PREPROCESSING ON A HOOD COMPONENT BY USING ANSA

AIM :

        To Performing a preprocessing operation on a given hood component by using ANSA software.

OBJECTIVE :

       1) Checking the entire given geometry and cleanup the geometrical Error if required.

       2) Extracting the Middle Surface from the parent component.

       3) Set the quality parameter and Mesh element Parameters.

       4) Performing a Meshing Operation on a surface as per given quality Criteria.

       5) Assigning the properties and Thickness to the respective component.

CAD MODEL :

       Open the ANSA software, import the appropriate file which is Hood by using open graphical user interface option. Once open the hood model, it will looks like as shown in the below image.

       Hood model consists of five components which is one Latch Reinforcement, Two Hinge Reinforcement Component, Inner Panel and then Outer Panel.

        

i) Latch Reinforcement :

       

ii) Hinge Reinforcement :

       

iii) Outer Panel :

       

iv) Inner Panel:

       

PROCEDURE FOR ACHIEVING THE OBJECTIVE :

I) Checking the Geometry :

      Before going to meshing on component, we have to checking the given geometry. Inorder to checking the geometry, We have click the "Checks" option and followingly select the "Geometry" option.

      Make sure set the Visible for "Execute on" which means automatically selecting which are visible from the graphical window.

      Afterthat, Click the "Execute" option, a inbulid algorithm will comes finding the errors on a geometry. If any error are presented in the visible model, it will showing up in the same window what error and where it is. Inorder to rectify the geometrical errors, right click to select all active error which are shown and click the fix option, it will automatically fix those issues as mush as possible in properly manner.

       A Errors showing depends on our given template, in this case ANSA check have own default checking option like as shown in the below image.

       If there is no geometrical error from the visible part, then we gonna next stage in the preprocessing.

i) Latch Reinforcement :

      In this latch reinforcement component, there's no geometry error on it. We pass this component to next stage which is middle surface extraction.

      

ii) Hinge Reinforcement :

     In this Hinge reinforcement component, there's no geometry error on both side. So, that we pass this component to next stage which is middle surface extraction.

     

iii) Outer Panel :

     Similarly, as same as in prevoius two, there's no geometry error on outer panel. So, we pass this component to middle surface extraction.

     

iv) Inner Panel :

     In this component has vice versa to previously mentioned component. This component have some errors on it, which is for Needle face.

     

     Select any one of the error from which is presented on a tab, followingly right click on it. We have one option called "Show Only" which means it will showing exact error place from our component.

     If the Needle faces is presented on a model, by results it will failing for minimum element length criteria. So, that we have to avoid such thing.

     Inorder to clean those errors, we have two option in our hand. One is Manual fix and another one automatic fix. In this case, we Confidently gonna automatic fix, because as we noticed from the check tab which "Yes" for "Auto fix".

     Inorder to do fix those thing in automatically, we have to select all errors which are shown up and right click to fix. Afterthat, ANSA algorithm quickly suppressed any one of double cons.  

     

     If we want to cross check, we have to rerun on it. Now, there's no errors is showing up as we seems before.

     

II) Extracting the middle surface from the parent component :

     Middle surface means, a surface exactly created between the top & bottom surface from the parent component. It will helps us to reduce the computer calculating time and also reducing the storage space.

     We have two option in our hand, one is automatic mid generation and another one manual middle surface generation.

     In this case, we has to do generate middle surface by using manual method. If we use automatic mid surface generation algorithm, by result we lost the parent component.

     Before gonna generating the middle surface by using offset option, make sure we measured the appropriate thickness on a respective component.

     Keep the offset value which is half a thickness distance of respective component thickness.

i) Latch Reinforcement : 

     Select the "Topo" module, followingly choose the "offset" option with choose "Select" sub option under which "faces" category.

     Select the top surfaces, click the middle mouse button and then give the offset distance which is 0.6. Make sure check the orientation of the component, grey color represents positive and yellow color represents negative. By depends on orientation, sign will changed.

     

    After extracting the middle surface, it will looks like as shown in the below image.

    

ii) Hinge Reinforcement :

    Select the top surface and click the middle button from mouse, followingly give the offset thickness which is 0.6.

   

   After creating the middle surface for hinge component, it will looks like as shown as below image.

   Similarly, we have to do remaining on another one hinge portion.

   

iii) Inner Panel :

   Similarly, select the top surface of the inner panel component and give the offset distance which is half a thickness of respective parent component thickness is 0.375.

   

   After extracting the middle surface for inner panel, it will looks like as shown as below image.

   

iv) Outer Panel :

   Simiarly, select the top surface of the outer panel component and give the offset distance which is half a thickness of respective parent thickness is 0.375.

   

  After extracting the middle surface for outer panel, it will looks like as shown in the below image.

  

III) Quality Parameter and Mesh Element Parameters :

    We have to give the quality parameter which are Target length, minimum target length and maximum target length like as shown in the below.

    A Meshing algorithms will distrize the model with respect to given this values.

    

    Make sure set the quality criterias which will help us to visualize finite element model whether it's fails any of these.

  

IV) Perform Meshing Operation :

    Basically, To divide the entire model into infinitesimal control volume, that framework is called meshing. This process is called discritization.

    Make sure set the resolution for which two node distance between is equal to target element length. 

    ANSA have varieties option for which descritize the model, each and every meshing option have different algorithm. In this case, we have to use "Best" option to which generating the FE elements on a each & every surface.

    Select the any suface, click middle mouse button and then element are created. If created elements are improper, we have remeshing on a elements by using "Improve" or "reconstruct" option. 

    Also, While doing on meshing, we have keep in mind about element qualities. If any elements are failing due to any one of the parameter, we have takecare on that element untill or unless element should not failing.

i) Latch Reinforcement :

       A Mesh elements are created on a latch reinforcement mid surface as per meshing thump rule. A Mesh elements are satisfied in all given element parameters.

       By using "Best" meshing algorithm to which generate the elements on surface by surface. If elements are not proper, we have to remeshing on that particular area again and again until we capturing the proper mesh flow.

       After done the meshing on latch mid surface, it will looks like as shown in below image.

      

    

ii) Hinge Reinforcement :

     Before Topology Cleanup :

     Distance between the two double cons were less than minimum element length. If we keep as it is in the mid surface while meshing , by results elements are failing due the minimum element length parameter. 

     

     After Topology Clenup :

      Inorder to rectify that issue, we have to supress the any one of the line by using "Cut" option. After supressed the line, it will looks like as shown in below.

     

     Mesh :

     By using "Best" option to create the mesh elements on the hinge mid surface. After done the meshing operation on a surface, it will look like as shown below image.

     Finite elements are satisfied in all quality parameters.

     

iii) Inner Panel :

    Before Topo Cleanup :

     We have supress few double cons and subsequently to create new double cons by using cut option. 

     Without topology cleanup on a component, it will looks like as shown in the below two images.

     

     

    After Topo Cleanup :

     After suppressing some few double cons and newly create some few double cons, it will looks like as shown in the below two images.

    

    

     Similarly, we have to do where ever the topology cleanup is required.

    Meshing :

     Similarly, we have to do meshing operation on surface by surface  by using "Best" option to which capturing the best mesh flow. If the elements are not proper, we have to improve the mesh flow by remeshing again and again whenever we get the proper mesh flow on a surface.

     After done the meshing on a half a surface, it will looks like as shown in the below image. 

    

    Once done the meshing on a half, we have to use symmetry sub option under which translate option to copy the FE model & surfaces on another half.

    After copying the FE's on a another side, it will looks like as shown in the below.

    

       After copying to another side, we have to generate the meshing elements on a unmeshed surface.

    

iv) Outer Panel :

    Without Topology cleanup : 

    If We perform a meshing operation without any topological cleanup, by result lot of trias are created and also mesh flow should not be proper. Inorder to rectify those issues, we have to manually rearrange the double cons without any surface distortion.                                                                                                                 

     

    In the hemming portion, all elements are failing due to the minimum element length criteria. Inorder to restrict that, we have to supress the double cons on a both sides and keep middle line alone.

         

    With Topology Cleanup :

      After recreate the new construction lines, it will looks like as shown in below image. Now, If we perform meshing operation on it, lot of trias are reduced and capturing the proper mesh flow throughout the surface.

     

      We suppress those double cons on both ends and keep the double con at middle like as shown in the below image. Now, If we create the mesh, there's no elements are failing due to any given element parameters.

     

      By using few meshing algorithm to captured the proper mesh flow on it like as shown in the below.

    

     Once, we done the meshing on half portion, we have to copying those FE's into another half portion by using 3 point symmetry option under which translate option.

     After copying to another portion, it will looks like as shown in the below image.

   

    

V) Assigning the thickness :

    Inorder to assigning the thickness, make sure we put the thickness values to the corresponding property identity.

    Without thickness : 

     

     With thickness : 

     Inorder to visualize the thickness from the middle surface, we have check the "Draw shell as solids" under which "Presentation parameters" and apply on it.

     

CONCLUSION :

     Successfully done the preprocessing operation on a given hood model like Checking the geometry error from the model, Middle surface Extraction from the parent component, Meshing and then assigning the thickness to the middle surface.