Assignment 2-RADIOSS Engine File Editing & 3D Meshing Challenge

Ans 1.  Young's Modulus rail component E = 210000.0 N/mm2

            Density Of the rail component Rho= 0.0078 g/mm3

            Speed of sound in rail Component =`sqrt(E/rho)`

         Hence, Speed of sound in the rail component= `sqrt(210000/0.0078)`

              Speed of the sound in the rail component = 5188.7452 mm/sec

Ans 2.  Length of the rail L= 1000 mm  

            Time for the Shock wave to travel from one end to another = L /`sqrt(E/rho)`

                                                                                                  =1000/5188.745

Ans 3. Time for the Shock wave to travel from one end to another in the rail component =192.724 ms  

Ans 4. The neccessary changes in the engine file have been made so that the stress wave can be monitored,       moving from one end of the rail to the other during impact. The termination time has been set at 200 ms.

Ans 5. The frequency of the animation output has been set to a time of 10 ms so that it can give 20 animation steps.

Ans 6. The print has been changed to -10 in the engine file.

Ans 7.

Objective :

            3d meshing of the Given models for the Given Quality criteria 

         1.Target tet size= 5mm

         2.Hex Size = 10mm

         3. Tet collapse = 0.15

 Fig 1 Model 1

Fig 2 Model 2

Procedure :

•  Importing the Geometry:

       The model is imported Using the Import geometry tool in the Standard tool bar. The file type to be imported is chosen as Step file.

Fig 3 Importing the Step File

• Creating the tetra mesh for the Hub by creating the 2d tria mesh

            1. Creating the 2d tia mesh on the hub component :

                   All the Surfaces on which the mesh is to be created is chosen along with the mesh element type as tria. The Element size is entered as 5mm.

Fig 4 Creating 2d tria mesh

Fig 5 2d tria mesh

           2.Creating the 3d mesh on the Hub

                 a) The tetra mesh parameters in the tetramesh tools from the 3d tools panel are entered.The tetra mesh parameters are set especially the tet collapse value at 0.15.

 Fig 6 Tetra mesh in 3d tools panel

Fig 7 Entering the tetra mesh parameters

           b) The tetra mesh is created using the  2d tria elements . To check whether the tetra mesh has been created, mask few of the elements.

Fig 8 Creating the tetra mesh   

  Fig 9 Tetra mesh Created 

           c) The elements  are checked for tet collapse value of 0.15  through the check element tool in the tools panel.

  Fig 10 Checking for Tet Collapse  

•      Creating the Tetra mesh Using the volume tetramesh Option for the Cover.

                1.  The Volume tetramesh option in the tetra mesh tool is chosen and all the required parameters such as  element size,minimum element size,  2d element type , 3d element type and the order of the elements are chosen.  The surface on which the mesh are to be created are chosen and the mesh button is hit.

    Fig 11 Creating the tetra mesh Using the Volume tetra mesh 

Fig 12 Tetra mesh created using the Volume tetra mesh

         2.Checking for theTet collapse and remesh the Elements failing for the tet collapse value of 0.15

              a) Checking for theTet collapse

                      The elements failing for a tet collapse value of 0.15 are determined through the check elements tool in the tools option. 

Fig 13 Checking the element for tet collapse

              b) Remeshing the elements failing for tet collapse till no elements fail for the tet collapse value of 0.15

                            The elements failing for the tet collapse are saved and using the mask option in the tools panel these elements are retrieved and all the other elements are masked. The adjacent elements to these unmsaked elements and remeshed so that no elements fail for the tet collapse.

Fig 14 Saving the failed elements      

Fig 15 Isolating the elements failing for the tet collapse

Fig 16 Remeshing the element for the tet collapse

         Those elements which fail even after remeshing are rectified manually by using the translate command. 

Fig 17 Ensuring no element fails for tet collapse

• Creating the Hexa mesh for the Arms Bracket

           1. Creating the Hexa mesh for the base of the arm bracket by Offset element option

                a) Creation of the 2-d element on the face of the base.

                        The 2d-elements of the size 10 mm and mixed type are created on one of the faces of the base. 

Fig 18 Creating 2-d elements on one side of the base

         b) Offset the elements in order to create 3-d hexa elements. 

                   All the elements created are offset to the opposite surface in order to create the 3-d hexa mesh through element offset option in the 3-d tools panel. The Solid layer option is chosen and the the adjacet surfaces are chosen for the geometry to be followed. Since the thickness is 25 mm hence the thickness is given as 25 mm and 5  number of layers of the offset elements are to be created between the two opposite sides of the surfaces. 

Fig 19 Offsetting of the 2-d elements to create 3-d hexa mesh

Fig 20 3-d hexa mesh created by offsetting of the 2-d elements

        2. Creating the Hexa mesh for the arm curve of the arm bracket by Spin element  

             The 3-d hexa mesh are created by spining the 2-d elements of the cross section along the curve by using the Spin elemets option in the spin tool from the 3-d tools panel.

      The base point is taken as the centre point of the curve and the  axis of rotation  is the x-axis and the degree of rotation being 90 deg. The number in the on spin defines the number of layers of the 3-d elements which 25.

Fig 21 creating the 3-d mesh using the Spin Elements

Fig 22 the 3-d mesh created using the Spin Elements

           3. Creating the 3-d hexa mesh on the Sraight arm Using the Linear solid option 

                    The 3-d hexa mesh are created by creating equal number of 2-d elements on the opposite faces and defining the source elements and the destination elements.

Fig 23 Creating the 3-d elements using the linear solids

Fig 24 3-d Hexa mesh created on the straight arm

       4.Creating the 3-d mesh on the Boss  through solid map 

            a) Creating the 2-d elements on one of the cyliderical face

Fig 25 Creating 2-d elements on one of the faces of the boss    

           b) Creating the 3-d hexa mesh using the by solid map

                   The 3-d hexa mesh are created by defining the destination geometry, elements to  be dragged, the nodes & the geometry along which the the elements are to be dragged.

 Fig 26 Creating 3-d hexa mesh using solid map

Fig 27 3-d mesh created on the boss through solid mapping

 Result:

1. The Model-1 was meshed successfully with Tetra mesh & mesh size being 5mm.

2. The Model-2 was meshed successfully with hexa mesh of size 10 mm

3. All the elements in both the meshed models had a Tet collapse value less than 0.15

Fig 28 Completed Model-1

 Fig 29 Completed Model-2