Genesis (structmanager.genesis)

This module contains useful functions for exporting optimization models to GENESIS.

class structmanager.genesis.genesis.Genesis

GENESIS optimization model

This class corresponds to an optimization model.

Attribute	Description
dvprops	dict of DVPROP3 objects
deqatns	dict of DEQATN objects
dtables	dict of DTABLE
dresps	dict of DRESP1 or DRESP23 objects
dcons	dict of DCONS objects
dvars	dict of DVAR objects
dvar_codes	dict classifying the DVAR objects by their unique codes
dlinks	dict of DLINK objects
newprops	dict with different NASTRAN cards, see reset_newprops()
nodal_displ	dict with the nodal displacements constraints as detailed in nodal_displ_from_excel()
loads_list	list containing the load cases’ ids
spcs_list	list containing the single point constraint id for each load case
num_cycles	int indicating the number of design cycles
outputdir	str path to the output directory
genesisfile	file handler to GENESIS’s output file
nastranfile	file handler to NASTRAN’s output file

Methods

add_dvprop(*args)
constrain_pbar(pid, name, rtype, eltype, ...)	Add constraints to all stress recovery points of a bar property.
constrain_pshell(pid, cname, rtype, allow_C, ...)	Add constraints to the bottom and top faces of a shell property.
constrain_two_vars(var1, var2, maxdiff)	Constraint two vars in order to keep a maximum relative difference
create_dobj()	Create the design objective.
create_dvars()	Create the design variables.
create_topometric_data()
dlinks_from_excel(xls_file)	Read links between variables from an Excel file.
merge_temp_files()	Merge the temporary file handlers into the final input file.
nodal_displ_from_excel(xls_file)	Create nodal displacement constraints based on an Excel file.
pickle_dump(path)
pickle_load(path)
print_model()	Print the whole model.
reset_newprops()	Reset the dictionary newprops.
set_output_file(path)	Define the data related to the output file.
simx_create_output_file()
simx_export_nastran_file()

constrain_pbar(pid, name, rtype, eltype, allow_C, allow_T)

Add constraints to all stress recovery points of a bar property.

Parameters:

pid : int

Property id.

name : str or list

The name of the constraint, as described in output_codes, with only the prefix ('Shear', 'Normal', etc).

rtype : str

The type of response. For bar elements it is usually 'STRESS'.

eltype : str

The section type: 'RECT', 'CIRCLE', etc.

allow_C : float

The allowable for compression.

allow_T : float

The allowable for tension.

constrain_pshell(pid, cname, rtype, allow_C, allow_T)

Add constraints to the bottom and top faces of a shell property.

Parameters:

pid : int

Property id.

cname : str or list

The name of the constraint, as described in output_codes, without the sufix 'Bottom' or 'Top'.

rtype : str

The type of response. For shells it is usually 'STRESS'.

allow_C : float

The allowable for compression.

allow_T : float

The allowable for tension.

constrain_two_vars(var1, var2, maxdiff)

Constraint two vars in order to keep a maximum relative difference

Parameters:

var1, var2 : int or str

The variables id (int) or code (str).

maxdiff : float

The maximum relative difference that ‘var1’ and ‘var2’ must respect.

create_dobj()

Create the design objective.

create_dvars()

Create the design variables.

The method DVPROP3.create_dvar() of each property contained in the dictionary dvprops is called.

dlinks_from_excel(xls_file)

Read links between variables from an Excel file.

The Excel file should have the following format:

.	col j	col j+1	col j+2	col j+3	col j+4	col j+5	col j+6	col j+7
row i	DLINK
row i+1
row i+2	dvar	c0	c	ivar1	c1	ivar2	c2	...
row i+3	LP.1.1			LS.1.1	0.4	LS.1.2	0.6	...

where the relative position between the cell with DLINK and the others must be held.

Parameters:

xls_file : str

The full path of the Excel file.

merge_temp_files()

Merge the temporary file handlers into the final input file.

The file handlers contained in the attributes genesisfile and nastranfile are used to write a unique output file given by the attribute datname.

nodal_displ_from_excel(xls_file)

Create nodal displacement constraints based on an Excel file.

This function reads the xls file with nodal displacement constraints and returns a dictionary with the format:

nd = {load_case_id1 : {grid_1 : {output : [minvalue, maxvalue],
                       grid_2 :  output : [minvalue, maxvalue],
                       grid_3 :  output : [minvalue, maxvalue]}}
      load_case_id2 : {grid_1 : {output : [minvalue, maxvalue],
                       grid_3 :  outout : [minvalue, maxvalue]}}}

where minvalue and maxvalue are the minimum and maximum displacement values.

Parameters:

xls_file : str

The full path to the Excel file.

Returns:

output : str

A string with one of the values:

• 'Translation X'
• 'Translation Y'
• 'Translation Z'
• 'Rotation X'
• 'Rotation Y'
• 'Rotation Z'
• 'Translation Total'
• 'Absolute X'
• 'Absolute Y'
• 'Absolute Z'

print_model()

Print the whole model.

reset_newprops()

Reset the dictionary newprops.

This dictionary contains NASTRAN property cards that should be created along with the optimization model.

The supported cards are those corresponding to the classes defined in cards_solver.

set_output_file(path)

Define the data related to the output file.

The output directory is estimated based on path.

Parameters:

path : str

The full path of the output file.

Optimization cards (structmanager.genesis.cards_opt)

Many input cards related to the optimization problem are wrapped in this module. The input cards more related to the solver are contained in module structmanager.genesis.cards_solver.

Classes

structmanager.genesis.cards_opt.DCONS(...)	Design constraint
structmanager.genesis.cards_opt.DEQATN(eq)	Equation to calculate customized responses
structmanager.genesis.cards_opt.DLINK(...[, ...])	Link between design variables
structmanager.genesis.cards_opt.DOBJ(drespid)	Design objective
structmanager.genesis.cards_opt.DRESP1(...)	Design response DRESP1
structmanager.genesis.cards_opt.DRESP2(...)	Design response DRESP2
structmanager.genesis.cards_opt.DRESP3(...)	Design response DRESP3
structmanager.genesis.cards_opt.DSPLIT(...)	Defines a region for topometry optimization.
structmanager.genesis.cards_opt.DTABLE([...])	Design Table used to define many constants
structmanager.genesis.cards_opt.DVAR(label, ...)	Design Variable
structmanager.genesis.cards_opt.DVPROP3(...)	Design Variable-to-Property relation

class structmanager.genesis.cards_opt.DCONS(drespid, lid_lb_ub, stress_type)

Design constraint

Attributes

Methods

print_card

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DEQATN(eq)

Equation to calculate customized responses

Parameters:

eq : str

A string containing the equation. For example, the following equation:

\[T(x_1, x_2, x_3) = \sqrt{x_1^2 + x_2^2 + x_3^2}\]

can be written as:

eq = 'T(x1,x2,x3)=SQRT(x1**2+x2**2+x3**2)'

Notes

Note

The DEQATN.print_card() method will split the equation, when necessary, in order to keep the limit length up to 62 characters in the first line, and 70 characters for the subsequent lines.

Methods

print_card

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DLINK(dep_var, dvi_ci, c0=0.0, cmult=1.0)

Link between design variables

DLINK creates links among variables using the form:

\[dvar_{dependent} = c_0 + c_{mult} \times (c_1 \times {dvar}_1 + c_2 \times {dvar}_2)\]

where:

• dvar_{dependent} is the dependent variable
• {dvar}_i the i^{th} design variable
• c_0 is a constant
• c_{mult} is a common multiplier
• c_i is an individual multiplier for {dvar}_i

Parameters:

ddvid : int

Dependent design variable identification number.

c0 : float

Constant term.

cmult : float

Constant multiplier.

idvs : list

The independent variables.

cs : list

The multipliers for each variable.

Notes

Be sure that no dependent variables are being used as independent variables.

By default c0 = 0 and cmult = 1.

The values of dvi and ci are inputed as follows:

indep_dv_c = [dv1, c1, dv2, c2, ...]
indep_dv_c = [1000000, 1., 1000001, 1., ...]

Methods

print_card

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DOBJ(drespid)

Design objective

Methods

defaults
print_card

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DRESP1(label, rtype, ptype, region, atta, atti)

Design response DRESP1

Parameters:

label : str

User defined label.

rtype : str

Response type (‘DISP’, ‘STRESS’, ‘FREQ’ etc).

ptype : str

If ptype='ELEM' the ATTi are element IDs, if ptype='PSHELL' etc the ATTi are property IDs (see design manual for more info).

region : int

Region identifier for constraint screening.

atta : int

Displacement component number, item number or eigenvector component.

atti : list

Grid, spoint, field point, property, element or material ids.

Methods

print_card

print_card(file)

Print the corresponding input card

class structmanager.genesis.cards_opt.DRESP2(label, eqid, region=None)

Design response DRESP2

Define equation responses that are used in the design, either as an objective function or as constraints.

Parameters:

label : str

User-defined label.

eqid : int

DEQATN entry identification number.

region : int or None, optional

Region used for constraint screening.

Notes

To add variables, table entries or other DRESP1 responses use the methods: add_dvar(), add_dtable() and add_dresp1().

Methods

add_dresp1
add_dtable
add_dvar
print_aux
print_card

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DRESP23

Base class for DRESP2 and DRESP3

Methods

add_dresp1
add_dtable
add_dvar
print_aux

class structmanager.genesis.cards_opt.DRESP3(label, libid, region=None)

Design response DRESP3

Define use-subroutine or built-in responses that can be used in the design either as constraint or as an objective.

Parameters:

label : str

User-defined label.

libid : int

Library identification number or a built-in function name (see design manual).

region : int or None, optional

Region used for constraint screening.

Notes

To add variables, table entries or other DRESP1 responses use the methods: add_dvar(), add_dtable() and add_dresp1().

Methods

add_dresp1
add_dtable
add_dvar
print_aux
print_card

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DSPLIT(label, ptype, pid, cvalue, cid, manufact_cons_input)

Defines a region for topometry optimization.

Parameters:

label : str

User defined name for output purposes.

ptype : str

Designable region type (‘PROD’, ‘PBAR’, ‘PSHELL’ etc).

pid : int

Property identification number.

cvalue : int

Desired maximum number of elements per group.

cid : int

Coordinate system identification number.

manufact_cons_input : list

A list of strings defining the type1, type2 and type3 of fabrication constraints.

Methods

defaults
manufact_cons
print_card

manufact_cons()

Create manufacture constraints following GENESIS Design Reference

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DTABLE(input_dict={})

Design Table used to define many constants

Hints:

• There can be any number of DTABLE entries in the bulk data.
• The user must avoid repeated labels for constants
• The constant label must be <= 8 characters.

All values for the constants must be of the ‘Real’ type. Ex:

input_dict={'c1':1. , 'c2':2., 'max8char':999.}

Methods

print_card

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DVAR(label, init, lb, ub, dvsid, dvprop=None, code=None)

Design Variable

Parameters:

label : str

User-supplied name for printing purposes.

init : float

Initial value.

lb : float

Lower bound.

ub : float

Upper bound.

dvprop : DVPROP3 or None, optional

The corresponding design variable-to-property relation.

code : str or None, optional

An additional code to identify the design varible.

Methods

defaults
print_card
show_card

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

class structmanager.genesis.cards_opt.DVPROP3(sizing_data, pid, ptype, eltype, dvar_labels=None, dvar_codes=None)

Design Variable-to-Property relation

This is a wrapper for the DVPROP3 card in Genesis.

Parameters:

sizing_data : TODO

The sizing data for this entry.

id : :

Methods

create_dvars
defaults
print_card

create_dvars()

Create the design variables for the current DVPROP3

print_card(file)

Print the corresponding input card

Parameters:

file : file

File object with a write() method.

Optimization cards (feopt.genesis.cards_solver)

Many input cards related to the finite element solver are wrapped in this module.

class structmanager.genesis.cards_solver.PBARL(id, mid, library, type, d_list, nsm=0.0)

Pre-defined sections for bar elements

Attribute	Description
id	int - property id
mid	int - material id
library	str - the default library used to calculate the section properties ('CSLIB1', etc)
d_list	list - design variables
type	str - section type ('RECT', etc)
nsm	float - non-structural mass in [mass unit]/[metric unit]

Methods

add_dvprop
constrain_pbar
constrain_pshell
constrain_two_vars
create_dobj
create_dvars
create_topometric_data
dlinks_from_excel
merge_temp_files
nodal_displ_from_excel
pickle_dump
pickle_load
print_card
print_model
reset_newprops
set_output_file
simx_create_output_file
simx_export_nastran_file

print_card(file)

Prints the corresponding input card

Parameters:

file : file

File object with a write() method.

Sizing data (feopt.genesis.sizing_data)

In this module it is defined the dictionary SDATA containing the definition of the sizing variables for each property accordingly to GENESIS Analysis Manual (vol01).

It should be used as SDATA[ptype][etype], where:

• ptype is 'PSHELL', 'PBARL', etc
• etype for a shell is 'SOLID', 'SAND', etc
• etype for a bar is 'SQUARE', 'TUBE', 'Z', etc

The currently available values are: