Dwarf Fortress Bug Tracker - Dwarf Fortress
View Issue Details
IDProjectCategoryView StatusDate SubmittedLast Update
0009976Dwarf FortressMaterial Propertiespublic2016-08-23 16:492017-07-30 15:48
Reporterchaosvolt 
Assigned To 
PrioritynormalSeverityminorReproducibilityhave not tried
StatusnewResolutionopen 
PlatformOSOS Version
Product Version 
Target VersionFixed in Version 
Summary0009976: Possibly incorrect value for bone (and maybe stone) shear strength
DescriptionAttempts to look up bone's shear values has led to my finding commonly-cited numbers to be different from what the game uses.

In particular, the raws cite referencing wikipedia, and their article for bone ( https://en.wikipedia.org/wiki/Bone [^] ) states a tensile strength that the raw is in the right range of (104-121 MPa versus 105000 KPa), but the raws use the same shear strength for the shear value, with said page cites two sources as 51.6 MPa (or in DF terms, 51600). Other cursory searches have shown that number come up elsewhere.

I'm not sure what the real-world shear FRACTURE of bone is though.

I then started to look up the shear value of marble, which the raws state the stone template based some values off of. Getting that value is proving to be harder, and I don't know where Toady got the value from.
Steps To Reproduce
Additional InformationChanging this would make combatants rather more fragile, and might have variable effects on modding (especially those focused on adventure-mode crafting).

Stone and obsidian currently would still cut worse than this altered bone value, but I also have no idea where these values were obtained. Plus, currently DF logic has sandstone cutting as well as chert.
Tagsbone, material, material template, research, shear strength, stone
Relationships
Attached Files
Issue History
Date ModifiedUsernameFieldChange
2016-08-23 16:49chaosvoltNew Issue
2016-08-27 10:26chaosvoltTag Attached: bone
2016-08-27 10:26chaosvoltTag Attached: material
2016-08-27 10:26chaosvoltTag Attached: material template
2016-08-27 10:26chaosvoltTag Attached: research
2016-08-27 10:26chaosvoltTag Attached: shear strength
2016-08-27 10:26chaosvoltTag Attached: stone
2016-08-28 11:03chaosvoltNote Added: 0035815
2016-08-28 11:05chaosvoltNote Edited: 0035815bug_revision_view_page.php?bugnote_id=0035815#r14443
2017-07-30 15:48chaosvoltNote Added: 0036683

Notes
(0035815)
chaosvolt   
2016-08-28 11:03   
(edited on: 2016-08-28 11:05)
Another problem with fixing this is that the armor damage system is very poorly balanced. Already mundane wildlife bites will tear through bone armor even if it's been BUFFED to exceed the strength of copper, nerfing would fuck that up even worse. ._.
(0036683)
chaosvolt   
2017-07-30 15:48   
Update. Found one possibly useful source for marble's shear strength. Values for marble vary, including 4964.23, 11031.61, even 16547.42 kpa

So that at least is in the expected range.

Source: http://nceg.uop.edu.pk/GeologicalBulletin/Vol-26-1993/Vol-26-1993-Paper11.pdf [^]