structuralglass
structuralglass is a python package for facade/enclosure designers and engineers who design structural glass. This open-source package provides a collection of utilities that a designer will find useful to answer a variety of design questions, for example:
ask questions about common laminate properties and compare performance.
build a personal library of manufacturers’ data.
perform stress analysis of typical glass types for a variety of environmental conditions.
refine and tweak the stress analysis for a particular manufactured glass.
perform rudimentary E1300 calculations of 4 side supported IGUs/or laminates.
use alongside other industry analysis tools, such as Mepla and strand7, to perform capacity calculations.
At present, this package focuses on methods in the Engineering Structural Glass Design Guide by NCSEA (National Council of Structural Engineers Associations) and ASTM E1300.
This package is by no means complete and could be extended in a variety of ways. Contributions and issues are most welcome and can be made on GitHub.
Disclaimer
structuralglass is an open-source engineering project. Although efforts have been made to ensure that the relevant engineering theories have been correctly implemented, it remains the user’s responsibility to confirm and accept the output.
Example Use
import structuralglass.demands as dem
import structuralglass.equiv_thick_models as et
import structuralglass.glass_types as gt
import structuralglass.layers as lay
from structuralglass import Q_
# Glass ply thickness
t1nom = Q_(0.25, "in")
t2nom = Q_(0.25, "in")
t3nom = Q_(0.25, "in")
# Plys
ply1 = lay.GlassPly.from_nominal_thickness(t1nom)
ply2 = lay.GlassPly.from_nominal_thickness(t2nom)
ply3 = lay.GlassPly.from_nominal_thickness(t3nom)
# Interlayer details
t_pvb = Q_(1.52, "mm")
product_name = "PVB NCSEA"
interlayer = lay.Interlayer.from_product_table(t_pvb, product_name)
interlayer.duration = Q_(3, "sec")
interlayer.temperature = Q_(30, "degC")
# Panel force
wind_load = Q_(30, "psf")
# Allowable stress
ft = gt.GlassType.from_abbr("FT")
a_stress = (
ft.prob_breakage_factor(1 / 1000)
* ft.load_duration_factor(Q_(3, "sec"))
* ft.surf_treat_factor("None")
* ft.stress_edge
)
# Plate dimensions
a = Q_(13, "ft")
b = Q_(5, "ft")
# Allowable deflection
defl_max = min(a, b) / 75
# Package specifying the model type
package1 = et.ShearTransferCoefMethod([ply1, interlayer, ply2], min(a, b))
package2 = et.MonolithicMethod([ply3])
buildup = [package1, package2]
# Panel
panel = dem.IGUWindDemands(buildup, wind_load, dim_x=a, dim_y=b)
panel.solve()
# Results
print("-------------Ply values-------------")
print("Ply 1 min allowable thickness:", end=" ")
print(f"{ ply1.t_min.to('in') :.2f~P}", end="\n\n")
print("-------------Interlayer values-------------")
print("Interlayer shear modulus:", end=" ")
print(f"{ interlayer.G.to('MPa') :.2f~P}", end="\n\n")
print("-------------Package values-------------")
print("Eff thick of package 1 for displ:", end=" ")
print(f"{ package1.h_efw.to('in') :.2f~P}")
print("Eff thick of package 2 for stress in ply 3:", end=" ",)
print(f"{ package2.h_efs[ply3].to('in') :.2f~P}", end="\n\n")
print("-------------LSF values of panel-------------")
print(f"Load share of package 1: { panel.LSF[package1] :.3f~P}")
print(f"Load share of package 2: { panel.LSF[package2] :.3f~P}", end="\n\n")
print("-------------Stress and utilizations values of plys-------------")
print(f"Allowable stress: { a_stress.to('ksi') :.2f~P}")
print(f"Stress in ply 1: { panel.stress[ply1].to('ksi') :.2f~P} =>", end=" ")
print(f"{(panel.stress[ply1]/a_stress).to_reduced_units():.2%~P}")
print(f"Stress in ply 2: { panel.stress[ply2].to('ksi') :.2f~P} =>", end=" ")
print(f"{(panel.stress[ply2]/a_stress).to_reduced_units():.2%~P}")
print(f"Stress in ply 3: { panel.stress[ply3].to('ksi') :.2f~P} =>", end=" ")
print(f"{(panel.stress[ply3]/a_stress).to_reduced_units():.2%~P}", end="\n\n")
print("-------------Displacement values of the package-------------")
disp_p1 = panel.deflection[package1]
disp_p2 = panel.deflection[package2]
print(f"Allowable deflection: { defl_max.to('in') :.2f~P}")
print(f"Defl of package 1: { disp_p1.to('in') :.2f~P} =>", end=" ")
print(f"{ abs(disp_p1/defl_max).to_reduced_units() :.2%~P}")
print(f"Defl of package 2: { disp_p2.to('in') :.2f~P} =>", end=" ")
print(f"{ abs(disp_p1/defl_max).to_reduced_units() :.2%~P}")
-------------Ply values-------------
Ply 1 min allowable thickness: 0.22 in
-------------Interlayer values-------------
Interlayer shear modulus: 0.97 MPa
-------------Package values-------------
Eff thick of package 1 for displ: 0.40 in
Eff thick of package 2 for stress in ply 3: 0.22 in
-------------LSF values of panel-------------
Load share of package 1: 0.862
Load share of package 2: 0.138
-------------Stress and utilizations values of plys-------------
Allowable stress: 9.64 ksi
Stress in ply 1: 2.26 ksi => 23.43%
Stress in ply 2: 2.26 ksi => 23.43%
Stress in ply 3: 1.45 ksi => 15.06%
-------------Displacement values of the package-------------
Allowable deflection: 0.80 in
Defl of package 1: -0.43 in => 53.14%
Defl of package 2: -0.43 in => 53.14%