are calculated for the critical points according to the general approach given in Ref.[2] 7.4.3.2.3 and Ref.[8] Part 27.
The critical points for each part are shown as circles in the figure.