Mid Surface of Side Door

AIM:-

1. To Extract the mid-surface manually & mesh the geometry with quality.

2. To Extract mid-surface Automatically and mesh the geometry with quality.

3. Then Finally with the combination of both Extract auto mid-surface and manually mid-surface and then mesh the geometry with quality.

PROCEDURE:-

The following procedure will be followed :

GEOMETRY CLEAN-UP:-

  • The imported model is checked for the geometry errors using the checks manager. If there are any errors, it should be corrected and the geometry is made clean.

EXTRACTING THE MID-SURFACE:-

  • Then the mid-surface should be extracted. It can be extracted either manually or automatically using appropriate methods.
  • It is based on the thickness variation and time constraints.
  • In the manual method, the faces are selected and the offset value is given.
  • In the automatic method, the mid surface is extracted in an FE model straight form.
  • For this the whole part is selected, maximum thickness value, target element size are given in prior.

ASSIGNING PID'S & THICKNESS:-

  • Now the regions with different thicknesses are assigned with different PID's and the thickness values are assigned accordingly.
  • This process can also be done by three methods which are again Auto, Manual, & Combination of both the methods.

MESH GENERATION:-

  • Then, if the mid surface is a CAD geometry, then the model has meshed with the target element size as Defined.
  • Because in the Auto method, the extracted mid-surface is already an FE model itself.

MEETING THE QUALITY CRITERIA:-

  • Now the mesh elements are corrected to meet the quality criteria specified below:

ELEMENT TYPE: MIXED

TARGET ELEMENT SIZE FOR ALL THE MODELS: 4MM

GEOMETRY CLEAN-UP:-

  • When the model is imported, it has a lot of topological errors.
  • The model is checked for any errors by checks manager, Hence it is found that there are a lot of single cons, triple cons, needle faces & cracks.
  • All those errors are corrected systematically one by one.

                                          WIREFRAME MODE

                                                SHADOW MODE

                                                     PID MODE

AFTER CORRECTION:-

                                       SHOWS AN ERROR-FREE MODEL

MID-SURFACE EXTRACTION BY AUTO METHOD:-

  • After correcting all the errors, the model is ready to be Mid-skinned, The options used are:

         GO TO : TOPO > FACES > MID-SURFACE > CASTING.

  • Then the whole model is selected and the target element size is given as 4mm and clicks ok, Then the middle surface of the whole model is extracted in the FE model as shown below:

  • Now the middle surface is checked using the following algorithm

        GO TO : TOPO > FACES > MID SURFACE > CHECK MIDDLE SURFACE.

  • Now ANSA compares the Extracted mid-surface with the original model if there is any deviation it will correct automatically.
  • To automatically assign PID's & appropriate thickness:

        GO TO  : TOPO > FACES > MID-SURFACE > CALUCULATE THICKNESS.

  • By using this algorithm ANSA will automatically detect the areas with the different thickness values and assign those values with separate PID's.

  • As seen in the above picture, the FE middle surface is assigned with the PID's and the thickness values accordingly.

MEETING THE QUALITY CRITERIA:-

  • As the mid-surface is already in the form of the FE model, now quality criteria are to be specified.
  • After assigning, there will be a number of elements OFF since they do not meet the mesh quality specified as below.

  • Each one of these should be corrected by using appropriate methods for each criterion. the most commonly used methods are :

  • As seen in the above pictures, all the mesh elements are met with quality criteria specified by the user and no elements are OFF.
  • This helps in obtaining accurate results during analysis.

MID-SURFACE EXTRACTION BY MANUAL METHOD:-

  • Unlike the auto method in which the whole model is mid-skinned at a go, But in a manual method each face is selected and it is been OFFSET depending upon its thickness by the user manually.

          GO TO : TOPO > FACES > OFFSET.

  • The mid-surface can be seen as follows:

  • The red con which is seen in the middle of the surfaces are the mid surfaces which are OFFSET by the user.
  • All these surfaces should be connected in order to form a single model.
  • First, the base surfaces should be OFFSET and are connected.
  • Then the ribs and other projected surfaces are OFFSET and are extended to meet the original mid surface.

         GO TO : TOPO > FACES > EXTEND

The OFFSET ribs can be seen in the below snapshot,

After OFFSETTING all the surfaces and connecting together, the whole mid-surface is formed as follows.

After this, each surface with different PID and the appropriate thickness values are given by checking the original surface thickness. The model with PID's assigned as follows:

MESH GENERATION:-

  • Now the mesh is generated with target element size as 4mm using the below algorithm.

        GO TO >MESH > MESH GENERATION > BEST > MIXED

  • Once the mesh is generated, quality criteria are specified as mentioned earlier.
  • Then the elements which are not meeting the quality criteria are corrected and in the end, no elements should be OFF as shown below:  

MID-SURFACE EXTRACTION BY COMBINATION OF AUTO & MANUAL METHOD:-

  • In this method, a different approach is followed, first, the whole model is mid skinned as did in the auto method.
  • Some of the missing entities and deformed surfaces are OFFSET manually and are connected to previously extracted mid-surface.

        GO TO : TOPO > FACES > MID-SURFACE > CASTING.

  • Then the whole model is selected and the target element size is given as 4mm and clicks ok, Then the middle surface of the whole model is extracted in the FE model as shown below:

As the extracted surface is in the form of the FE model, it should be converted to a surface geometry for further processes, To do so, the algorithm used is 

        GO TO > MESH > ELEMENTS > TO SURFACE.

Once it is converted to surface geometry, entities like the ribs are manually OFFSET by the user accordingly to the thickness values & then they are connected as shown below.

After this PID's are assigned properly and thickness values are also assigned.

MESH GENERATION:-

  • Now the mesh is generated with target element size as 4mm.
  • Then all the elements are corrected to meet the quality criteria as specified.

CONCLUSION:-

  • Extracting the mid-surface by Auto method took less than 8 minutes for the whole model and it also saves a lot of time, But the accuracy of the surface captured is very poor.
  • On the other hand, when doing it manually, the user can produce the mid surface with the best finish and dimensional accuracy, but it takes a lot of time.
  • Hence, using the combination of both would be the best choice for the mid-surface extraction method Because it saves time & Generates nearly accurate results.

Projects by Arun Gupta

Objective 3-D simulation in Converge CFD to compare the emission and performance characteristics for a CAT 3410 diesel engine with different piston bowl geometry. Open-W Piston Omega piston Introduction In previous years of research has shown that the different Read more

FULL HYDRO case set up PFI
Arun Gupta · 2019-09-29 10:38:28

Objective To simulate the full hydro setup of a Port Fuel Injected engine which uses Iso octane as the fuel. Introduction When fuel injection takes place due to the interaction of the liquid with the surrounding air there is a drag force which causes disturbances in Read more

Aim It is a flow simulation through a pipe to understand super-cycling in a conjugate heat transfer problem. Introduction The analysis type Conjugate heat transfer (CHT) allows the simulation of the heat transfer between Solid and Fluid  Read more

Aim Cleaning and Mesh the Mesh model to define the correct property ID. Introduction Hood is a covering part of the engine compartment which is also known as the bonnet. Acts as a engine unit protector, and protects from environmental issues. Protects passenger f Read more

Aim Study the effect of pressure and temp in Shock-tube. Introduction In a Shock Tube, the sudden expansion of a gas at high pressure into a gas at low pressure produces a plane shock wave that then propagates through a long-closed tube. The shock wave is used to pro Read more

Mesh the BMW M6 Model
Arun Gupta · 2019-08-06 17:24:20

Aim Cleaning and Meshing of the provided BMW M6 Model. Introduction As the car has several PID\'s there were many topological errors to clear and there are triple coons single coons as seen in the above model, the main aim is to clear those and to create a surface me Read more

Aim Cleaning the CAD model and Surface meshing the pressure Valve CAD model using ANSA. The problem in the Pressure Valve CAD Model I have observed in the cad model many problems are present. Surface missing Surface Interface Performed steps in completin Read more

Aim Perform the meshing the turbocharger model using the ANSA. Cleaning the turbocharger part and Assign the PID\'S Do the surface and volume mesh of the turbocharger. Turbocharger A turbocharger, colloquially known as a turbo, is a turbine-driven forced i Read more

Aim Fluid Flow behavior when the throttle changes his position with time. Throttle Valve Throttle, Valve for regulation the provision of a fluid (as steam) to an engine, particularly the valve dominant the degree of&n Read more


Loading...

The End