week-11 Joint creation and Demonstration
AIM OF THE PROJECT
To demonstrate spherical, revolute, cylindrical, and translational joints between two rigid bodies and two deformable bodies.
THEORY OF JOINTS
1) Spherical Joint: It is the type of joint which is used for allowing free rotation in two planes at the same time preventing in any direction, including rotation in those planes
The relative motion of the rigid bodies is constrained so that nodes which are initially coincident remain coincident. In the above figure the socket’s node is not interior to the socket—LS-DYNA does not require that a rigid body’s nodes be interior to the body.
(a) Creation of joints between two rigid bodies
Step 1: Create two spherical shell bodies with different diameter using the option Mesh > Shape mesher > Spherical shell. Delete the upper half portion of the outer shell body using Element edit > delete.
Step 2: Assign the material properties for the given shell bodies using MAT_RIGID_020
Step 3: Assign the section properties for the shell elements using the keyword *SECTION_SHELL. The value of thickness is given as 1 mm.
Step 4: Assign the material properties and section properties to the part using *PART
Step 5: A pair of nodes is created using the option Element tools > Node editing > Create. The node 305 is constrained to part 1 and node 306 is constrained to part 2 using *CONSTRAINED_EXTRA_NODES
Step 6: The spherical joint is created using *CONSTRAINED_JOINT_SPHERICAL card with node 305 for N1 and with node 306 for N2
Step 7: Assign the initial velocity for the rigid body using *INITIAL_VELOCITY_RIGID_BODY. The value is loaded as 20 mm/ms for VXR, VYR, VZR
Step 8: Defining control cards
*CONTROL_TERMINATION: The end time of the simulation is specified as 1ms
*CONTROL_TIMESTEP: DTINIT is specified as 0.01 and TSSFAC as 0.9
Step 9: Defining the cards for database
*DATABASE_BINARY_D3PLOT: Time interval between the outputs is given as 0.01 ms
(b) Creation of joints between two deformable bodies
Step 1: The same steps should be followed to create a joint between two deformable bodies, as how we did for rigid bodies
- *MAT_ELASTIC card is used instead of *MAT_RIGID with the same material properties
- CONSTRAINED NODAL RIGID BODY is used to constrain the nodes to the necessary part
- *INITIAL_VELOCITY card is used instead of *INITIAL_VELOCITY_ RIGID_BODY
Step 2: Constrained nodal Rigid Body is used to constrain the nodes to the necessary part. Node 1(305) and Node 2(306) are loaded into *CONSTRAINT_JOINT_SPHERICAL
Step 3: Assign the initial velocity as 20 mm/ms to the moving part in VXR, VYR and VZR
Step 4: Defining control cards
*CONTROL_TERMINATION: The end time of the simulation is specified as 1ms
*CONTROL_TIMESTEP: DTINIT is specified as 0.01 and TSSFAC as 0.9
Step 5: Defining the cards for database
*DATABASE_BINARY_D3PLOT: Time interval between the outputs is given as 0.01 ms
OUTPUT FOR RIGID BODY AND DEFORMABLE BODY
2)Revolute Joint: It is the type of joint which have 1 DOF kinematic pair used frequently in mechanisms and machines. The joint constraints the motion of two bodies to pure rotation along a common axis
Nodes 1 and 2 are coincident; nodes 3 and 4 are coincident. Nodes 1 and 3 belong to rigid body A; nodes 2 and 4 belong to rigid body B. The relative motion of the two rigid bodies is restricted to rotations about the axis formed by the two pairs of coincident nodes. This axis is labeled the “centerline.”
(a) Creation of joints between two rigid bodies
Step 1: Create two spherical shell bodies with different diameter using the option Mesh > Shape mesher > 4N shell. Make sure that the elements of two shell bodies are in the same line of action.
Step 2: Assign the material properties for the given shell bodies using MAT_RIGID_020
Step 3: Assign the section properties for the shell elements using the keyword *SECTION_SHELL. The value of thickness is given as 1 mm.
Step 4: Assign the material properties and section properties to the part using *PART
Step 5: Two pair of nodes are created using Element tools > Node editing > Create i.e. Node 101-102 and Node 103-104. The nodes 101 and 103 is constrained to part 1 and the nodes 102 and 104 is constrained to part 2 using *CONSTRAINED_EXTRA_NODES
Step 6: The revoulte joint is created using *CONSTRAINED_JOINT_REVOLUTE card with nodes N1 and N3 for part 1 and N2 and N4 for part 2
Step 7: Boundary SPC set with all DOF set to 1
Step 8: Boundary Prescribed Motion
Step 9: Defining control cards
*CONTROL_TERMINATION: The end time of the simulation is specified as 1ms
*CONTROL_TIMESTEP: DTINIT is specified as 0.01 and TSSFAC as 0.9. It is defined using time step curve as shown above
Step 10: Defining the cards for database
*DATABASE_BINARY_D3PLOT: Time interval between the outputs is given as 0.01 ms
(b) Creation of joints between two deformable bodies
Step 1: The same steps should be followed to create a joint between two deformable bodies, as how we did for rigid bodies
- *MAT_ELASTIC card is used instead of *MAT_RIGID with the same material properties
- CONSTRAINED NODAL RIGID BODY is used to constrain the nodes to the necessary part
- *INITIAL_VELOCITY card is used instead of *INITIAL_VELOCITY_ RIGID_BODY
Step 2: Two pair of nodes are created using Element tools > Node editing > Create i.e. Node 101-102 and Node 103-104. The nodes 101 and 103 is constrained to part 1 and the nodes 102 and 104 is constrained to part 2 using *CONSTRAINED_EXTRA_NODES
The revolute joint is constrained using *OCNSTRAINED_JOINT_REVOLUTE card with nodes N1 and N3 of part 1 and nodes N2 and N4 of part 2
The nodes of the part 1 is constrained in all degrees of freedom using boundary SPC set and Boundary Prescribed Motion is assigned to node 173
Step 3: Defining control cards
*CONTROL_TERMINATION: The end time of the simulation is specified as 1ms
*CONTROL_TIMESTEP: DTINIT is specified as 0.01 and TSSFAC as 0.9
Step 4: Defining the cards for database
*DATABASE_BINARY_D3PLOT: Time interval between the outputs is given as 0.01 ms
OUTPUT FOR RIGID BODY AND DEFORMABLE BODY
3)Cylindrical Joint: It is a type of joint which have 2 DOF kinematic pair used in mechanisms. It provides single axis sliding function as well as a single axis rotation, providing a way for two rigid bodies to translate and rotate freely.
This joint is derived from the rotational joint by relaxing the constraints along the centerline. This joint admits relative rotation and translation along the centerline.
(a) Creation of joints between two rigid bodies
Step 1: Create two spherical shell bodies with different diameter using the option Mesh > Shape mesher > Cylindrical shell. Make sure that the elements of two shell bodies are in the same line of action.
Step 2: Assign the material properties for the given shell bodies using MAT_RIGID_020
Step 3: Assign the section properties for the shell elements using the keyword *SECTION_SHELL. The value of thickness is given as 1 mm.
Step 4: Assign the material properties and section properties to the part using *PART
Step 5: Two pair of nodes are created using Element tools > Node editing > Create i.e. 321, 322, 323 and 324. The nodes 321 and 323 are constrained to part 1 and the nodes 322 and 324 are constrained to part 2 using *CONSTRAINED_EXTRA_NODES_SET. Node sets should be linked in this card.
Nodes 301, 302, 303 and 304 are loaded into *CONSTRAINED_JOINT_CYLINDRICAL
Step 6: An initial velocity of 10 mm/ms is applied to part 1 in X-direction.
Step 7: Defining control cards
*CONTROL_TERMINATION: The end time of the simulation is specified as 1ms
*CONTROL_TIMESTEP: DTINIT is specified as 0.01 and TSSFAC as 0.9
Step 8: Defining the cards for database
*DATABASE_BINARY_D3PLOT: Time interval between the outputs is given as 0.01 ms
(b) Creation of joints between two deformable bodies
Step 1: The same steps should be followed to create a joint between two deformable bodies, as how we did for rigid bodies
- *MAT_ELASTIC card is used instead of *MAT_RIGID with the same material properties
- CONSTRAINED NODAL RIGID BODY is used to constrain the nodes to the necessary part
- *INITIAL_VELOCITY card is used instead of *INITIAL_VELOCITY_ RIGID_BODY
Step 2: Two pair of nodes are created using Element tools > Node editing > Create i.e. 321, 322, 323 and 324. The nodes 321 and 323 are constrained to part 1 and the nodes 322 and 324 are constrained to part 2 using *CONSTRAINED_NODAL_RIGID_BODY.
Step 3: The initial velocity of 10 mm/ms is applied to part 1 in X-Direction
Step 4: Defining control cards
*CONTROL_TERMINATION: The end time of the simulation is specified as 1ms
*CONTROL_TIMESTEP: DTINIT is specified as 0.01 and TSSFAC as 0.9
Step 5: Defining the cards for database
*DATABASE_BINARY_D3PLOT: Time interval between the outputs is given as 0.01 ms
OUTPUT FOR RIGID BODY AND DEFORMABLE BODY
4)Translational Joint: This type of joint provides a linear sliding movement between two bodies. This is a cylindrical joint with a third pair of off-centerline nodes which restrict rotation. Aside from translation along the centerline, the two rigid bodies are stuck together
(a) Creation of joints between two rigid bodies
Step 1: Create two spherical shell bodies with different diameter using the option Mesh > Shape mesher > Box shell. Make sure that the elements of two shell bodies are in the same line of action.
Step 2: Assign the material properties for the given shell bodies using MAT_RIGID_020
Step 3: Assign the section properties for the shell elements using the keyword *SECTION_SHELL. The value of thickness is given as 1 mm.
Step 4: Assign the material properties and section properties to the part using *PART
Step 5: Two pair of nodes are created using Element tools > Node editing > Create i.e. 1001, 1002, 1003, 1004, 1005 and 1006. Two pairs of nodes are created 1001-1002 and 1003-1004 which is coincident and collinear. The third pair 1005-1006 is coincident and slightly away from the axis of other two pairs. The nodes 1001, 1003, 1005 are constrained to part 1 and the nodes 1002, 1004, 1006 are constrained to part 2 using *CONSTRAINED_EXTRA_NODES card
Nodes 1001, 1002, 1003, 1004, 1005 and 1006 are loaded into *CONSTRAINED_JOINT_CYLINDRICAL
Step 6: An initial velocity of 10 mm/ms is applied to part 1 in X-direction.
Step 7: Defining control cards
*CONTROL_TERMINATION: The end time of the simulation is specified as 1ms
*CONTROL_TIMESTEP: DTINIT is specified as 0.01 and TSSFAC as 0.9
Step 8: Defining the cards for database
*DATABASE_BINARY_D3PLOT: Time interval between the outputs is given as 0.01 ms
(b) Creation of joints between two deformable bodies
Step 1: The same steps should be followed to create a joint between two deformable bodies, as how we did for rigid bodies
- *MAT_ELASTIC card is used instead of *MAT_RIGID with the same material properties
- CONSTRAINED NODAL RIGID BODY is used to constrain the nodes to the necessary part
- *INITIAL_VELOCITY card is used instead of *INITIAL_VELOCITY_ RIGID_BODY
Step 2: Two pair of nodes are created using Element tools > Node editing > Create i.e. 1001, 1002, 1003, 1004, 1005 and 1006. Two pairs of nodes are created 1001-1002 and 1003-1004 which is coincident and collinear. The third pair 1005-1006 is coincident and slightly away from the axis of other two pairs. The nodes 1001, 1003, 1005 are constrained to part 1 and the nodes 1002, 1004, 1006 are constrained to part 2 using *CONSTRAINED_EXTRA_NODES card
Step 3: The initial velocity of 10 mm/ms is applied to part 1 in X-Direction
Step 4: Defining control cards
*CONTROL_TERMINATION: The end time of the simulation is specified as 1ms
*CONTROL_TIMESTEP: DTINIT is specified as 0.01 and TSSFAC as 0.9
Step 5: Defining the cards for database
*DATABASE_BINARY_D3PLOT: Time interval between the outputs is given as 0.01 ms
OUTPUT FOR RIGID BODY AND DEFORMABLE BODY
CONCLUSION
- The demonstration for spherical joints, revolute joints, cylindrical joints and translational joints betwen two rigid bodies and with two deformable bodies using *CONSTRAINED_JOINT keyword is done successfully
- CONSTRAINED EXTRA NODES and CONSTRAINED NODAL RIGID BODY have been used to create the joint for rigid and deformable bodies