MoorPy unload with rods for cables

-edits to moorpy unload to automatically use rods as connections between line segments
-uses Force vector at each point to set direction of Rod
-initially checks the force vector and sets the A/B rod connections so that they are connecting towards +X (this might not work for every cable configuration)
-points have a cable attribute that must be switched to True to output rods instead of points
-creates generic rod type if any point.Cable == True
-added self.rodTypes = {} to subsystem so that subsystem.unload works

moorpy/point.py

@@ -68,6 +68,8 @@ def __init__(self, mooringSys, num, type, r, m=0, v=0, fExt=np.zeros(3), DOFs=[0
 
  self.attached = [] # ID numbers of any Lines attached to the Point
  self.attachedEndB = [] # specifies which end of the line is attached (1: end B, 0: end A)
+
+ self.cable = False # specifies whether the point should be modeled as a Rod (for dynamic cables) or not
 
  if len(zSpan)==2:
  self.zSpan = np.array(zSpan, dtype=float)

moorpy/subsystem.py

@@ -59,7 +59,7 @@ def __init__(self, mooringSys=None, num=0, depth=0, rho=1025, g=9.81,
  self.pointList = []
  self.lineList = []
  self.lineTypes = {} # dict indexed as a list [0:n-1] corresponding to lineList. Contains *references* to lineType dicts.
- #self.rodTypes = {}
+ self.rodTypes = {}
 
  # some basic subsystem things
  self.rA = np.zeros(3)

moorpy/system.py

@@ -1171,15 +1171,43 @@ def unload(self, fileName, MDversion=2, line_dL=0, rod_dL=0, flag='p', outputLis
 
  # Figure out mooring line attachments (Create a ix2 array of connection points from a list of m points)
  connection_points = np.empty([len(self.lineList),2]) #First column is Anchor Node, second is Fairlead node
+ rod_ends = np.empty([len(self.lineList),2])
  for point_ind,point in enumerate(self.pointList,start = 1): #Loop through all the points
  for (line,line_pos) in zip(point.attached,point.attachedEndB): #Loop through all the lines #s connected to this point
  if line_pos == 0: #If the A side of this line is connected to the point
- connection_points[line -1,0] = point_ind #Save as as an Anchor Node
+ if point.cable == True:
+ connection_points[line -1,0] = -point_ind #Save as as an Anchor Node
+
+ #determine which end of rod to connect to
+ F = point.getForces(lines_only = True, xyz = True)
+ if F[0] > 0:
+ rod_ends[line - 1, 0] = 1
+ else:
+ rod_ends[line - 1, 0] = 0
+ else:
+ connection_points[line -1,0] = point_ind #Save as as an Anchor Node
  #connection_points[line -1,0] = self.pointList.index(point) + 1
  elif line_pos == 1: #If the B side of this line is connected to the point
- connection_points[line -1,1] = point_ind #Save as a Fairlead node
+ if point.cable == True:
+ connection_points[line -1,1] = -point_ind #Save as a Fairlead node
+
+ #determine which end of rod to connect to
+ F = point.getForces(lines_only = True, xyz = True)
+ if F[0] > 0:
+ rod_ends[line - 1, 1] = 0
+ else:
+ rod_ends[line - 1, 1] = 1
+ else:
+ connection_points[line -1,1] = point_ind #Save as a Fairlead node
  #connection_points[line -1,1] = self.pointList.index(point) + 1
 
+ #check if any points have cable = True, this determines if rods are needed
+ cable = False
+ for point in self.pointList:
+ if point.cable == True:
+ cable = True
+ break
+
  #Line Properties
  flag = "p" # "-" 
 
@@ -1227,12 +1255,18 @@ def unload(self, fileName, MDversion=2, line_dL=0, rod_dL=0, flag='p', outputLis
  L.append("TypeName Diam Mass/m Cd Ca CdEnd CaEnd")
  L.append("(name) (m) (kg/m) (-) (-) (-) (-)")
 
+
  for key, rodType in self.rodTypes.items(): 
  di = rodTypeDefaults.copy()
  di.update(rodType)
  L.append("{:<15} {:7.4f} {:8.2f} {:<7.3f} {:<7.3f} {:<7.3f} {:<7.3f}".format(
  key, di['d_vol'], di['m'], di['Cd'], di['Ca'], di['CdEnd'], di['CaEnd']))
 
+ # add arbitrary rod for cable connections if cable is True
+ if cable:
+ L.append("{:<15} {:7.4f} {:8.2f} {:<7.3f} {:<7.3f} {:<7.3f} {:<7.3f}".format(
+ 'connector', 0.2, 0.0 , 0.0, 0.0, 0.0, 0.0))
+
 
  L.append("----------------------- BODIES ------------------------------------------------------")
  L.append("ID Attachment X0 Y0 Z0 r0 p0 y0 Mass CG* I* Volume CdA* Ca*")
@@ -1258,30 +1292,61 @@ def unload(self, fileName, MDversion=2, line_dL=0, rod_dL=0, flag='p', outputLis
  # Rod Properties Table TBD <<<
 
 
+ #add zero length rods for dynamic cables
+ rod_id = 0
+ for point in self.pointList:
+ point_pos = point.r
+ if point.cable == True:
+
+ rod_id = rod_id + 1
+ if point.type == 1: # point is fixed or attached (anch, body, fix)
+ point_type = 'Fixed'
+
+ #Check if the point is attached to body
+ for body in self.bodyList:
+ for attached_Point in body.attachedP:
+ if attached_Point == point.number:
+ point_type = "Body" + str(body.number)
+ point_pos = body.rPointRel[body.attachedP.index(attached_Point)] # get point position in the body reference frame
+
+ elif point.type == 0: # point is coupled externally (con, free)
+ point_type = 'Free'
+
+ elif point.type == -1: # point is free to move (fair, ves)
+ point_type = 'Coupled'
+
+ f = point.getForces(lines_only = True, xyz = True)
+ f_unit = f / np.linalg.norm(f)
+ rA = [point_pos[0] - f_unit[0], point_pos[1] - f_unit[1], point_pos[2] - f_unit[2]]
+ rB = [point_pos[0] + f_unit[0], point_pos[1] + f_unit[1], point_pos[2] + f_unit[2]]
+ L.append("{:<4d} {:9} {:9} {:8.2f} {:8.2f} {:9.2f} {:6.2f} {:6.2f} {:6.2f} {} {}".format(
+ rod_id, 'connector', point_type, rA[0], rA[1], rA[2], rB[0], rB[1], rB[2], 0, '-'))
+
  L.append("---------------------- POINTS -------------------------------------------------------")
  L.append("ID Attachment X Y Z Mass Volume CdA Ca")
  L.append("(#) (-) (m) (m) (m) (kg) (mˆ3) (m^2) (-)")
 
  for point in self.pointList:
- point_pos = point.r # get point position in global reference frame to start with
- if point.type == 1: # point is fixed or attached (anch, body, fix)
- point_type = 'Fixed'
-
- #Check if the point is attached to body
- for body in self.bodyList:
- for attached_Point in body.attachedP:
- if attached_Point == point.number:
- point_type = "Body" + str(body.number)
- point_pos = body.rPointRel[body.attachedP.index(attached_Point)] # get point position in the body reference frame
-
- elif point.type == 0: # point is coupled externally (con, free)
- point_type = 'Free'
+ if point.cable == False:
+ point_pos = point.r # get point position in global reference frame to start with
+ if point.type == 1: # point is fixed or attached (anch, body, fix)
+ point_type = 'Fixed'
 
- elif point.type == -1: # point is free to move (fair, ves)
- point_type = 'Coupled'
-
- L.append("{:<4d} {:9} {:8.2f} {:8.2f} {:8.2f} {:9.2f} {:6.2f} {:6.2f} {:6.2f}".format(
- point.number,point_type, point_pos[0],point_pos[1],point_pos[2], point.m, point.v, point.CdA, point.Ca))
+ #Check if the point is attached to body
+ for body in self.bodyList:
+ for attached_Point in body.attachedP:
+ if attached_Point == point.number:
+ point_type = "Body" + str(body.number)
+ point_pos = body.rPointRel[body.attachedP.index(attached_Point)] # get point position in the body reference frame
+
+ elif point.type == 0: # point is coupled externally (con, free)
+ point_type = 'Free'
+
+ elif point.type == -1: # point is free to move (fair, ves)
+ point_type = 'Coupled'
+
+ L.append("{:<4d} {:9} {:8.2f} {:8.2f} {:8.2f} {:9.2f} {:6.2f} {:6.2f} {:6.2f}".format(
+ point.number,point_type, point_pos[0],point_pos[1],point_pos[2], point.m, point.v, point.CdA, point.Ca))
 
 
  L.append("---------------------- LINES --------------------------------------------------------")
@@ -1290,10 +1355,15 @@ def unload(self, fileName, MDversion=2, line_dL=0, rod_dL=0, flag='p', outputLis
 
  for i,line in enumerate(self.lineList):
  nSegs = int(np.ceil(line.L/line_dL)) if line_dL>0 else line.nNodes-1 # if target dL given, set nSegs based on it instead of line.nNodes
-
- L.append("{:<4d} {:<15} {:^5d} {:^5d} {:8.3f} {:4d} {}".format(
- line.number, line.type['name'], int(connection_points[i,0]), int(connection_points[i,1]), line.L, nSegs, flag))
-
+ if connection_points[i,0] < 0:
+ attach = ['A', 'B']
+ L.append("{:<4d} {:<15} {} {} {:8.3f} {:4d} {}".format(
+ line.number, line.number - 1, 'R'+str(int(-connection_points[i,0]))+attach[int(rod_ends[i,0])], 'R' +str(int(-connection_points[i,1])) +attach[int(rod_ends[i,1])], line.L, nSegs, flag))
+
+ else:
+ L.append("{:<4d} {:<15} {:^5d} {:^5d} {:8.3f} {:4d} {}".format(
+ line.number, line.type['name'], int(connection_points[i,0]), int(connection_points[i,1]), line.L, nSegs, flag))
+
 
  L.append("---------------------- OPTIONS ------------------------------------------------------")