0000639: Some impact elasticity values are clearly wrong

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0000639

Dwarf Fortress

Geology

public

2010-04-06 10:16

2010-07-06 03:04

Reporter

Squirrelloid

Assigned To

Toady One

Priority

low

Severity

minor

Reproducibility

always

Status

resolved

Resolution

fixed

Platform

OS Version

Product Version

0.31.01

Target Version

Fixed in Version

0.31.09

Summary

0000639: Some impact elasticity values are clearly wrong

Description

Impact Elasticity for some metals in DF:
Gold 600
Iron 635
Steel 675
Silver 1080
Bronze 600

I'm assuming that high elasticity => deforms more under a given stress, as per real world definition (Strain = E * stress).

While I can't find impact elasticity for real world data, Young's Modulus (inverse tensile elasticity) of gold and silver are virtually identical. Given their similar behavior under many other circumstances based on their periodic table placement and properties, I would assume this holds true for all types of elasticity.

Its certainly the case that gold should not be stiffer than iron and steel.

In fact, it should probably be steel < iron << gold ~= silver, which means one of iron or steel is also wrong. My best guess is that steel should be stiffer than bronze as well, and so steel should have an impact elasticity <600.

(I've mostly looked at weapon-capable metals and impact elasticity, so there may be other inappropriate values)

Steps To Reproduce

Its an incorrect data entry in the raws

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Notes
(0001513) Footkerchief (manager) 2010-04-06 10:25	Please direct all discussion to http://www.bay12games.com/forum/index.php?topic=53072.0 [^]

(0009674) Toady One (administrator) 2010-07-06 03:04	DF's elasticity should be called "STRAIN_AT_YIELD", I think. I'm not sure what permutations it went through to arrive at its current name, but at some point it didn't get a good name. In any case, they are all just the yield divided by a modulus (young's, bulk, etc. depending on case), and I think the last digit is dropped or something. I'm not sure if Young's modulus etc. even applies at yield, but that's what it is doing.

Issue History
Date Modified	Username	Field	Change
2010-04-06 10:16	Squirrelloid	New Issue
2010-04-06 10:25	Footkerchief	Note Added: 0001513
2010-07-06 03:04	Toady One	Note Added: 0009674
2010-07-06 03:04	Toady One	Status	new => resolved
2010-07-06 03:04	Toady One	Fixed in Version	=> 0.31.09
2010-07-06 03:04	Toady One	Resolution	open => fixed
2010-07-06 03:04	Toady One	Assigned To	=> Toady One