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add R3 studlink/studless chain properties to database #71

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add R3 studlink/studless chain properties to database #71

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1415cf2
add R3 sudlink and stuless lineProps, resolves #69
Oct 15, 2026
d21d65f
fix chain cost
Oct 15, 2026
605d200
add notes for R3 chains properties
mutricyl Oct 16, 2026
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35 changes: 30 additions & 5 deletions moorpy/library/MoorProps_newCosts.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -48,10 +48,11 @@
# Chain Notes
# - The MBLs between studless and studlink chains are the same, for every grade
# - The masses between different grades of chain are the same (for now...different grades might correspond to different material densities)
# - If the user needs a different grade of chain, they will have to add another section and include those properties here. This default file only considers R4 chain
# - If the user needs a different grade of chain, they will have to add another section and include those properties here. This file only considers R3 and R4 chain
# - This default yaml uses R4 studless chain as the default style of chain
# - The chain MBL uses a cubic function, so be aware if you are researching theoretical chains with diameters greater than about 360mm, as the MBL will then decrease
# - Chain EA values not provided in manufacturer catalogs, so the below coefficients are taken from DNV-OS-E301 2013
# - Chain EA values not provided in manufacturer catalogs, so the below coefficients are taken from DNV-OS-E301 2013 section 2.1.8
# - R3 Chain MBL is derived from Anchor Marine Houston catalogue pages 52&53 (https://anchormarinehouston.com/wp-content/uploads/2023/08/Anchor-Marine-Catalog.pdf)

# Note: costs combine all provided coefficients. If a coefficient is not provided it is assumed zero. All provided values will be used according to:
# cost per meter = 'cost_0' + 'cost_d' * d + 'cost_d2' * d**2 + 'cost_d3' * d**3 + 'cost_mass' * mass per meter + 'cost_EA' * EA + 'cost_MBL' * MBL
Expand Down Expand Up @@ -87,10 +88,34 @@ lineProps:
Ca : 1.0 # added mass coefficient based on Bureau Veritas 493-NR_2021-07
Ca_ax : 0.5 # axial added mass coefficient based on Bureau Veritas 493-NR_2021-07

chainR3 : # R3 grade chain, studless and studlink. Not included in OMAE2025-156384 in interest of brevity
mass_d2 : 21e3 # linear mass density per diameter^2 [kg/m/m^2] - avg R4 studlink and R4 studless
chainR3 : # R3 grade chain, studless
mass_d2 : 20.0e3 # linear mass density per diameter^2 [kg/m/m^2]
EA_d3 : -6.283e07 # stiffness per diameter^3 [N/m^3]

@RyanDavies19 RyanDavies19 Oct 15, 2026 •
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Is there a reason that this differs from R4 for studless while it is the same as R4 for stud link?

@mutricyl mutricyl Oct 16, 2026

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mass_d2 is 20.0e3 for studless and 21.9e3 for studlink and is the same for R3 and R4

@RyanDavies19 RyanDavies19 Oct 16, 2026

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Yep, sorry I was referring to the EA values. I left a commend for @shousner below to address it.

EA_d2 : 84.82e9 # stiffness per diameter^2 [N/m^2]
MBL_d3 : -1.784e09 # minimum breaking load per diameter^3 [N/m^3]

@RyanDavies19 RyanDavies19 Oct 15, 2026

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Am I correct in reading that other than the EA difference flagged above, the only difference between R3 and R4 is the the MBL curves (which you pulled from the Anchor Marine catalogue)?

@mutricyl mutricyl Oct 16, 2026

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Correct, steel grade only changes MBL and EA

@RyanDavies19 RyanDavies19 Oct 16, 2026

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@shousner I'll let you decide on EA values, thats more your domain. In general though I agree that it should follow what is in the standards.

MBL_d2 : 9.812e08 # minimum breaking load per diameter^2 [N/m^2]
MBL_d : 1.033e03 # minimum breaking load per diameter [N/m]
dvol_dnom : 1.80 # volume-equivalent diameter per nominal diameter [-] (assumes 7,850 kg/m^3 material density)
cost_d : -2.34e2 # cost per meter per diameter [2024$/m^2]
cost_d2 : 5.95e4 # cost per meter per diameter^2 [2024$/m^3]
Cd : 1.333 # drag coefficient based on DNV-OS-E301 adjusted for use with volumetric diameter
Cd_ax : 0.639 # axial drag coefficient based on DNV-OS-E301 adjusted for use with volumetric diameter
Ca : 1.0 # added mass coefficient based on Bureau Veritas 493-NR_2021-07
Ca_ax : 0.5 # axial added mass coefficient based on Bureau Veritas 493-NR_2021-07

chainR3_studlink : # R3 grade chain, studllink.
mass_d2 : 21.9e3 # linear mass density per diameter^2 [kg/m/m^2] (same density as R4)
EA_d2 : 88.0e9 # stiffness per diameter^2 [N/m^2]
MBL_d3 : -1.784e09 # minimum breaking load per diameter^3 [N/m^3]
MBL_d2 : 9.812e08 # minimum breaking load per diameter^2 [N/m^2]
MBL_d : 1.985e03 # minimum breaking load per diameter [N/m]
dvol_dnom : 1.89 # volume-equivalent diameter per nominal diameter [-] (assumes 7,850 kg/m^3 material density)
cost_d : -2.34e2 # cost per meter per diameter [2024$/m^2]
cost_d2 : 5.95e4 # cost per meter per diameter^2 [2024$/m^3]
Cd : 1.376 # drag coefficient based on DNV-OS-E301 adjusted for use with volumetric diameter
Cd_ax : 0.741 # axial drag coefficient based on DNV-OS-E301 adjusted for use with volumetric diameter
Ca : 1.0 # added mass coefficient based on Bureau Veritas 493-NR_2021-07
Ca_ax : 0.5 # axial added mass coefficient based on Bureau Veritas 493-NR_2021-07

wire : # wire rope
mass_d2 : 5293 # linear mass density per diameter^2 [kg/m/m^2]
Expand Down Expand Up @@ -140,4 +165,4 @@ lineProps:
Ca : 1.1 # added mass coefficient based on Bureau Veritas 493-NR_2021-07
Ca_ax : 0.15 # axial added mass coefficient based on Bureau Veritas 493-NR_2021-07
cost_d : -2.27e3 # cost per meter per diameter [2024$/m^2]
cost_d2 : 1.10e5 # cost per meter per diameter^2 [2024$/m^3]
cost_d2 : 1.10e5 # cost per meter per diameter^2 [2024$/m^3]