Lecture 4: Geometry Modeling - ttu.eeinnomet.ttu.ee/martin/munich/DM15/DM-Intro_15.0_L04_Geometry... · 1 © 2013 ANSYS, Inc. February 7, 2014 ANSYS Confidential 15.0 Release Lecture

1 © 2013 ANSYS, Inc. February 7, 2014 ANSYS Confidential

15.0 Release

Lecture 4:

Geometry Modeling

Introduction to ANSYS DesignModeler


Overview

In this lecture we will learn about: • DesignModeler Concepts

• How to create a 3D geometry?

• How to modify/transform a geometry?

• Part Management

• Concepts in DM from meshing perspective


Preprocessing Workflow

Sketches and Planes

Geometry Import Options

3D Operations

Bi-Directional

CAD/ Neutral

Geometry Cleanup and Repair

Automatic

Cleanup

Simplification,

Mid-surface,

Fluid Extraction

Extrude, Revolve,

Sweep, etc

3D Operations

Booleans,

Decompose, etc.

Import/ Geometry Creation

Geometry Modifications

Meshing Solver

Meshing Methods

Hybrid Mesh: Tet,

Prisms, Pyramids

Hexa Dominant,

Sweep meshing

Global Mesh Settings

Local Mesh Settings

Sizing, Controls,

etc.

Assembly

Meshing


Body Types In DesignModeler

• Line body

– Has length and consists of points as lower entity

• Surface body

– Has surface area and consists of points & edges as lower entities

• Solid body

– Has volume and consists of points, edges & faces as lower entities

• Bodies are listed in the Tree Outline identified by default names and icons

Important DM Concepts

Surface body Line body Solid body


Body States – Active

• Active bodies merge automatically with bodies in contact or overlapping.

– By default, DM creates Active bodies. To avoid active bodies or parts to merge together, use Add Frozen wisely.

– Frozen

• Frozen bodies remain independent

• Why to use Frozen bodies?

– If Meshing requires bodies to be decomposed

– If Solver requires different boundary & continuum conditions to be applied to different areas of the model

• “Unfreeze” can be used to Selectively convert Frozen bodies to Active State

Important DM Concepts

Active State: Single body after two feature creation operations

Frozen State: Two bodies (one frozen) after two feature operations


Tools for creating new bodies or modifying existing bodies

– Used to create bodies

– Requires lower dimensioned geometry as base objects

– Result is a line/surface/solid body

– Applies blend/chamfer on edges/faces of existing bodies

– Used to modify existing bodies

– Results in modified or new bodies

– Quick creation of primitive shapes (without sketch)

3D Features


Extrude Details • Geometry

– Can be a valid Sketch, selected face or Named Selection

• Operation

– Allows Add Material, Cut Material, Imprint Faces, Slice Material, Add Frozen

• Direction Vector

– Default option is Normal

• Other options are Reversed, Both-Symmetric and Both-Asymmetric

• Plane axes, geometric edges and faces can be used to specify direction

• Extent Type

– Fixed, Through All, To Next, To Faces, To Surface

Extrude

Sketch

Preview of the operation

Resultant body

Extent - Fixed

Extent - To Next

Direction - Symmetric

Direction - Asymmetric


Options for Operation

• Add Material

– Creates new body and unites with existing active bodies in contact or overlap

• Add Frozen:

– An independent body is created, with separate faces and edges

• Cut Material:

– Create holes or modify existing bodies by removing material

• Imprint Faces:

– Imprints the sketch on the faces of existing body. This only works for Active bodies

• Slice Material:

– Slice out resultant body from the existing Frozen body Add Material Add Frozen Cut Material Imprint Faces Slice Material

Sketch


Sweep Sweep Details • Selected profile is swept along selected path to

create bodies

• Profile

– Profile could be any sketch or entity to be swept

• Path

– Path could be a sketch or edge (open or closed)

• Alignment

– Path Tangent OR Global Axes

Profile

Path

Alignment - Path Tangent

Alignment - Global Axes

Swept Model


Skin/Loft Details • Takes a series of profiles and creates a body

fitting through them

– All profiles must have the same number of edges

Skin/Loft Feature

Multiple sketches


Thin Surface Details • Creates Thin Solid or Shell (Surface)

– Creation based on Selection Type; Faces to Keep/Faces to Remove/Bodies Only

– Faces to Keep: Selected faces used to form the thin solid or surface

– Faces to Remove: Unselected faces used

– Bodies Only: All faces used

– Specification of zero thickness will create a surface body (can specify offset)

– Direction for generation of thickness can be inward, outward or both (midplane)

Thin/Surface

Inward Outward Midplane


Face Selection

Edge Selection

Fixed Radius Blend Details • Creates a blend of specified radius on

face/edges

Fixed Radius Blend


Pattern Details • Creates multiple copies of selected features

in selected direction(s)

• Types of Pattern

– Linear, Circular and Rectangular

• Select Geometry (A Feature or bodies)

• Specify Direction, Axis, Offset/Angle, Copies

Pattern


Body Transformation Tools • Contains 5 tools for transforming bodies

– Move

– Translate

– Rotate

– Mirror

– Scale

Body Tranformation


• Creates a mirror image body reflected in selected plane

– Used for creating a full model from partial model which is Symmetrical

• Set Mirror Plane

• Select body/bodies to be mirrored

• Original body deletion controlled by ‘Preserve Bodies’ option

• Example – Mirroring car body in the XY Plane preserving the original

Body Transformation: Mirror

XY Plane


• Moves and aligns selected bodies

• Select body or bodies

• Select option to Preserve Bodies

• Set Source and Destination Planes

• Example – Aligning two bodies using corresponding source and destination planes on each body respectively

Body Operation: Move


Scale up : 2x

• Scale selected body or bodies

• Select body or bodies

• Set Scaling origin

– World Origin : Global coordinate origin

– Body Centroids: Centroid of the bodies selected

– Point: Selected Point

• Option to for Uniform or Non-uniform Scaling

Body Operation: Scale


Body Operation Tools • Contains 6 tools for manipulating bodies

• Options vary depending on whether the bodies are Active or Frozen

• Cut Material is not available if all bodies are Frozen

Body Operation


• To Slice out one body from the another body

Body Operation: Slice Material


Tool Bodies

Intersect all bodies Union of all intersections Union of all intersections preserving input bodies

Unite, Subtract and Intersect • Unite: Merges two or more bodies

• Subtract: Target Body subtract Tool Body

• Intersection:

– Union of All Intersections: Regions shared by two or more Tool Bodies

– Intersection of All Bodies: Regions shared by all Tool Bodies

Boolean

21 © 2013 ANSYS, Inc. February 7, 2014 ANSYS Confidential Slice Off Faces

Slice Options • Slice By Plane

– Model is sliced by selected plane

• Slice Off Faces

– Selected faces are sliced off and separate bodies are created from them

• Slice Off Edges

– Selected edges are sliced off and separate bodies are created from them

• Slice by Surface

– Selected surface is used as a slicing tool to slice

• Slice by Edge Loop

– Selected edge loop is used as a slicing tool

‘Slice’ Operation under ‘Create’


Suppressed

Suppressing Bodies

• Behaviour of Suppressed Body

– Will not be exported or transferred to other Workbench modules

– Not visible in Graphics view

– Identified by cross sign in Tree Outline

• How to Suppress or Unsuppress?

– Select the body to be suppressed, right click and select “Suppress Body”

– Select the body/bodies to be unsuppressed, right click and select “Unsuppress Body”

• Please note: Suppressing & unsuppressing bodies may change some features in tree, wherever they were used.

Suppression


Hiding Geometry

• Behaviour of Hidden Bodies

– In Tree Outline, Hidden body is identified by transparent “tick-mark” sign

– Hidden bodies are transferred to other Workbench modules and can also be exported

• Useful when working with complex models

• How to Hide or Unhide?

– Select the body or face to hide, right click and select “Hide Body” OR Press F9

– Right click “Show Body” to restore view

Visibility

Hidden


What are Named Selections?

• Any number of entities grouped together under one name

• These can be used to:

– Group Entities together for display purposes

– Define boundary conditions

– Apply Mesh Settings

– Define Meshing Order

• Can be created using one of two ways

– Select an entity or a group of entities, click RMB, select ‘Named Selection’ from the context menu or…

– Select an entity or a group of entities, click on Tools menu and select ‘Named Selection’

• Named Selections can be assigned to groups points, lines, surfaces or solids.

Named Selections


Working with Parts

• By default, DM places each body into one part by itself

• Single-body parts : Individual parts are meshed separately

– Non-conformal mesh at interface

• Multi-body part : Two or more bodies in a single part

– Conformal mesh at interface if Shared Topology set to “Automatic”

• Bodies can be grouped into a part in 2 ways :

– Select bodies. Click RMB and select Form New Part

– Select bodies. Go to Tools Form New Part

Single and Multi-Body Parts

Single-body Parts Multi-body Parts

All bodies in a single part


• Case 1: In DM: 3 parts, 3 bodies consisting of 3 solids

• Result of transferring this geometry to Meshing

– Contains: 3 solids, 3 bodies

– Each solid is meshed independently

– Nodes are not shared and do not line-up

– No connection between the 3 mesh regions for fluid flow and/or heat transfer

– Contact pairs are automatically created between parts/bodies in ANSYS Mechanical to transfer loads


DM Mesh

DM

Mesher


• Case 2: In DM: 1 multi-body part, 3 bodies/solids

• Result of transferring this geometry for Meshing

– Contains: 1 multi-body part, 3 bodies/solids

– Each solid meshed independently but node connectivity among solids is preserved

– Contains internal face which can be used for Post Processing

– No contact pair is created in ANSYS Mechanical


DM Mesh

DM

Mesher


• Shared Topology can be completed manually using

• Uses of Shared Topology – For getting Conformal mesh

– Imprinting for Contacts or Interface definition

• Options – For generating a conformal mesh for a Multibody Part, Shared Topology

needs to be completed with “Automatic” setting

– If conformal mesh is not required between two bodies in Part, but imprints of faces of one body on other are required (for defining contacts in Mechanical or Interface in Fluent), Shared Topology needs to be completed with “Imprint” setting

– For non-conformal, non-imprinted mesh on a body, Shared Topology setting needs to be kept “None”

Shared Topology

Shared Topology can be set through its Form

OR Shared Topology can be set for individual Part manually


Custom Shared Topology

• This option allows users to Selectively keep some bodies disconnected within same Part

• For Example: T-Joint formed by Two plates Welded Together

• Objective: To Make mesh conformal between Weld and Both Plates, but mesh should be non-conformal between plates

Non-conformal

Here Weld 1

Plate 2

Weld 2

Plate 1


Custom Shared Topology: Steps

• Form a part with all four bodies and Keep Shared Topology “Automatic” for Part

• For One of the plates (blue one), keep Custom setting of Shared Topology to None

– This will keep plate disconnected with remaining bodies, even when in same Part

• Use Connect operation Post Shared Topology to connect this body to both welds

Geometry Connectivity after Shared Topology

Black line here shows disconnected faces

Non-conformal mesh between two plates Conformal everywhere else


Summary

What have we learnt in this session?

• Important Concepts in DM such as Body Types & Body States

• 3D modelling tools in DM

• Geometry Transformation tools

• Visibility, Suppression and Part Management

• Conformal Meshing and Shared Topology


Workshop 4.1 – Modeling

Documents

Lecture 4: Geometry Modeling - ttu.eeinnomet.ttu.ee/martin/munich/DM15/DM-Intro_15.0_L04_Geometry... · 1 © 2013 ANSYS, Inc. February 7, 2014 ANSYS Confidential 15.0 Release Lecture