Python API

GlassPly Class

class structuralglass.layers.GlassPly(t_min, t_nom=None, E=<Quantity(71.7, 'gigapascal')>)

A class to represent a glass ply, its thinkess (nominal and minimum allowable) and mechanical properties.

property E

The elastic modulus as Quantity [pressure].

Raises: ValueError – When set to a value less than 0MPa.

__init__(t_min, t_nom=None, E=<Quantity(71.7, 'gigapascal')>)

Constructor.

Parameters

t_min (Quantity [length]) – Min allowable thickness.
t_nom (Quantity [length], optional) – Nominal thickness, by default None (if using actual thickness)
E (Quantity [pressure], optional) – Elastic modulus, by default 71.7GPa

Raises

pint.DimensionalityError – If an input parameters do not meet the Quantity requirement.
TypeError – The provided nominal thickness is not a Quantity or None.
ValueError – Actual thickness/elastic modulus/nominal thickness cannot be less than zero.
ValueError – The provided nominal thickness could not be found in the lookup.

classmethod from_actual_thickness(t_act)

Class method to creating a GlassPly with an actual thickness.

Parameters: t_act (Quantity [length]) – Actual thickness.
Returns
Return type: GlassPly

classmethod from_nominal_thickness(t_nom)

Class method to creating a GlassPly with a nominal thickness.

Parameters: t_nom (Quantity [length]) – Nominal thickness.
Returns
Return type: GlassPly

property t_min

The minimum thickness as Quantity [length].

Raises: ValueError – When set to a value less than 0mm.

property t_nom

The nominal thickness as Quantity [length]

Raises: ValueError – When set to a value less than 0mm.

Interlayer Class

class structuralglass.layers.Interlayer(t, *, G=None, G_table=None)

A class to represent a glass interlayer (e.g. PVB or SG), and its mechanical properties. Rate dependent properties can be considered via the use of a product table or registered product name.

property G

The shear modulus as Quantity [pressure]. Interpolates linearly within the domain of the provided table.

Raises: ValueError – If a product table is being used and the reference temperature and/or duration are not set.

__init__(t, *, G=None, G_table=None)

Constructor

Parameters

t (Quantity [length]) – Interlayer thickness.
G (Quantity [pressure]) – Shear modulus for the case of a static layer, do not provide a G_table.
G_table (dict ((Quantity, Quantity): Quantity)) – Shear modulus table for the case of using an interlayer product table. The keys of the dict are tuples of units [temperature] and [time] for the interlayer temperature and load duration, respectively. The values of the dict are of units [pressure] for the shear modulus. Do not provide a G value.

Raises

ValueError – If neither G nor G_table are provided.
ValueError – If both G and G_table are provided.

property duration

The duration as Quantity [time].

Raises: ValueError – If no product table is provided.

classmethod from_product_table(t, product_name)

Class method for an Interlayer with a product table.

Parameters

t (Quantity [length]) – The thickness of the interlayer.
product_name (string) – The registred name of the product.

Returns

Return type

Interlayer

classmethod from_static(t, G)

Class method for an Interlayer with a static shear modulus.

Parameters

t (Quantity [length]) – The thickness of the interlayer.
G (Quantity [pressure]) – The shear modulus.

Returns

Return type

Interlayer

property temperature

The temperature as Quantity [temperature].

Raises: ValueError – If no product table is provided.

Interlayer Registry Functions

structuralglass.layers.register_interlayer_product(product_name, data)

Register new interlayer product table.

Parameters

product_name (str) – String identifier
data (dict ((Quantity, Quantity): Quantity)) – The tabulated data of the shear modulus that depends on temperature and load duration. The keys of the dict are tuples of units [temp] and [time]. The of the dict are of units [pressure]

Raises

ValueError – If the provided data table is not rectangular. E.g. if shear modulus values are given for (20degC, 3s) and (30degC, 10min), then values for (30degC, 3s) and (20degC, 10min) must also be provided.

structuralglass.layers.deregister_interlayer_product(product_name)

Deregister an existing interlayer product table.

Parameters: product_name (str) – Identifier

GlassType Class

class structuralglass.glass_types.GlassType(stress_surface, stress_edge, duration_factor, surf_factors, coef_variation=0.2)

A class that represents the stress factors in glass.

__init__(stress_surface, stress_edge, duration_factor, surf_factors, coef_variation=0.2)

Constructor.

Parameters

stress_surface (Quantity [pressure] i.e. [stress]) – The base allowable surface stress for the glass type.
stress_edge (Quantity [pressure] i.e. [stress]) – The base allowable edge stress for the glass type.
duration_factor (float) – The duration factor for the glass type.
surf_factors (dict (str, float)) – The allowable stress reduction factor for different surface treatments. e.g. “Acid etching” can reduce the allowable stress by 0.5.
coef_variation (float, optional) – The coefficient of variation for the glass type. This factor describes the statistical behavior of the failure stress. By default 0.2.

property coef_variation: The coefficient of variation.

design_factor(ratio)

Determines the design factor for the glass type based on a given failure ratio (e.g. 1/1000). This can be used to convert the average breaking stress to the stress corresponding with the failure ratio.

Parameters: ratio (float) – Failure ratio. E.g. 1/1000, 8/1000
Returns: The design factor for the glass type.
Return type: float

property duration_factor

The duration factor.

Raises: ValueError – When the duration factor is set less than 0.

classmethod from_abbr(abbr)

Class method to creating a GlassType from an abbreviation held in the registry.

Parameters: name (str) – Abbreviation.
Returns
Return type: GlassType
Raises: ValueError – When the registry does not contain the abbreviation.

classmethod from_name(name)

Class method to creating a GlassType from an identifier held in the registry.

Parameters: name (str) – Identifier.
Returns
Return type: GlassType
Raises: ValueError – When the registry does not contain the identifier.

load_duration_factor(time=<Quantity(3, 'second')>)

Determines the load duration factor for the glass type.

Parameters: time (Quantity [time], optional) – The load duration, by default 3*ureg.sec
Returns: Load duration factor to apply to the base stress.
Return type: float

prob_breakage_factor(ratio)

Determines the probability of breakage factor for the glass type based on a given failure ratio (e.g. 1/1000).

Parameters: ratio (float) – Failure ratio. E.g. 1/1000, 8/1000
Returns: Probability of breakage factor to apply to the base stress.
Return type: float

property stress_edge

The base allowable edge stress as Quantity [pressure].

Raises: ValueError – When the base allowable edge stress is set to less than 0MPa.

property stress_surface

The base allowable surface stress in Quantity [pressure].

Raises: ValueError – When the base allowable surface stress is set to less than 0MPa.

property surf_factors: The allowable stress reduction factor for different surface treatments as a dict of {str: float}

surf_treat_factor(surf_treat)

Looks up the reduction associated with a surface treatment

Parameters: surf_treat (str) – Looks up the factor for the surface treatment.
Returns: Surface treatment factor to apply to the base stress.
Return type: float

Glass Type Registry Functions

structuralglass.glass_types.register_glass_type(name, stress_surface, stress_edge, duration_factor, coef_variation, surf_factors, *, abbr=None)

Register a new glass type.

Parameters

name (str) – Identifier
stress_surface (Quantity [pressure] i.e. [stress]) – The base allowable surface stress for the glass type.
stress_edge (Quantity [pressure] i.e. [stress]) – The base allowable edge stress for the glass type.
duration_factor (float) – The duration factor for the glass type.
coef_variation (float, optional) – The coefficient of variation for the glass type. This factor describes the statistical behavior of the failure stress.
surf_factors (dict (str, float)) – The allowable stress reduction factor for different surface treatments. e.g. “Acid etching” can reduce the allowable stress by 0.5
abbr (str, optional) – Abbreviation, by default None

Raises

ValueError – If the name identifier already in use.
ValueError – If the abbreviation identifier already in use.

structuralglass.glass_types.deregister_glass_type(name)

Deregister an existing glass type.

Parameters: name (str) – Identifier

structuralglass.glass_types.get_glass_types_data()

Get a deep copy of the registry.

Returns: A dictionary of all the GlassType parameters (as dict), the keys are the identifiers.
Return type: dict (str, dict)

structuralglass.glass_types.get_abbr_data()

Get a deep copy of the abbreviation map.

Returns: A dictionary of the identifiers, the keys are the abbreviation.
Return type: dict (str, str)

GlassLiteEquiv Class

class structuralglass.equiv_thick_models.GlassLiteEquiv(ply)

An abstract class to represent the mechanical behavior of a liminate. Unique formulations of the mechanical behaviour are derived from this class.

property E: The elastic modulus for the formulation as a Quantity [pressure]

_E

Private attribute for the packages elastic modulus

Type: Quantity [pressure]

__init__(ply)

Constructor.

Parameters: ply (list (GlassPly and/or Interlayer)) – The list of glass layers and interlayers that form a laminate.

abstract _calc_equiv_thickness(): Abstract method to determine the equivalent thicknesses.

abstract _determine_package_E(): Abstract method to determine the packages elastic modulus.

_h_efs: dict (GlassPly, Quantity [length]): Private attribute for the effective thickness for stress

_h_efw: dict (GlassPly, Quantity [length]): Private attribute for the effective thickness for displacement.

abstract _validate(plys)

Abstract method to valadate the plys.

Parameters: plys (list (GlassPly and/or Interlayer)) –
Returns: True for a valid formulation. A mesage for an error.
Return type: (bool, str)

property h_efs: The equivalent laminate thickness for the stress in the associated plys as a dict (GlassPly, Quantity [length])

property h_efw: The equivalent laminate thickness for displacement as a Quantity [length]

property ply

A list of glass layers and interlayers that form a laminate as a list (GlassPly and/or Interlayer)

Raises: ValueError – If the provided list fails the formulations validation function.

Monolithic Method

class structuralglass.equiv_thick_models.MonolithicMethod(plys)

A basic/naive mechanical behavior that assumes the laminates effective thickness is the sum of the plys minimum thicknesses. This assumption applies to both stress and deflection effective thickness. This models validity decreases with load duration.

__init__(plys)

Constructor for a liminate’s behaviour.

Parameters: plys (list (GlassPly)) – The list of glass layers that form a laminate.

_calc_equiv_thickness()

Calculates the effective thicknesses.

The sum of the plys minimum thicknesses is used.

_determine_package_E()

Assign the elastic modulus for the formulation.

As the validation function is already checks the elastic modulus of all GlassPly are the same, take the 1st plys elastic modulus.

_validate(plys)

Validate the data in the plys.

Checks the list is only contains type GlassPly.
Checks the elastic modulus of all GlassPly are the same.

Parameters: plys (list (GlassPly)) –
Returns: True for a valid formulation. A mesage for an error.
Return type: (bool, str)

Non-Composite Method

class structuralglass.equiv_thick_models.NonCompositeMethod(plys)

A simple mechanical behavior that assumes the laminates effective thickness is:

for deflection: the square root of the minimum thicknesses squared

for stress: the cubed root of the minimum thicknesses cubed

This models assumes a non-composite behavior.

__init__(plys)

Constructor for a liminate’s behaviour.

Parameters: plys (list (GlassPly)) – The list of glass layers that form a laminate.

_calc_equiv_thickness()

Calculate the effective thicknesses.

The laminates effective thickness is for:

deflection: the square root of the sum of the minimum thicknesses squared

stress: cubed root of the sum of the minimum thicknesses cubed

_determine_package_E()

Elastic modulus for the formulation.

As the validation function is already checks the elastic modulus of all GlassPly are the same, take the 1st plys elastic modulus.

_validate(plys)

Method that validates the data in the plys.

Checks the list is only contains type GlassPly
Checks the elastic modulus of all GlassPly are the same.

Parameters: plys (list (GlassPly)) –
Returns: True for a valid formulation. A mesage for an error.
Return type: (bool, str)

Shear Transfer Coefficient Method

class structuralglass.equiv_thick_models.ShearTransferCoefMethod(plys, panel_min_dim)

A mechanical behavior that takes the shear modulus of the laminate into consideration. This method was originally proposed by Bennison-Wolfel and referenced in ASTM E1300. It is only valid for a two glass ply laminate. Ref literature for limitations.

__init__(plys, panel_min_dim)

Constructor for a liminate’s behaviour.

Parameters

plys (list (GlassPly and Interlayer)) – The list of glass layers and Interlayers that form a laminate.
panel_min_dim (Quantity [length]) – Minimum dimension of the rectangular panel

_calc_equiv_thickness()

Calculate the effective thicknesses.

This method was originally proposed by Bennison-Wolfel and referenced in ASTM E1300.

_determine_package_E(): Method to determine the elastic modulus for the formulation. As the validation function is already checks the elastic modulus of all GlassPly are the same, take the 1st plys elastic modulus.

_validate(plys)

Validate the data in the plys.

This formulation is only valid for plys with that are [GlassPly, Interlayer, GlassPly].

The GlassPly’s must have the same elastic modulus.

Parameters: plys (list (GlassPly and Interlayer)) – The list to be validated.
Returns: True for a valid formulation. A mesage for an error.
Return type: (bool, str)

property beta

The beta value of the formulation. A coefficient dependent on the boundary and loading conditions.

Returns
Return type: float

property panel_min_dim

The minimum dimension of the rectangular panel.

Returns
Return type: Quantity [length]
Raises: ValueError – If the minimum panel dimension is less than 0m.

IGUWindDemands Class

class structuralglass.demands.IGUWindDemands(buildup, wind_load, dim_x, dim_y)

A simplified method for IGU under wind load (short duration). The method uses stiffness based load sharing to distribute the wind load and equivalent thickness to determine stress and deflections.

property LSF: The load share factor for each package as a dict (GlassLiteEquiv, float)

__init__(buildup, wind_load, dim_x, dim_y)

Constructor.

Parameters

buildup (list (GlassLiteEquiv)) – The buildup.
wind_load (Quantity [pressure]) – The wind load on the IGU.
dim_x (Quantity [length]) – The x-dimensions of the plate.
dim_y (Quantity [length]) – The y-dimensions of the plate.

Raises

ValueError – If buildup contains duplicate objects, to avoid this use deep copy.
ValueError – If a mixture of effective thickness models is used. Only one model type should be used.

property buildup: The buildup as a list (GlassLiteEquiv).

property deflection: The deflection as a dict (GlassLiteEquiv, Quantity [pressure])

property dim_x

The dim_x as a Quantity [‘length’].

Raises: ValueError – If the dimension is less than 0 inch/mm

property dim_y

The dim_y as a Quantity [‘length’]

Raises: ValueError – If the dimension is less than 0 inch/mm

solve(): Runs the solver.

property stress: The stress as a dict (GlassPly, Quantity [pressure])

property wind_load: The wind load in Quantity [pressure].