2. Zone-Based Process Activities - oss.jishulink.comoss.jishulink.com/upload/201603/1458999145500_Lesson_2_Zone-Based... · The Laminate Modeler dialog box is the main interface you

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© 2013. Siemens Product Lifecycle Management Software Inc. All rights reserved

Siemens PLM Software

1. Introduction to Laminate Composite Simulation

2. Zone-Based Process

3. Ply-Based Process

4. Modeling 3D Laminates

5. Materials and Micromechanics

6. Solution and Post-Processing

7. Laminate Theory

8. Laminate Failure Analysis

9. Laminate Dynamic Simulation

10. Laminate Optimization

Activities:

• Zone-based process on a

motorcycle mud guard

• Adding a reinforcement using

zone-based modeling

Lesson 2

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Overview of the zone-based process

Step 1: Create your mesh using shell or solid elements.

Step 2: Set the material orientation.

Step 3: On the mesh collector, create a laminate physical property by:

• Creating plies and stacking them in order to achieve desired properties.

• Selecting or creating the materials best suited to your application

Step 4: Validate your laminate.

Step 5: (Optional) Optimize your laminate.

Step 6: (Optional ) Create zones.

Step 7: (Optional) Inflate your laminate.

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Mesh creation for zone-based process Create 2D and/or 3D meshes using:

• 3D Swept Mesh

• 2D Mesh

• 2D Mapped Mesh

• 2D Dependent Mesh

• Commands on the Element Operations toolbar

• The resulting meshes are not associated to geometry

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Element types that support laminate physical properties

Note

1. NX Nastran only

Solver 2D Elements 3D Elements

NX & MSC

Nastran

CQUAD4, QUADR, CQUAD8, CTRIA3, CTRIAR, CTRIA6

CHEXA1,

CPENTA1

ANSYS SHELL91, SHELL99, SHELL181, SHELL281

SOLID185, SOLID186, SOLID191, SOLSH190

ABAQUS S3, S3R, S4, S4R, S4R5, S8R, S8R5, STRI3, STRI65

C3D8, C3D20, SC6R, SC8R

LS-DYNA ELEMENT_SHELL ELEMENT_TSHELL

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Material orientation By setting the material orientation, you define the laminate coordinate system that is consistent across the mesh. You may need to consider creating different meshes, or mesh collectors, in order to define different material coordinate directions. The material orientation is set in the Mesh Associated Data dialog box that you select by right-clicking on the Mesh nodes for the following solvers:.

•

•

•

•

NX Nastran

MSC Nastran

ANSYS

LS-DYNA

• For Abaqus, the material orientation can also be set in the Solver Properties group of the Laminate Modeler dialog box.

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Material orientation You can optionally define material orientation at the element level using Element Associated Data. Element Associated Data overrides Mesh Associated Data when the following check box is set in the Mesh Associated Data dialog box

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The Laminate Modeler dialog box is the main interface you use to create or modify

your Laminate physical property. You can access the Laminate Modeler dialog box

in one of the following ways:

• In the Laminates tab, click Laminate Physical Property

• Choose Insert → Laminate → Physical Property.

• In the Simulation Navigator:

1. Right-click a 2D collector node and choose Edit.

2. In the Mesh Collector dialog box, set the Type list to Laminate.

3. Click Create Physical

Laminate Modeler

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Laminate Modeler groups – Solver Properties

Lets you define solver-specific

properties and options.

This dialog changes according

to the fem’s solver

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Laminate Modeler groups – Laminate Properties

Lets you define Laminate-specific properties

and options.

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Laminate Modeler groups – Validation

Assess your laminate’s stiffness and strength

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Laminate Modeler groups – Ply Layup and Sketcher

Lets you create plies and ply groups and define a ply stacking sequence

Lets you view the laminate

Direction of the shell element normal

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Laminate Modeler groups – Optimization

Optimize the fundamental properties of your laminate using

a genetic algorithm

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Laminate Modeler groups – User-Defined Failure

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Stacking Recipe

• Specifies a predefined stacking sequence which operates on the plies in the

Ply Layup group.

Reference Plane Location

• Specifies the Z location of the reference plane relative to the layup.

Reference Temperature

• Is used to compute temperature-dependent material properties for laminate

validation.

• It is also exported to the NASTRAN PCOMP, PCOMPG, PCOMPS, and

PSHELL cards.

Defining laminate properties

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Ply failure theory

• Select a failure theory to compute the following ply failure metrics:

• Failure index

• Strength ratio

• Margin of safety

• The selected theory is used by NXLC Validation, Optimization, Advanced

Post Reporting as well as by NX and MSC Nastran.

• For the Laminate physical property, you can define a single ply failure theory

for all plies.

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Interlaminar failure can be computed using different stress limits:

When you select Use Material Allowables, NX Laminate Composites uses the SS13 and SS23 limits defined in an NX or ply material. When you select Use Laminate Allowables, NX Laminate Composites uses the Shear Stress for Bonding defined in the Laminate Properties group.

All plies have the same

interlaminar strength

Plies can have different interlaminar strengths

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Stacking recipe The stacking recipe operates on the ply list in the Ply Layup group, to create the desired laminate. This laminate is visible in the Ply Sketcher group.

•

•

•

•

•

Regular — identical to the ply list.

Symmetric — symmetric with even number of plies.

Symmetric with Core — symmetric with odd number of plies. The odd ply is

the central core.

Repeated — two copies of the plies in the ply list.

Repeated with Core — similar to the Repeated option, except that the top ply in the ply list is the core and is not repeated.

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Stacking recipe

Ply list Symmetric Repeated

Regular Symmetric with Core Repeated with Core

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The layup can be moved up and down with respect to the reference plane.

Reference plane location

Top

Middle

zbottom = - T = - 0.6 ztop = 0

zbottom

ztop

= - T/2 = - 0.3 = T/2 = 0.3

Bottom

zbottom = 0 ztop = T = 0.6

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User defined reference plane location

• When you select Specify from the Reference Plane Location list, you must

specify the Bottom Fiber Distance value.

• The bottom fiber distance is the distance between the reference plane

and the bottom of the bottom ply.

Specify Bottom Fiber Distance = - 0.1

zbottom = - 0.1 ztop = 0.5

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Using the shell’s outward normal (1) as the positive direction:

• Bottom fiber distance is negative (2) if the bottom of the laminate is in the negative direction from the reference plane.

• Bottom fiber distance is positive (3) if the bottom of the laminate is in the positive

direction from the reference plane.

User defined reference plane location

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Relationship between shell mesh and reference plane The shell offset displaces the reference plane from the node locations. Laminates with zero shell offset (1)

Laminates with nonzero

shell offset (2)

Midplane reference plane User specified reference plane

The plus sign, , indicates the plane of nodes.

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Relationship between shell mesh and reference plane Defining the shell offset The shell offset is defined in the Mesh Associated Data dialog box for the following solvers:

•

•

•

NX Nastran

MSC Nastran

LS-DYNA

For ANSYS, you can define a SECOFFSET in the Solver Properties group of the Laminate Modeler dialog box, for SHELL181 and SHELL 281 element types. For Abaqus, the offset is defined in the Solver Properties group of the Laminate Modeler dialog box.

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Stacking Sequence and Element Normal Direction It is important that the 2D element normals be consistently oriented as intended. Validation tools include:

From the Checks and Information group

of the Home tab, select Element Normals.

The normals will display as vectors, and

you can modify the normals of selected

elements

From the Top Border bar, select

Backface Culling. When the normals are

pointing in your direction, the element

colors are visible, otherwise the color is

invisible

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Defining plies and a stacking sequence

You create plies and define the stacking sequence using the following methods:

•

•

•

By creating new plies and ply groups, copying them, and moving them.

Importing from a spreadsheet or a CSV file.

Using the standard shorthand lamination format.

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Ply properties

Plies have the following properties:

• Ply ID. The ID is automatically assigned, however you can overwrite it.

• Material. A material must be selected.

• Thickness. A thickness must be defined.

• Orientation angle

• Color

• Description

• Solid Property: Layered or homogeneous When you create plies for a Solid Laminate physical property, you can also

define ply and interlaminar failure theories for each ply.

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Ply properties

Material

• Valid materials are any isotropic or orthotropic materials defined in the NX

material library or defined:

• As a new NX material.

• As an NXLC ply material in the Ply Material dialog box.

Ply orientation

• The ply orientation angle defines how each ply is oriented when it is stacked in a

layup.

• When the angle is 0, the ply coordinate system aligns with the material

coordinate system.

Solid Property

• When the laminate is inflated, this defines if the ply(ies) point to:

• A layered physical property.

• A homogeneous physical property.

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Commands to create a stacking sequence from scratch You create desired stacking sequence using any combination of the following commands:

• •

Create New Ply Copy and Paste family

and Move Selected Ply Down • •

Move Selected Ply Up Delete Ply

• Group Selected Plies , Ungroup Selected Ply Group , and Unlink

Selected Ply Group

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Ply groups

• You can create logically linked ply groups in order to efficiently create and

subsequently modify complex layups.

• A group can be a child, a parent, or both.

• Child groups are linked to parent groups as follows:

• The child group plies cannot be directly deleted or modified.

• When parent group plies are deleted or modified, the same changes are applied

to the child group plies.

• A ply cannot be added to a child group.

• When a ply is added to a parent group, it is automatically added to the child

groups according to the link rules.

• If a child is both a parent and a child, it cannot be directly modified, any

modification must be done to its parent.

• Groups may not be nested.

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Paste commands You can use the Copy and Paste family commands on a single ply, multiple plies, a single ply group, or multiple ply groups.

Paste Above or Paste Below Paste Repetition = 3

Paste Symmetric Above

Paste Symmetric Below

Paste Anti-symmetric Above

Paste Anti-symmetric

Below

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Use the Import Layup from Spreadsheet or Import Layup from CSV File

options to import your externally-defined layup into NX.

• The layup must be defined using 3 columns and as many rows as there are plies.

• The columns must contain, from left to right:

• Material name. This is the name of an existing NX material, or ply material.

• If the material name is not found in the FEM file, the layup is not

imported.

• Thickness, using the FEM units.

• Orientation angle, in degrees.

Note

• Importing a layup overwrites any existing layup

Using a spreadsheet or a CSV file to define a layup

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Using a spreadsheet to define a layup

Importing a layup from a spreadsheet is a 2-step process:

1. Copy your layup from a source spreadsheet and paste it into ‘Worksheet in

Layup Import – fem’ that was opened by NXLC.

2. Close the ‘Worksheet in Layup Import – fem’ spreadsheet or Excel.

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Defining a layup using the lamination shorthand format

Use the Import Layup Using Shorthand Format option to quickly define a layup containing plies with identical thickness and material.

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Defining a layup using the lamination shorthand format

The shorthand notation has the following conventions:

• A ply layup is contained inside [] (square brackets).

• Ply angles are separated by / (forward slash).

• Ply groups are contained inside () (parentheses).

• Symmetry is indicated by the suffix _s (underscore and s).

• For a symmetric layup, the suffix is placed after the square brackets.

• For a symmetric group, the suffix is placed after the parentheses.

• The core ply is indicated by ‘ (apostrophe)

• A repeated layup, group, or ply is indicated by _# (underscore and number sign)

where # indicates the number of repetitions.

• + (plus) and – (minus) in front of a number indicate the positive and negative

angles.

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Activity: Zone-based process on a motorcycle mud guard

The purpose of this activity is to introduce you to zone-based modeling

• Mesh half of the mud guard using shell elements.

• Create a 4 ply laminate using a

symmetric stacking recipe.

Notice how the material

orientations diverge at the

location show on the right,

where the shell normals nearly

align with the absolute X axis.

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Activity: Reinforcing part of the mud guard using zone-based process

The purpose of this activity is to show how the addition of a reinforcement

patch requires the creation of a new 2D mesh

• Use SHIFT-select to remove a face from the original 2D mesh

• Create a new mesh where the reinforcement will be applied

• Copy and modify the existing laminate

physical property.

• Assign the new laminate to the

collector with the 2D mesh of the

reinforced part.

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Exporting laminates to Fibersim

You can export laminate data to Fibersim PDI format.

• This format is used by the ACEE module in Fibersim to create zones, from which ply

definitions and transitions can eventually be created.

• To access the command, Choose Insert → Laminate → Export to FiberSim.

• Select which laminate physical properties you wish to export.

• Each 2D collector referencing the selected property (ies) will become a zone.

• The PDI file is an Excel file that contains:

• Zone definitions

• Laminate definitions

• Materials

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Review questions

1.

2.

3.

True/False. You specify the stacking recipe in the Solver Properties group of the Laminate Modeler dialog box.

True/False. When you create a new ply, you must define, at least, its

thickness and its material.

Yes/No. Can you modify a child ply group?

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Answers to review questions

1. True/False. You specify the stacking recipe in the Solver Properties group of the Laminate Modeler dialog box.

• False. You specify the stacking recipe in the Laminate Properties group of the Laminate Modeler dialog box.

2. True/False. When you create a new ply, you must define, at least, its thickness and its material.

• True. When you create a new ply, you must always define a material and a thickness.

3. Yes/No. Can you modify a child ply group?

• No. You create child groups from parent groups. When you want to modify a child group, you must unlink it or modify its parent group.

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2. Zone-Based Process Activities - oss.jishulink.comoss.jishulink.com/upload/201603/1458999145500_Lesson_2_Zone-Based... · The Laminate Modeler dialog box is the main interface you