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Elastic Link

A nested class within Boundary used to create elastic connections between nodes with various spring properties and link types.

Constructor

Boundary.ElasticLink(i_node, j_node, group = "", id = None, link_type = "GEN", sdx = 0, sdy = 0, sdz = 0, srx = 0, sry = 0, srz = 0, shear = False, dr_y = 0.5, dr_z = 0.5, beta_angle = 0, dir = "Dy", func_id = 1, distance_ratio = 0)

Creates elastic links between two nodes with specified spring properties and behavior.

Parameters

  • i_node: First node ID
  • j_node: Second node ID
  • group (default=""): Boundary group name
  • id (default=None): Manual ID assignment (auto-assigned if None)
  • link_type (default="GEN"): Type of elastic link
  • sdx, sdy, sdz (default=0): Translational spring stiffness in X, Y, Z directions
  • srx, sry, srz (default=0): Rotational spring stiffness about X, Y, Z axes
  • shear (default=False): Consider shear effects
  • dr_y, dr_z (default=0.5): Distance ratios for Y and Z directions
  • beta_angle (default=0): Rotation angle in degrees
  • dir (default="Dy"): Direction for specialized link types
  • func_id (default=1): Function ID for specialized link types
  • distance_ratio (default=0): Distance ratio for specialized link types
  • "GEN": General elastic link with full stiffness matrix
  • "RIGID": Rigid connection (infinite stiffness)
  • "TENS": Tension-only link (works only in tension)
  • "COMP": Compression-only link (works only in compression)
  • "MULTI LINEAR": Multi-linear behavior with function definition
  • "SADDLE": Saddle-type connection
  • "RAIL INTERACT": Rail track interaction link

Class Attributes

Boundary.ElasticLink.links -> List of all elastic link instances.

Object Attributes

  • I_NODE (int): The first node ID of the link.
  • J_NODE (int): The second node ID of the link.
  • GROUP_NAME (str): The name of the boundary group.
  • LINK_TYPE (str): The type of elastic link (e.g., "GEN", "RIGID", "TENS").
  • ANGLE (float): The beta angle (rotation) in degrees.
  • SDx (float): Spring stiffness in the X direction.
  • SDy (float): Spring stiffness in the Y direction.
  • SDz (float): Spring stiffness in the Z direction.
  • SRx (float): Rotational stiffness about the X axis.
  • SRy (float): Rotational stiffness about the Y axis.
  • SRz (float): Rotational stiffness about the Z axis.
  • bSHEAR (bool): Flag to consider shear effects.
  • DR_Y (float): Distance ratio for shear effects in the Y direction.
  • DR_Z (float): Distance ratio for shear effects in the Z direction.
  • Direction (str): Direction for "MULTI LINEAR" or "RAIL INTERACT" links (e.g., "Dy").
  • Function_ID (int): Function ID for "MULTI LINEAR" or "RAIL INTERACT" links.
  • Distance_ratio (float): Distance ratio for "MULTI LINEAR" or "RAIL INTERACT" links.
  • ID (int): The ID of the elastic link.

Methods

json

Returns JSON representation of all elastic links.

link1 = Boundary.ElasticLink(1, 2, "Group1", 1, "GEN", 1000, 1000, 1000)
print(Boundary.ElasticLink.json())

create

Sends elastic link data to Civil NX.

Boundary.ElasticLink.create()

get

Fetches elastic link data from Civil NX.

print(Boundary.ElasticLink.get())

sync

Synchronizes elastic links from Civil NX to Python.

Boundary.ElasticLink.sync()

delete

Deletes all elastic links from both Python and Civil NX.

Boundary.ElasticLink.delete()

Examples

#General Elastic Link Example

#Create Beam and Node
for j in range(2):
    for i in range(2):
        Node(i*10,0,-1*j)
        Node.create()
Element.Beam(1,2)
Element.create()

#Create General Elastic Link    
Boundary.ElasticLink(1, 3, "", 1, "GEN", 1000, 1000, 1000, 100, 100, 100)
Boundary.ElasticLink.create()

#Rigid Link Example

#Create Beam and Node
for j in range(2):
    for i in range(2):
        Node(i*10,0,-1*j)
        Node.create()
Element.Beam(1,2)
Element.create()

#Create Rigid Link    
Boundary.ElasticLink(2, 4, "", 1, "RIGID")
Boundary.ElasticLink.create()

#Tension-Only & Compression-Only Link Example

#Create Beam and Node
for j in range(2):
    for i in range(2):
        Node(i*10,0,-1*j)
        Node.create()
Element.Beam(1,2)
Element.create()

#Tension-Onl & Compression-Only Link    
Boundary.ElasticLink(1, 3, "", 1, "TENS",500)
Boundary.ElasticLink(2, 4, "", 2, "COMP",600)
Boundary.ElasticLink.create()

#Saddle type Link Example

#Create Beam and Node
for j in range(2):
    for i in range(2):
        Node(i*10,0,-1*j)
        Node.create()
Element.Beam(1,2)
Element.create()


#Create Saddle type Link    
Boundary.ElasticLink(1, 3, "", 1, "SADDLE")
Boundary.ElasticLink.create()

#Multi-linear link Example

#Create Beam and Node
for j in range(2):
    for i in range(2):
        Node(i*10,0,-1*j)
        Node.create()
Element.Beam(1,2)
Element.create()


# Multi-linear link
Boundary.ElasticLink(1, 3, "", 1, "MULTI LINEAR", dir="Dy", func_id=1)
Boundary.ElasticLink.create()

#Note: Before running this code, the Force-Deformation function must be created in Civil NX to avoid any errors.

# Rail track interaction link Example

#Create Beam and Node
for j in range(2):
    for i in range(2):
        Node(i*10,0,-1*j)
        Node.create()
Element.Beam(1,2)
Element.create()


# Rail track interaction link
Boundary.ElasticLink(2, 4, "", 1, "RAIL INTERACT", dir="Dy", func_id=1)
Boundary.ElasticLink.create()

#Note: Before running this code, the Rail Interaction function must be created in Civil NX to avoid any errors.