week-11 Joint creation and Demonstration

OBJECTIVE :

1. Creating the Revolute joint between two plates.

2. Creating the Cylindrical joint between two concentric cylinders.

3. Creating the Spherical joint between two concentric spheres.

4.Creating the Translational joints between co-axial boxes.

 

CASE SET UP :

CASE 1 : CREATING THE REVOLUTE JOINT 

1. Creating the coincident Nodes between the plates

         Two pair of coincident nodes along the axis of revolution are to be created such that the one node of each pair belongs to the other plate.i.e,

if two nodes with ID's say 159 and 161 are coincident and another pair of coincident nodes with Node ID's say 160 and 162 , then the nodes 159 and 160 belong to plate-1 and the nodes 161 and 162 are belong to plate-2. The nodes are created along the axis of revolution between the plates using the Node edit tool in the Mesh Tools option.

Fig 1 Creation of two pairs of coincident Nodes along the axis of revolution

2. Creating the CNRB'S(Constrained Nodal Rigid Bodies)

        Each different node of the Coincident pairs is used for creating CNRB with different plate. Suppose, the nodes 155 and 156 are coincident then the using the Node 155, the CNRB is constructed for the Plate-1 and using the node 156 the CNRB is constructed  for the Plate-2. Hence, a total of four CNRB are constructed using the create entity tool bar. One of the coincident node becomes the parent node where as the other four nodes are chosen to be as the child nodes. 

Fig 2 Creating the Constrained nodal rigid bodies

3. Creating the Revolute joints

        The revolute joints are created by using the keyword *Constrained_Joint_revolute. The Parent nodes of the CNRB are entered in the card in order to create the revolute joint. N1 and N3 are the parent nodes connecting the Plate-1 where as the Nodes N2 and N3 are the parent nodes connecting the Plate-2.

Fig 3 Creating the revolute joint

         The coicident node pairs thus form the axis of revolution for the revolute joint.

Fig 4 Revolute joint between the plates

4. Applying the boundary conditions

     i. Applying the SPC  to the Plate-1 nodeset 

       All the nodes on the Plate-1 are constrained for all degrees of freedom using the keyword *boundary_SPC_Set .

Fig 5 Applying the SPC to all nodes of the Plate-1

        ii. Applying the Prescribed motion set to the nodes in plate-2

                 Using the keyword * Boundary_Prescribed_motion_set, the translational displacement is provided to the z-direction to the free edge of the plate-2 which is in the x-direction so that the Plate-2 revolves about the revolute joint. The curve that describes the displacement motion is also defined and assigned to the keyword.

Fig 6 Applying the Prescribed motion to the plate

5.Creating the Material card

         The Material card is created for the plates in the keyword Material_001_Elastic and all the properties of the material are assigned.

Fig 7 Creating the material Card

6. Creating the section card

        The section card is created for the shell elements using the keyword * Section_Shell. The Thickness and the element form are assigned in the card.

Fig 8 Creating the Section card

7.Assigning the Section and the material to the Parts

       The SectionID and the Material ID for the respective parts are assigned in the keyword *PART.

Fig 9 Assigning the Section and the material to the respective Parts

8. Creating the DATABASE for the output

        The database for the output is created using the keywords *DATABASE_ASCII & *DATABASE_D3PLOT. In the keyword *DATABASE_ASCII , the options for plotting the GLSTAT, MATSUM and JOINTFORCE are checked.

Fig 10 Creating the ASCII card

Fig 11 Creating the binary_d3plot card

9. Creating the control termination card for the simulation runtime

         The simulation runtime is assigned using the keyword *CONTROL_TERMINATION and entering the ENDTIME for which the simulation is to be run.

Fig 12 Creating the Control termination card for the simulation runtime

CASE 2 : CREATING THE CYLINDRICAL JOINT

          All the Steps in this case are similar to the Case-1 except that steps 1,2 ,3 & 4. In place of those steps, the following steps are executed.

1. Creating two pairs of Co-Incident nodes forming the axis for the Cylindrical joints

         Two pairs of Co-Incident nodes are created along the axis of the Concentric cylinders. Each node in a pair belong to two different cylinders.

Fig 13 Creating Two Pairs of Co-Incident Nodes

2. Creating the CNRB'S(Constrained Nodal Rigid Bodies)

        Each different node of the Coincident pairs is used for creating CNRB with different Cylinder. Suppose, the nodes 449 and 450 are coincident then  using the Node 449, the CNRB is constructed for the Cylinder-1 and using the node 450 the CNRB is constructed  for the Cylinder-2. Hence, a total of four CNRB are constructed using the create entity tool bar. One of the coincident node becomes the parent node where as the other four nodes are chosen to be as the child nodes. 

Fig 14 Creating the CNRB for both the Cylinders

3. Creating the Cylindrical Joint

          The Cylindrical joints are created by using the keyword *Constrained_Joint_Cylindrical. The Parent nodes of the CNRB are entered in the card in order to create the Cylindrical joint. N1 and N3 are the parent nodes connecting the Cylinder-1 where as the Nodes N2 and N4 are the parent nodes connecting the Cylinder-2.

Fig 15 Creating the Cylindrical Joint

Fig 16 Cylidrical joint having realized

4. Applying the Boundary Conditions

      i. Applying Single Point Constraint to the Outer Cylinder

               The Node belonging to the Outer Cylinder i constrained in all degrees of  freedom using the keyword *BOUNDARY_SPC_NODE.

Fig 17 Constraining the Outer Cylinder in all degrees of freedom Using keyword SPC_Node

      ii. Applying the Prescribed Motion Set to the Inner Cylinder

              The Nodeset belonging to the Inner Cylinder is subjected to the rotational displacement it's own axis i.e, about the x-axis using the keyword *BOUNDARY_PRESCRIBED_MOTION_SET. The curve for describing the rotational displacement with respect to time is defined and assigned in the card. The flag for the displacement is entered along with the flag for the rotational motion in the x-direction.

Fig 18 Applying the Rotational motion to the Inner Cylinder

  iii. Applying the Translational motion to the Inner Cylinder

         Using the same card, the translational motion is added to the inner cylinder. The similar nodeset is used in card for imparting the translational motion. The flag for the translational motion and the displacement in the x-axis which also happens to be the cylindrical axis is entered in the card. The Load curve describing the translational motion is defined and assigned in the card.

Fig 19 Applying the translational motion in x-direction to the Inner Cylinder

CASE 3 : CREATING THE SPHERICAL JOINT

    All the steps in this case are similar to the Case-1 except 1,2,3 and 4. The following steps are to be executed in place of these steps 

1. Creating a pair of Co-Incident Node

         A pair of Co-Incident nodes is created exactly at center of the concentric Spheres. Each node belongs to different Sphere.

Fig 20 Creating a pair of Co-Incident node at the center of the Spheres

2. Creating the Constrained Nodal Rigid Bodies (CNRB)

               Each different node of the Coincident pair is used for creating CNRB with different Spheres. Suppose, the nodes 306 and 307 are coincident then  using the Node 306, the CNRB is constructed for the Sphere-1 and using the node 307 the CNRB is constructed  for the Sphere-2. Hence, a total of two CNRB are constructed using the create entity tool bar. One of the coincident node becomes the parent node where as the other nodes are chosen to be as the child nodes. 

Fig 21 Creating the CNRB for the sphere using the Co-Incident nodes

3.Creating the Spherical Joint

       The spherical joint is created using the keyword * CONSTRAINED_JOINT_SPHERICAL.The Parent nodes of the CNRB are entered in the card in order to create the Spherical joint. N1 and N2 are the parent nodes connecting the Sphere-1 and Sphere-2.

     

Fig 22 Creating the Spherical Joint

Fig 23 Spherical joint having Realized    

4. Applying the Boundary Conditions

       i.Applying the SPC to the Outer Sphere

               Using the keyword *BOUNDARY_SPC_SET, the Outer cylinder is constrained in all degrees of freedom

    

Fig 24 Constraining the Outer Sphere in all degrees of freedom

        ii. Applying the Prescribed Motion Set to the Inner Cylinder

                The rotational displacement is imparted to the inner Sphere using the keyword *BOUNDARY_PRESCRIBED_MOTION_SET. The nodeset belonging to the Inner Sphere is assigned the rotational displacement . The flag for the Rotational displacement about the x-axis and the displacement value is entered in the card. The load curve describing the rotational displacement with respect to the time is defined and assigned in the card.

Fig 25 Applying the Prescribed motion set to the Inner Sphere

CASE 4: CREATING THE TRANSLATIONAL JOINT

                All the steps in this case are similar to that of the CASE-1 except 1,2,3 and 4. Instead of these steps, the following steps are executed

1. Creating the Three pairs of Co- incident Nodes

           Three pairs of Co-Incident Nodes are created along the axis of the two Co-axial Rectangular Boxes using the node edit option in the Mesh Tool. 

Fig 26 Creating the Three Pairs of Co-Incident Nodes along the axis

2. Creating the Constrained Nodal Rigid Bodies (CNRB)

               Each different node of the Coincident pair is used for creating CNRB with different Boxes. Suppose, the nodes 1355 and 1356 are coincident then  using the Node 1355, the CNRB is constructed for the Box-1 and using the node 1356 the CNRB is constructed  for the Box-2. Hence, a total of Six CNRB are constructed using the create entity tool bar. One of the coincident node becomes the parent node where as the other nodes are chosen to be as the child nodes. 

Fig 27 Creating the CNRBs

3. Creating the Translational joint

                 he spherical joint is created using the keyword * CONSTRAINED_JOINT_TRANSLATIONAL.The Parent nodes of the CNRB are entered in the card in order to create the Translational joint. N1, N3, N5  are the parent nodes connecting the Box-1  where as the Nodes N2, N4 and N6are the parent nodes connecting the Box-2.

Fig 28 Creating the Translational Joint

Fig 29 Translational joint having realized

4. Applying the Boundary Condition

     i. Applying the SPC to the Outer-Box

            The Outer Box is constrained using the keyword *BOUNDARY_SPC_SET. The nodeset belonging to the outer Box-1 is assigned for the Single Point constraint in all degrees of freedom.

Fig 30 Constraining the Outer box in all degrees of freedom

     ii. Applying the Prescribed motion to the Inner Box

            The Prescribed motion is applied to inner box using the *keyword BOUNDARY_SPC_SET. The flag value for the  translational motion and the displacement is entered in the card. The curve describing the displacement motion with respect to time is defined and it is assigned in the card.

Fig 31 Applying the displacement motion to the Inner Box

RESULTS :

NOTE: *All the Animation files of the Simulation run are in form of PPT file which has been attached with this report.

1. Simulation of the Revolute joint

INFERENCE:  The simulation shows that the Plate-2 rotates about the axis created by the coincident nodes as the plate-1 is fixed due to the Constraint in all degrees of freedom. This way the revolute joint ensures that the plate rotates about an axis without the need for creating a local coordinate system and making the plate rotate about it.

2.Simulation of the Cylindrical Joint 

  INFERENCE:     The simulation shows that the Inner Cylinder is able to rotate about the same axis as well as translate  and hence allows the Cylinders to have reative motion about the same axis. This type of motion can be used for depicting the motion of the Screws

3.Simulation of the Spherical Joint

  INFERENCE: The simulation shows that the Inner sphere is able to have relative motion with respect to the Outer sphere and remain concentric irrespective of the direction of the rotation given to the Inner sphere.

4. Simulation of the Translational joint

  INFERENCE: The simulation shows that the Inner Box is restricted to having only translational motion along the centerline and both the rigid bodies are stuck together.

 

CONCLUSION :

1. All the joints were realized successfully using the relevant cards.

2.All the Joints were demonstrated successfully.