Bending Strain |
 
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Bending Strain |
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Bending strain in an element cross section is defined by the equation below, with reference to the Bending Strain Calculation figure below. Note that the maximum bending strain occurs at the outer surface of the cross section.
Bending Strain Calculation
where:
•
is the bending stress for an angle θ as defined in the figure above
•
and 
are the curvatures about the local y- and z-axes, respectively
• Do is the effective outer diameter
By default, Flexcom outputs the maximum bending strain occurring on the cross section. However, when you request a plot of bending strain, you can optionally specify a location around the element circumference where bending strain is to be computed. The location is specified in terms of an integer value (N) which corresponds to an angle θ, measured in degrees anti-clockwise from the local element cross-section y-axis. The table below indicates the variation of parameter N with θ for bending strain calculations.
Location Parameter for Bending Strain Calculations
θ° |
N |
0 |
1 |
45 |
2 |
90 |
3 |
135 |
4 |
180 |
5 |
225 |
6 |
270 |
7 |
315 |
8 |
Since maximum bending strain must occur on the riser outer surface, only values for n between 1 and 8 are required (or valid).
If you do not explicitly specify a location N, Flexcom outputs the maximum bending strain occurring on the cross section. The maximum value of 
can be found from the Equation above by setting 
. The value of θ corresponding to the maximum bending strain is given by:
(2)
Flexcom calculates maximum bending strain using the Equation above.
