pystran.section module#

Define section dictionaries.

A section defines material properties, geometrical properties, such as the second moment of area, and also orientation of the cross section profile.

pystran.section.beam_2d_section(name, E=0.0, A=0.0, I=0.0, rho=0.0, CTE=0.0)[source]#

Define 2d beam section.

The parameters can be defined either as regular list of values or variables, or in the keyword=value style.

Parameters:

  • E – Young’s modulus.

  • A – Cross-sectional area.

  • I – Central moment of inertia of the cross-section about the \(y\) coordinate axis (i.e. the axis perpendicular to the plane of the bending, \(x-z\)).

  • rho – Mass density.

  • CTE – Coefficient of thermal expansion.

Returns:

Dictionary that holds the data for this section.

Return type:

Dict

Examples

>>> sbar = section.beam_2d_section("sbar", E=E, rho=rho, A=A, I=Iy)
pystran.section.beam_3d_section(name, E=0.0, G=0.0, A=0.0, Ix=0.0, Iy=0.0, Iz=0.0, J=0.0, rho=0.0, xz_vector=(0, 0, 1), CTE=0.0)[source]#

Define 3d beam section.

The parameters can be defined either as regular list of values or variables, or in the keyword=value style.

Parameters:

  • E – Young’s modulus.

  • G – Shear modulus.

  • A – Cross-sectional area.

  • rho – Mass density.

  • A – Cross-sectional area.

  • Ix – Central moment of inertia of the cross-section about the local \(x\).

  • Iy – Central moment of inertia of the cross-section about the local \(y\).

  • Iz – Central moment of inertia of the cross-section about the local \(z\).

  • J – St Venant torsion constant.

  • xz_vector – Vector that lies in the local \(x-z\) coordinate plane.

  • CTE – Coefficient of thermal expansion.

Returns:

Dictionary that holds the data for this section.

Return type:

Dict

Examples

>>> sb = section.beam_3d_section("sb", E=E, G=G, A=A, Ix=Ix, Iy=Iy, Iz=Iz, J=J)
pystran.section.circular_tube(innerradius, outerradius)[source]#

Calculate cross section characteristics for a hollow circle (tube).

Parameters:

  • innerradius – Inner radius of the tube.

  • outerradius – Outer radius of the tube.

Returns:

Area, moments of inertia and torsion constant.

Return type:

tuple of A, Ix, Iy, Iz, J

pystran.section.i_beam(H, B, tf, tw)[source]#

Calculate cross section characteristics for an I-beam.

Parameters:

  • H – Height of the cross section, i.e. dimension along z. The axis parallel to the flanges is \(y\), the axis parallel to the web is \(z\).

  • B – Width of the flanges.

  • tf – Thickness of the flanges.

  • tw – Thickness of the web.

Returns:

Area, moments of inertia and torsion constant.

Return type:

tuple of A, Ix, Iy, Iz, J

pystran.section.rect_tube(H, B, th, tb)[source]#

Calculate cross section characteristics for an rectangular tube.

Parameters:

  • H – Height of the cross section, i.e. dimension along \(z\).

  • B – Width of the cross section, i.e. dimension along \(y\).

  • th – Thickness of the walls along the height.

  • tb – Thickness of the walls along the width.

Returns:

Area, moments of inertia and torsion constant.

Return type:

tuple of A, Ix, Iy, Iz, J

pystran.section.rectangle(H, B)[source]#

Calculate cross section characteristics for a solid rectangle.

Parameters:

  • H – Height of the cross section, i.e. dimension along \(z\).

  • B – Width of the cross section, i.e. dimension along \(y\).

Returns:

Area, moments of inertia and torsion constant.

Return type:

tuple of A, Ix, Iy, Iz, J

Define a rigid link section.

The parameters can be defined either as regular list of values or variables, or in the keyword=value style.

Parameters:

Gamma – Diagonal matrix of penalty coefficients; zero coefficient means the degrees of freedom are not linked.

Returns:

Dictionary that holds the data for this section.

Return type:

Dict

Examples

>>> sr = section.rigid_link_section("sr", Gamma=1e8 * numpy.diagflat([1.0, 1.0, 1.0]))
pystran.section.spring_section(name, kind, direction, stiffness_coefficient=1.0)[source]#

Define a section for a general extension or torsion spring.

The parameters can be defined either as regular list of values or variables, or in the keyword=value style.

Parameters:

  • kind – Either "extension" or "torsion". The connected joints either react to displacement or to rotation.

  • direction – The spring acts along this direction for extension springs, or about this direction for torsion springs.

  • stiffness_coefficient – Stiffness coefficient of the spring.

Returns:

Dictionary that holds the data for this section.

Return type:

Dict

Examples

>>> section.spring_section("EXT_A", "extension", [0, 1, 0], K),
pystran.section.truss_section(name, E=0.0, A=0.0, rho=0.0, CTE=0.0)[source]#

Define truss section.

The parameters can be defined either as regular list of values or variables, or in the keyword=value style.

Parameters:

  • E – Young’s modulus.

  • A – Cross-sectional area.

  • rho – Mass density.

  • CTE – Coefficient of thermal expansion.

Returns:

Dictionary that holds the data for this section.

Return type:

Dict

Examples

>>> s1 = section.truss_section("steel", E, A)

>>> sr = section.truss_section("sr", E=E, A=Ar, CTE=0.0)

>>> sr = section.truss_section("sr", E=E, A=Ar)