Wire Rope starting properties and parseYAML fix

- System.parseYAML wasn't setting the mass vs. weight correctly for some reason, so I put in a fix for that
- Wire rope properties are now added to MoorProps_default.yaml
- - However, they're still missing cost properties, and drag and added mass properties

moorpy/MoorProps_default.yaml

@@ -73,7 +73,12 @@ lineProps:
  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] 
+ dvol_dnom : 1.18 # volume-equivalent diameter per nominal diameter [-] (assumes 4,875.5 kg/m^3 material density)
+ MBL_d2 : 1022e6 # minimum breaking load per diameter^2 [N/m^2] 
+ EA_d2 : 97.1e9 # stiffness per diameter^2 [N/m^2] 
 
  polyester : # polyester synthetic rope
  mass_d2 : 679 # linear mass density per diameter^2 [kg/m/m^2] 

moorpy/system.py

@@ -887,9 +887,10 @@ def parseYAML(self, data):
  for d in data['line_types']:
  name = d['name']
  dia = float(d['diameter'] )
- w = float(d['mass_density'])*self.g
+ m = float(d['mass_density'])
+ w = (m - np.pi/4*dia**2 *self.rho)*self.g
  EA = float(d['stiffness'] )
- self.lineTypes[name] = dict(name=name, d_vol=dia, w=w, EA=EA)
+ self.lineTypes[name] = dict(name=name, d_vol=dia, m=m, w=w, EA=EA)
 
  addToDict(d, self.lineTypes[name], 'breaking_load' , 'MBL' , default=0)
  addToDict(d, self.lineTypes[name], 'cost' , 'cost', default=0)