Stringer SEs (structmanager.ses.stringer)

class structmanager.ses.stringer.Stringer(name, *eids)

Bases: structmanager.ses.ses.SE1D

Each cross-section (profile) dimension is defined according do the PBARL entry of Nastran’s Quick Reference Guide.

Attributes

profile (str)

Z_t - Z section defined with one variable: t (variable): profile thickness b (constant): flange width h (constant): height Z_t_b - Z section defined with two variables: t (variable): profile thickness b (variable): flange width h (constant): height Z_t_b_h - Z section defined with three variables: t (variable): profile thickness b (variable): flange width h (variable): height Z_tf_tw_b_h - Z section defined with four variables: tf (variable): flange thickness tw (variable): web thickness b (variable): flange width h (variable): height B_t - Blade section defined with one variable: t (variable): thickness h (constant): height L (constant): length B_t_h - Blade section defined with two variables: t (variable): thickness h (variable): height L (constant): length The stringer’s attributes will vary from one profile to another.

Methods

constrain_buckling([method, ms])	Add a buckling constraint
create_dvars()

constrain_buckling(method=1, ms=0.1)

Add a buckling constraint

Parameters:

method : int, optional

Select one of the following methods for buckling calculation:

For profile in [‘Z_t’, ‘Z_t_b’ or ‘Z_t_b_h’]:

• 1 : Bruhn’s method for Channel- and Z-section stiffeners. From

  Fig. C6.4 for tw=tf (thickness web = thickness flange) - considers only compressive loads - no plasticity correction has been implemented

For profile in [‘B_t’, ‘B_t_h’]:

• 1 : Bruhn’s method for combined shear and compression, from

  Chapter C5.11. - disconsiders bending effects - assumes 3 edges simply supported with one free unloaded

  edge.

  • no plasticity correction has been implemented

ms : float, optional

Minimum margin of safety to be used as constraint.