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Point Spring

A nested class within Boundary used to create point springs at nodes with various spring properties and behaviors.

Constructor

Boundary.PointSpring(node, spring_type = "LINEAR", group = "", id = None, stiffness = None, fixed_option = None, damping = None, direction = "Dx+", normal_vector = None, function_id = 1)

Creates point springs at specified nodes with defined spring properties and behavior types.

Parameters

  • node: Node ID where spring is applied
  • spring_type (default="LINEAR"): Type of spring behavior
  • group (default=""): Boundary group name
  • id (default=None): Manual ID assignment (auto-assigned if None)
  • stiffness (default=None): Spring stiffness values or single value
  • fixed_option (default=None): Fixed option array for LINEAR type
  • damping (default=None): Damping values (enables damping if provided)
  • direction (default="Dx+"): Direction string for spring action
  • normal_vector (default=None): Normal vector [x, y, z] when direction is "Vector"
  • function_id (default=1): Function ID for MULTI type springs

Spring Types

  • "LINEAR": Linear spring with full 6-DOF stiffness matrix
  • "COMP": Compression-only spring
  • "TENS": Tension-only spring
  • "MULTI": Multi-linear behavior with function definition

Direction Options

  • "Dx+", "Dx-": Positive/Negative X direction
  • "Dy+", "Dy-": Positive/Negative Y direction
  • "Dz+", "Dz-": Positive/Negative Z direction
  • "Vector": Custom vector direction (requires normal_vector)

Class Attributes

Boundary.PointSpring.springs -> List of all point spring instances.

Object Attributes

  • NODE (int): The node ID where the spring is applied.
  • TYPE (str): The type of spring (e.g., "LINEAR", "COMP", "TENS", "MULTI").
  • GROUP_NAME (str): The name of the boundary group.
  • DIR (int): Direction integer (converted from direction string).
  • ID (int): The ID of the point spring.

For LINEAR type:

  • SDR (list): Spring stiffness values [SDx, SDy, SDz, SRx, SRy, SRz].
  • F_S (list): Fixed option array [Boolean, 6].
  • DAMPING (bool): Flag indicating if damping is enabled.
  • Cr (list): Damping values [Cx, Cy, Cz, CRx, CRy, CRz].

For COMP/TENS types:

  • STIFF (float): Spring stiffness value.
  • DV (list): Normal vector [x, y, z].

For MULTI type:

  • DV (list): Normal vector [x, y, z].
  • FUNCTION (int): Function ID for multi-linear behavior.

Methods

json

Returns JSON representation of all point springs.

spring1 = Boundary.PointSpring(1, "LINEAR", "", stiffness=[1000, 1000, 1000, 100, 100, 100])
print(Boundary.PointSpring.json())

create

Sends point spring data to Civil NX.

Boundary.PointSpring.create()

get

Fetches point spring data from Civil NX.

print(Boundary.PointSpring.get())

sync

Synchronizes point springs from Civil NX to Python.

Boundary.PointSpring.sync()

delete

Deletes all point springs from both Python and Civil NX.

Boundary.PointSpring.delete()

Examples

Linear Spring

# Linear Spring Example

# Create Node
Node(0, 0, 0)
Node.create()

# Create Linear Point Spring with full stiffness matrix
Boundary.PointSpring(1, "LINEAR", "", stiffness=[1000, 1000, 1000, 100, 100, 100])
Boundary.PointSpring.create()

Linear Spring with Damping

# Linear Spring with Damping Example

# Create Node
Node(0, 0, 0)
Node.create()

# Create Linear Point Spring with damping
Boundary.PointSpring(1, "LINEAR", "", 
                    stiffness=[1000, 1000, 1000, 100, 100, 100],
                    damping=[10, 10, 10, 1, 1, 1])
Boundary.PointSpring.create()

Compression-Only Spring

# Compression-Only Spring Example

# Create Node
Node(0, 0, 0)
Node.create()

# Create Compression-Only Spring in Z+ direction
Boundary.PointSpring(1, "COMP", "Group2", stiffness=5000, direction="Dz+")
Group.create()
Boundary.PointSpring.create()

Tension-Only Spring

# Tension-Only Spring Example

# Create Node
Node(0, 0, 0)
Node.create()

# Create Tension-Only Spring in Y- direction
Boundary.PointSpring(1, "TENS", "", stiffness=3000, direction="Dy-")
Boundary.PointSpring.create()

Spring with Vector Direction

# Spring with Vector Direction Example

# Create Node
Node(0, 0, 0)
Node.create()

# Create Tension-Only Spring with custom vector direction
Boundary.PointSpring(1, "TENS", "", 
                    stiffness=3000, 
                    direction="Vector", 
                    normal_vector=[0, -1, -1])
Boundary.PointSpring.create()

Multi-Linear Spring

# Multi-Linear Spring Example

# Create Node
Node(0, 0, 0)
Node.create()

# Create Multi-Linear Spring (requires function definition)
Boundary.PointSpring(1, "MULTI", "", 
                    direction="Dz+", 
                    function_id=1)
Boundary.PointSpring.create()

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