Week 4- Challenge
CREATION OF 1D ELEMENT ON THE GIVEN COMPONENT FOR
GIVEN CROSS-SECTION AND DEGREE OF FREEDOM (DOF).
OBJECTIVE / AIM : To create a 1 dimensional (1D) element (Bar, beam, rod, springs) on the given component along with the given "area of cross-section" and "degree of freedom" .
CAD MODEL : Component represented below is the given cad model on which we have to create the 1d element.
CAD MODEL : PARALLEL BRACKET.
PROCEDURE : Before getting into the procedure let us try to divide the given "cad model" into two different components :
(A) TWO DIFFERENT COMPONENTS : 1. Upper bracket (or) name it as bracket-1.
2. Lower bracket (or) name it as bracket-2.
(B) Always try to divide (or) separate the given model into different components irrespective of the operation going to be performed whether
may be meshing (or) mid-surfacing. It will be always helpful when we do this.
(C) Now let us furthur proceed to complete our procedure step by step.
STEP-1 IMPORT MODEL :
(a) Download the model given for challenge and check which type of file format it belongs to.
(b) Now after checking , go to the file and select import option and select geometry then , click on the model which you want to import.
STEP-2 CREATION OF MID-SURFACE :
(a) After importing the model , the first step is to create the midsurface for the given model.
(b) For the creation of midsurface click on geometry in the menu page (or) the panel area.
(c) Click on the midsurface options and click auto extraction.
(d) Then click on the surface that you want to extract and the midsurface is created.
(e) Whenever you create a midsurface please try to create new components. For example in this case we have two components so create two new components
and delete the old (or) the original one.
(f) For one component just rename the "midsurface as bracket-1" and for the other rename it as "bracket-2".
(g) Delete the original components once you have created a new one.
(h) There is also other option where you can transfer or duplicate your mid surafce into the new component you have created.
(i) Here for the second component (or) the bracket-2 you can transfer the midsurafce into brcaket-2 and the command is click on the tool option
in the menu page then click on the "organize" command and select the surface that you want to move into bracket-2.
(j) Now the mid surface is created for both the components which looks so ideal when we do meshing.
(k) Below i have represented the midsurface images of the given components.
(l) Delete the solid entities after creating the midsurface by clicking the delete option.
EXTRACTION OF MIDSURFACE
CREATION OF MIDSURFACE
1.COMMAND TO MOVE THE MIDSURFACE TO BRACKET-2 : MENU PAGE / TOOL / ORGANIZE / COLLECTORS / SURFACES/ MOVE.
2.TO GET THE SURFACE OPTION CLICK ON THE DOWN ARROW NEXT TO ELEMENTS.
STEP-3 GENERATION OF MESH OVER THE CREATED MIDSURFACES :
(a) After deleting the solid entities , we are going to generate mesh over the created midsurfaces.
(b) Before going for a 2d meshing , autocleanup your midsurfaces.
(c) Autocleanup option is provided in the geometrical menu page.
(d) After geometric cleanup go for 2d meshing.
(e) Click on the quick edit option in the geometry menu page and go for "washer split" option and give a offset of 5mm then create the washer split.
(f) Once the washer split is created, click on the 2d option in the menu page and it will take you to the page where you have to pick the command line automesh.
(g) Before meshing give the required inputs such as surface that need to be meshed , element size and mesh type then click on mesh.
(h) Give the element size as 10 and go for mixed meshing if the meshing is not fine then choose element size as "8" and give mixed type meshing.
(i) Dont worry about the quality of the mesh since we are not introduced to it.
WASHER SPLIT CREATION OVER THE MIDSURFACES USING QUICKEDIT.
MIDSURFACE DURING MESHING PROCESS.
MESHED MIDSURFACES.
STEP- 4 CREATION OF MATERIAL AND UPDATION OF PROPERTY ASSOCIATED TO THE MATERIAL CREATED :
(a) For 3d representation we need to assign a thickness , for that we should create a material.Since we are creating 2d shell elements ( shell elements are the 2d
representation of the 3d elements) we need to create a material so that we can project it as 3d.
(b) Click the right mouse button in the space provided above the status bar (or) below the components you created.
(c) Now the material is created.
(d) Specify the material type , let us specify it as steel and create a property in order to associate with the "material and the components".
(e) For creating the property , click on the right mouse button below the material you created.
(f). Create two properties since we have two components and again name them as "bracket-1 and bracket-2".
(g). Now associate the property created with the material (steel) .
(h). Again associate the components with the properties so that now your "component will be made of steel".
(i). To do that click on the component bracket-1 and down you can see a dialogue box indicating which property would you want to enter and
click on property "bracket-1" to associate with the component-1 and once you assign the property it will automatically assign the material steel
since you have already associated it with the property. Do the same for bracket-2 also.
(j). This is the way with which you can create a material and associate with the components you created.
DIALOGUE BOX FOR ASSOCIATING THE MATERIAL DIALOGUE BOX ZOOMED VERSION
WITH THE COMPONENT. I HAVE MARKED THE CARD IMAGE IN PENCIL AND IT
IS REPRESENTING STEEL.
(k) In the dialogue box check the "card image" ( card image is the identity given by the solver and it varies for different solvers.) Make sure your card image is
PSHELL since we perform our operations under optistruct it shows Pshell. Pshell represents that we are going to create 2d representation of the
3d elements.
STEP-5 CREATION OF 1D ELEMENTS ON THE CREATED MIDSURFACES WITH GIVEN CROSS SECTIONS AND DEGREE OF FREEDOM :
(a) 1D elements to be created on the midsurfaces : ROD , BAR , BEAM AND SPRING.
(b) To create 1d elements click on 1d keyword in the menu page (or) the panel area.
(c) First let us create the links of the rbe2 and rbe3 elements.
(d) When cluster of elements are created it is known as "link".
STEP-5.1 CREATION OF RBE2 LINK :
(a) To create rbe2 elements click on the 1d keyword in the menu page.
(b) Then click on rigids also known as rbe2 , because it is the "stiffest element" that can be used in hypermesh.
(c) Sharing (or) the distribution of the load is uniform throughout the links irrespective of the position of the dependent nodes.
(d) Then click on an independent node , choose nodes by path and give calculate by nodes and enter the dof.
(e) Rbe2 element is created.
(f) Image representing the creation of an rbe2 link.
(g) Data given : For rod element dof=x,y,z translational.
DOF : XYZ TRANSLATIONAL
LINK : RBE2
ELEMENT : ROD
STEP-5.2 CREATION OF RBE3 LINK :
(a) To create rbe3 elements click on the "1d" keyword in the menu page.
(b) Then click on rbe3 elements option and create dependent node anywhere on the second circular surface.
(c) Then click on calculate by nodes and nodes by path , then create a rbe3 element.
(d) Select the corresponding dof for the type of 1d element to be created.
(e) Now our rbe3 link is created.
(f) Image representing the creation of an rbe3 link.
(g) Data given : For beam element dof=all the 6 dof.
For bar element dof= x,y translational and rotational.
DOF : ALL
LINK : RBE3
ELEMENT : BEAM
DOF : XY TRANSLATIONAL AND ROTATIONAL
LINK : RBE3
ELEMENT : BAR
STEP-5.3 CREATION OF ROD ELEMENT WITH RBE2 LINK :
(a) Elements to be created : ROD , BEAM , BAR AND SPRING.
STEP-5.3.1 CREATION OF ROD ELEMENT WITH THE GIVEN AREA OF CROSS SECTION :
(a) In order to create a rod element click on the 1d keyword in the menu page.
(b) Click on the hyperbeam option to create the cross sectional area for the rod.
(c) Enter the given dimensions in the dilaogue box located left to the cross section and rename it as rod.
(d) Now you will get the required area of cross section.
(e) Now return back to the home page and click on 1d keyword in menu page.
(f) Click on the "rod element" and create the rod.
(g) Then create a new property called rod as we did before and associate it by clicking on the property rod.
(h) Rod section is created.
CARD IMAGE : PROD
MATERIAL : STEEL
BEAM SECTION : ROD
(i) Click on the rod property to associate it with the material and cross section that you have created in the hyperbeam.
(j) Select "PROD" as the card image and choose the area of cross section.
STEP-5.3.2 CREATION OF BEAM ELEMENT WITH THE GIVEN AREA OF CROSS SECTION :
(a) To create a beam element first we have to create a standard I cross section for the beam.
(b) As you did before , go to the hyperbeam option and select standard section.
(c) After selecting the standard section , select standard section library as hypermesh.
(d) Then select the I-section and enter the dimensions.
(e) Cross section is ready and now return to the homepage.
(f) Now create a property called beam and associate with the 1d element bars.
(g) Click on the node A and node B , then give the element type as cbeam and the corresponding property as beam.
(h) Click on the card image and assign it as "PBEAM"
(i) Beam section is created.
CARD IMAGE : PBEAM
MATERIAL : STEEL
BEAM SECTION : BEAM
STEP-5.3.3 CREATION OF BAR ELEMENT WITH THE GIVEN AREA OF CROSS SECTION :
(a) To create a bar element click on the hyperbeam tool (or) option in the 1d menu page.
(b) Click on the standard section library as "optistruct".
(c) After selecting the optistruct option , go for standard section type as cross.
(d) Give the dimensions and the cross section is ready.
(e) Now return to the home page and create a property for the bar section named as bar.
(f) Then go to the bar option and again select the nodes , assign the property as bar and choose the element type as cbar.
(g) In the dialogue box assign the beam section as cross bar and the material type as steel.
(h) Now the bar element is created..
CARD IMAGE : PBAR
MATERIAL : STEEL
BEAM SECTION : BAR
HYPERBEAM IMAGES OF DIFFERENT ELEMENTS ALONG WITH THE GIVEN CROSS SECTION :
[A] . AREA OF CROSS SECTION OF THE ROD ELEMENT :
AREA OF CROSS SECTION : BOX
STANDARD SECTION LIBRARY : HYPERMESH
DIMENSIONS TO BE ASSIGNED : ABOVE DIMENSIONS.
[B]. AREA OF CROSS SECTION FOR THE BEAM ELEMENT :
AREA OF CROSS SECTION : I-SECTION
STANDARD LIBRARY SECTION : HYPERMESH
DIMENSIONS TO BE ASSIGNED : ABOVE DIMENSIONS
[C]. AREA OF CROSS SECTION FOR THE BAR ELEMENT :
AREA OF CROSS SECTION : CROSS
STANDARD LIBRARY SECTION : OPTISTRUCT
DIMENSIONS TO BE ASSIGNED : ABOVE DIMENSIONS
STEP-5.3.4 CREATION OF SPRING ELEMENT :
(a) To create a spring element click on the 1d option in the menu page (or) the geometric panel.
(b) Create a property named as spring and associate it with the spring element.
(c) Create the nodes wherever you want and select the degree of freedom.
(d) After entering the degree of freedom (only one dof is allowed for the spring element) enter the property and the element type as "celas".
(e) Then create the spring element.
(f) There is no need to create cross sections since it is not mentioned.
ELEMENT TYPE : CELAS
DEGREE OF FREEDOM : DOF1
STEP-5.3.5 DISTRIBUTION OF MASS OVER THE RBE2 ELEMENT :
(a) To distribute (or) share the mass over the created rbe2 link click on the option masses in the 1d keyword in the menu page.
(b) Select the node and enter the magnitude as 10.
(c) Now click on create and thus the mass is distributed over the rbe2 elements.
MAGNITUDE OF MASS : 10
PROPERTY : ROD
ELEMENT TYPE : CONM1
STEP-5.3.6 1D DETAILED ELEMENT REPRESTATION (OR) DISPLAY :
(a) After creating all the 1d elements we need to represent it in 3d.
(b) For that click on the above tool (or) the icon represented in the image.
(c) Then click on the "1d detailed element representation".
Now finally we have completed the procedure.
DIFFERENCE BETWEEN RBE2 ELEMENT AND RBE3 ELEMENT :
(A) RBE2 ELEMENT : 1.It is considered to be the stiffest element used in the hyperworks.
2.The load distributed over the rbe2 links are shared equally irrespective of the location of the nodes.
3.It is also known as "rigids".
(B) RBE3 ELEMENT : 1.It is not an stiffer element.
2.The load distributed are not shared equally.
RESULT/CONCLUSION : 1. Learnt (or) learned to create 1d elements on the given cad model.
2. Learnt to create a midsurface and obtained the uses of midsurface ( by midsurfacing we are able to reduce the storage of the nodes, easy for analysis).
3. Obtained knowledge on using hyperbeam for creating the cross sectional areas for the different elements.
4. Obtained knowledge on creating a material and associating the material with the created property.
5. Learnt to do a 2d meshing in the midsurfaces.
6. Gained knowledge on creating mass and distributing it over an rbe2 element.
7. Obtained knowledge on knowing the difference between rbe2 and rbe3 link (or) elements.
8. Learned to represent 1d elements in a 3d form.
9. Obtained knowledge on creating different 1d elements such as beam,bar,rod and spring.
10. Learned the differences between "rod,bar and beam element".
FINAL IMAGES/ RESULTANT IMAGES ALONG WITH THE GIVEN AREA OF CROSS SECTION AND DOF :
{A}. TOP VIEW :
CROSS SECTIONAL AREA OF ROD : BOX
CROSS SECTIONAL AREA OF BEAM : I-SECTION
CROSS SECTIONAL AREA OF BAR : CROSS
{B}. FRONT VIEW / FINAL IMAGE :
{C}. ISOMETRIC VIEW :