60. plugins.section2d
— Some functions operating on 2D structures.¶
This is a plugin for pyFormex. (C) 2002 Benedict Verhegghe
See the Section2D example for an example of its use.

class
plugins.section2d.
PlaneSection
(F)[source]¶ A class describing a general 2D section.
The 2D section is the area inside a closed curve in the (x,y) plane. The curve is decribed by a finite number of points and by straight segments connecting them.
60.1. Functions defined in module plugins.section2d¶

plugins.section2d.
sectionChar
(F)[source]¶ Compute characteristics of plane sections.
The plane sections are described by their circumference, consisting of a sequence of straight segments. The segment end point data are gathered in a plex2 Formex. The segments should form a closed curve. The zvalue of the coordinates does not have to be specified, and will be ignored if it is. The resulting path through the points should rotate positively around the z axis to yield a positive surface.
The return value is a dict with the following characteristics:
 L : circumference,
 A : enclosed surface,
 Sx : first area moment around global xaxis
 Sy : first area moment around global yaxis
 Ixx : second area moment around global xaxis
 Iyy : second area moment around global yaxis
 Ixy : product moment of area around global x,yaxes

plugins.section2d.
extendedSectionChar
(S)[source]¶ Computes extended section characteristics for the given section.
S is a dict with section basic section characteristics as returned by sectionChar(). This function computes and returns a dict with the following:
 xG, yG : coordinates of the center of gravity G of the plane section
 IGxx, IGyy, IGxy : second area moments and product around axes through G and parallel with the global x,yaxes
 alpha : angle(in radians) between the global x,y axes and the principal axes (X,Y) of the section (X and Y always pass through G)
 IXX, IYY : principal second area moments around X,Y respectively. (The second area product is always zero.)