ShellElement module

Classes for failure analyisis of shell element.

Revision: 1.0.0 $Date: 23/01/2023 17:32$

History

1.0.0 - Initial Class Creation

To Do:

So many

class ShellElement.ShellElemPshell(mid, thickness, matdata, stress)[source]

Bases: object

Class for failure analysis of isotropic materials (like aluminum arroy)

Examples:

Example of calculation of Margin of Safety.

>>> elem = ShellElemPshell(mids, thetas, thicknesses, matdata, stress)
>>> elem.calc_ms()
>>> elem.get_ms()

__init__(mid, thickness, matdata, stress)[source]

ShellElemPshell Class Initialization.

Parameters

mid (int) – material id
thickness (float) – thickness
matdata (dict) – dictionary of material properties
stress (pd.DataFrame) – stress

Returns

None

Note

Thicknesses are divided by 2. This is because the thickness of SMEAR model represents the total thickness of stiffened panel which is assumed to have an EA ratio of 1:1. In the case of DISCRETE model, there is no need to divide the thicknesses.

Note

Pitch of stringer is hard coded. It should be an input parameter. Can someone please refactor it?

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms()[source]

Administrator of MS calculation.

Comment and uncomment lines depending on your case

Parameters: None –
Returns: None

Note

Selection of failure should be an input. Can someone please refactor it?

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_buckling_c()[source]

Calculate MS for axial buckling failure.

Parameters: None –
Returns: margin of safety
Return type: ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_mises()[source]

Calculate MS for Mises criteria.

Parameters: None –
Returns: MS for Mises criteria
Return type: ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

get_ms()[source]

Output function of MS data

Parameters: None –
Returns: dictionary of MSs
Return type: ms (dict)

Documentation last updated: Jan. 23, 2023 - Shugo Date

class ShellElement.ShellElemPcomp(mids, thetas, thicknesses, matdata, stress)[source]

Bases: object

Class for failure analysis of orthotropic materials (like composite materials)

Examples:

Example of calculation of Margin of Safety.

>>> elem = ShellElemPcomp(mids, thetas, thicknesses, matdata, stress)
>>> elem.calc_ms()
>>> elem.get_ms()

__init__(mids, thetas, thicknesses, matdata, stress)[source]

ShellElemPcomp Class Initialization.

Parameters

mids (list) – material ids in each layer
thetas (list) – orientation angles in each layer
thicknesses (list) – thickness of each layer
matdata (dict) – dictionary of material properties
stress (pd.DataFrame) – stress

Returns

None

Note

Thicknesses are divided by 2. This is because the thickness of SMEAR model represents the total thickness of stiffened panel which is assumed to have an EA ratio of 1:1. In the case of DISCRETE model, there is no need to divide the thicknesses.

Note

Pitch of stringer is hard coded. It should be an input parameter. Can someone please refactor it?

Documentation last updated: Jan. 23, 2023 - Shugo Date

setup()[source]

set up for calculating Margin of Safety.

This function calculate

In-plane stiffness matrix
Homogenized in-plane stiffness matrix $\pmb{A}$
Homogenized bending stiffness matrix $\pmb{D}$
Averaged stress in thickneswise direction
Strain in symmetric plane corresponding to the averaged stress

Parameters: None –
Returns: None

Note

In the current version, stacking sequence is fixed and thickness of each lamina is sized. Therefore, bending stiffness is greatly affected by the setting of the stacking sequence. For this reason, once the homogenized in-plane stiffness matrix A is calculated, the bending stiffness matrix is calculated. In the future, it is desirable to formulate the design problem that can calculate bending stiffness straightforwardly.

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_sig_bar_eps_sym()[source]

Calcration of averaged stress and strain on symmetric plane.

Rotate stresses vectors in the direction of the element coordinate system. Averaged stress vector is calculated using rotated stress vectors. After that, strain vectors on symmetric plane is calculated by Classical Laminated Theory.

Parameters: None –
Returns: None

Note

Plane stress is assumed in the function. Therefore, the modeling is strictly different from MITC4. You may have the option to verify or modify the model.

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_qmat(mat, qmat, theta)[source]

Calculation of constitutive equation of plate $\pmb{Q}$.

Parameters

mat (dict) – dictionary of material properties
qmat (ndarray) – np array of $\pmb{Q}$ matrix
theta (float) – orientation angle in the layer

Returns

None

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_mat(s, mat)[source]

Calculation of Classical Laminate Theory.

Matrix is switched parametrically

s = 1. : $\pmb{A}$ matrix
s = 2. : $\pmb{B}$ matrix
s = 3. : $\pmb{D}$ matrix

Parameters

s (int) – index to switch $\pmb{A},~\pmb{B},~\pmb{D}$
mat (ndarray) – np array to store a matrix

Returns

None

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms()[source]

Administrator of MS calculation.

Comment and uncomment lines depending on your case

Parameters: None –
Returns: None

Note

Selection of failure should be an input. Can someone please refactor it?

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_buckling_c()[source]

Calculate MS for axial buckling failure.

Parameters: None –
Returns: margin of safety
Return type: ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_buckling_s()[source]

Calculate MS for shear buckling failure.

Parameters: None –
Returns: margin of safety
Return type: ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_buckling_cs(ms_c, ms_s)[source]

Calculate MS for combined buckling failure.

Parameters

ms_c (float) – MS for axial buckling
ms_s (float) – MS for shear buckling

Returns

MS for combined buckling

Return type

ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_strain_oht()[source]

Calculate MS for OHT strain criteria.

Parameters: None –
Returns: MS for OHT strain criteria
Return type: ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_strain_ohc()[source]

Calculate MS for OHC strain criteria.

Parameters: None –
Returns: MS for OHC strain criteria
Return type: ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_strain_cai()[source]

Calculate MS for CAI strain criteria.

Parameters: None –
Returns: MS for CAI strain criteria
Return type: ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_chris_f(stress, mat, theta)[source]

Calculate MS for fiber-dominant Christensen’s criteria.

Parameters

stress (dict) – in-plane stress vector of shell elements
mat (dict) – dictionary of material properties
theta (float) – orientation angle in the layer

Returns

MS for fiber-dominant Christensen’s criteria

Return type

ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

calc_ms_chris_m(stress, mat, theta)[source]

Calculate MS for matrix-dominant Christensen’s criteria.

Parameters

stress (dict) – in-plane stress vector of shell elements
mat (dict) – dictionary of material properties
theta (float) – orientation angle in the layer

Returns

MS for matrix-dominant Christensen’s criteria

Return type

ms (float)

Documentation last updated: Jan. 23, 2023 - Shugo Date

get_ms()[source]

Output function of MS data

Parameters: None –
Returns: dictionary of MSs
Return type: ms (dict)

Documentation last updated: Jan. 23, 2023 - Shugo Date