AMTS-Composite Design 3

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Composite Design Section 3 of 3AMTS-SWP-0049-F-2011

AMTS STANDARD WORKSHOP PRACTICE_________________________________________

Composite design Section 3 of 3: Composite design andanalysis software

Reference Number:

AMTS-SWP-0049-F-2011

Date:

November 2011

Version:

Final


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Contents

1 Scope ............................................................................................................................ 22 Technical terms.............................................................................................................. 23 Primary references ......................................................................................................... 34 Interacting of Software ................................................................................................... 45 Comparison between Laminate software ....................................................................... 56 Considerations regarding composite software. ............................................................... 6

6.1 Model creation ........................................................................................................ 66.2 Material properties .................................................................................................. 76.3 Meshing .................................................................................................................. 76.4 General analysis ..................................................................................................... 76.5 Failure Analysis ...................................................................................................... 86.6 Design optimization ................................................................................................. 86.7 Manufacturing ......................................................................................................... 9

7 Links to various software ................................................................................................ 9


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1 Scope

A sophisticated analysis plays an important role in the development of aerospace structures.

It is required that many specialities are combined on an overall problem in any complexdesign structure. For each of these specialities the specific knowledge must be known bythe designer. [1]

This SWP is part 1 of three SWPs which covers the following information:

SWP 42: Composite design Section 1 of 3 - Composite definition- Composite classification- Basic terminology- Lamina Theory- Laminate Analysis Theory- Static strength life of composites

Theory- Beam Analysis theory

SWP 48: Composite design Section 2 of 3 - Fundamentals of Composite designdecisions

- Advantages / Disadvantages- General guidelines for composite

designs

SWP 49: Composite design Section 3 of 3 - Interacting of software- Comparison of various software tools

- Considerations in software- Links to various software

2 Technical terms

Laminate analysissoftware

Software tools for the design and analysis of composite materiallaminates of which the algorithms is based on the Classical

Laminate Theory.Classical LaminateTheory

An approach where the laminates are assumed to be of infinitelength and widths, i.e. edge effects are ignored. Plane stress stateis assumed and certain stress components are ignored.

Laminate A thin plate of infinite length and width, made up of one or moreorthotropic laminae bonded together, each of potentially differentthickness and material, and each with the principal stiffness axis (orFibres) at a user-defined orientation.


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3 Primary references

The main sources used for this document are indicated below. At the time of publication, theeditions indicated were valid. All standards are subject to revision, and parties to agreements

based on this document are encouraged to investigate the possibility of applying the mostrecent editions of the standards indicated below:

[1] LAP, 2010. LAP user manual for Laminate analysis Program version 4.x for

windows. Revision 5. Anaglyph

[2] LAP, 2010. Laminate analysis Program demonstration, Microsoft Power point.

Anaglyph.

[3] ESACOMP, 2010. Quick Start guide for EsaComp version 4.3.

[4] Waterman, P.J.1 May 2011. Options for Composites Analysis and Simulation. Find

your comfort zone with todays software tools.Desktop engineering.

[5] Waterman P.J. 2 March 2009. Composite Analysis: Making New Choices. An

engineering and design gide to choosing software for working with todays composite

materials. Desktop Engineering.


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4 Interacting of Software

When compared to traditional engineering materials, like steel, the material andmanufacturing costs of composites are high; therefore the superior performance of the end

product must be achieved by careful designing involving software. The flow chart in figure 1shows how Laminate Tools interacts with other engineering software applications. [4]

The two major different approaches in composite designing software is a CAD environmentor an ANALYSIS environment. Any finite element analysis tool, or FEA package, is notsufficient to design, manufacture or create decent composite models, it is only for analysing.[4]

The difference in the two approaches is as follow [4]:

Design works with very detailed, complete, producible design

Analysis work with simplified models made for analysis of buckling, delamination,noise or vibration.

Any application should be identified by its complexity as an guide to which approach shouldbe followed.

Figure 1: Typical Anaglyph Laminate tools composite analysis flow chart [4]


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5 Comparison between Laminate software

The following table explains the difference in composite software packages in categoriesfrom modelling to general and complex FE analysis[4]:

Table 1: Spectrum of composite software [4]

CATEGORY EXPLANATION COMPANY (PRODUCT)

LAMINATE ANALYSIS

Laminate analysis packages: Based onClassical Laminate Theory, these toolsallow you to define a flat laminate materialmade of an arbitrary stack of lamina, andcalculate stresses and material failure at agiven point under a given load.

Anaglyph (Laminate Analysis Program LAP),Componeering (ESAComp, ComPoLyX), Lindell

(The Laminator)

SUBSTRUCTUREANALYSIS

Substructure analysis: This type of softwarecalculates stresses and material failures insimple composite structures such as tubes,

beams and other straightforwardconfigurations.

Anaglyph (Component Design Analysis CoDA),Componeering (ESAComp)

MICROMECHANICALSTRUCTUREANALYSIS

Micromechanical structure analysis: Thisprocess creates detailed micromechanicalmodels of a composites structure tocalculate elastic and failure properties,particularly progressive failure. These toolsare often linked to, or integrated within,non-linear FEA solvers to predict failure.

e-Xstream Engineering (DIGIMAT), FireholeComposites (Helius:MCT, Prospector:

Composites and Helius: CompositePro), AlphaSTAR Corporation (ASC) (GENOA),

Componeering (ESAComp)

FINITE ELEMENTANALYSIS (FEA)

FEA: Most FEA packages allow users todefine laminated composite materials onshell elements. More advanced packagessupport laminated solid and beam

elements. A few even support ply-levelmodeling, where you can define theorientation of the material at each element.

ADINA, Altair (HyperWorks), ANSYS, Autodesk(Algor), COMSOL, Cranes Software (NISA),

LUSAS (LUSAS Plus Composite), MSC.Software,NEi Nastran, SAMTECH, Siemens PLM Software

(NX), SIMULIA (Abaqus/CAE), Strand7,Vanderplaats R&D (GENESIS)

FEA OPTIMIZATION

FEA optimization software: This softwareworks in conjunction with FEA tools andties into the manufacturing process bymodifying the composites layup onelements, using an optimization strategy toachieve the required structural response.

Collier Research Corp. (HyperSizer), ESI Group(SYSPLY), e-Xstream Engineering (DIGIMAT),Vanderplaats R&D (GENESIS), Componeering

(ESAComp)

FEA-BASEDINTERGRATED

DESIGN/ANALYSIS/

MANUFACTURE

FEA-based IntegratedDesign/Analysis/Manufacture: In an FEAenvironment, users can define a high-fidelity composites model by simulating the

manufacturing process of each ply, buildingup the stack model.

MSC.Software (Patran Laminate Modeler),Simulayt Composites Modeler for Abaqus/CAE(SIMULIA), Simulayt Composites Modeler for

Femap (Siemens PLM Software), VISTAGY with

ANSYS, Anaglyph (Laminate Tools for Nastranand ANSYS)

CAD-BASEDINTERGRATED

DESIGN/ANALYSIS/MANUFACTURE

CAD-based IntegratedDesign/Analysis/Manufacture: In a familiarCAD environment, these tools let usersdefine plies using boundary curves on anunderlying surface (rather than specifyingshell FEs).

Dassault Systmes (CATIA V5/V6 CompositesDesign) (with Partner Products: ESI Group

PAM-RTM for CATIA V5, SimulaytAdvancedFiber Modeler for CATIA V5/V6, Composites Linkfor CATIA V5/V6), VISTAGY (FiberSIM for NX,ANSYS, Pro/ENGINEER and CATIA V4/V5),

Simulayt (Composites Modeler for SolidWorks),Anaglyph (Laminate Tools for SolidWorks)


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6 Considerations regarding composite software.

The following list is questions and situations to consider when dealing with any compositedesign structure. The answers are applicable to durability and manufacturability. [5]

6.1 Model creation

Composite-based models for FEA incorporate the general defining of the geometry, materialproperties and meshing. The difference when working with non-isotropic materials is thatthe software lets you define the differing nuances of each layer. 3D-CAD and analysispackages do support this in general, but how the software approach it and the othersupporting additions need to be considered [5]:

Virtually unlimited number of possible layers

Different designs calls for different number of layers, some are only 5 layers andothers may require thousands. Restrictions in the modelling should not be aproblem for any composite software.

Import layer data

It is important to be able to import layer data such as stiffness and strength fromspreadsheets.

Easy insertion / deleting of layers

Layers should be able to be easily inserted or deleted and any point of the process.

Defining of fibre orientation angles

The software should be able to handle angles with respect to global axis, local axis,

normal to the shell surfaces and a plane defined by two intersecting planes, or along anarbitrary curve.

Mixing of composite and non-composite elements

It must be possible to mix elements such as beams, springs and shells made ofmetallic structures with the composite elements.

Glues and adhesives modelling between layers

It is preferred that the flues and adhesives are surface-based cohesive contact andnot just very thin layers.

Defining of cores

It should be possible to define layers as honeycombs or to be able to include rebar

material. Physical property updating

It should be possible for the design to have physical holes and updating ofthicknesses, angles and material properties should be easy. The modelling processshould also be able to correspond to different manufacturing processes like hand-layup, filament winding, compression moulding and infusion.


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6.2 Material properties

The applicable software should be able to define specific material properties. It should eitherhave its own database or it should be capable of importing material properties from

commercial services such as MatWeb and Matereality. The following questions should beasked regarding material properties [5]:

Does it allow unit-cell-based micro-material models? Can it also incorporatecontinuum material models? Can it handle a mix of elastic and inelasticmaterials?

Can you designate fibre packing as well as braided or woven configurations?

Can you introduce random variations in fibre orientation to allow formanufacturing realities?

Can you enter equivalent stiffnesss as a starting point, especially early in thedesign phase, and then replace those values on a layer-by-layer basis?

Does the software allow user-defined equations in the property matrix?

Is any necessary unit-conversion handled automatically?

6.3 Meshing

After the completion of the model there should be options for directing the meshing (FEdefinition) process. The two different approaches are solid elements or layered shellelements. Mostly analysts starts by modelling the structure as a layered shell element andthen switch to a detailed solid element mesh for the understanding of, for example, inter-laminar shear stresses. Such a change should be automatically extracted, especially fromthe mid-planes. [5]

6.4 General analysis

Both implicit and explicit solvers should be offered by the software, as well as macro- andmicro-mechanical analysis at the following levels [5]:

Global level: Structure Deflection, buckling, natural frequency

Ply/layer level: inter-laminar shear formations and stresses

Matrix level: detailed stress distribution within a single layer

Other important functions within general analysis of the software should include, if possible,[5]:

The same FEA model use for both implicit and explicit solutions.

Should be able to handle metal-matrix, ceramic-matrix and polymer-matrixcomposites

An option should be available to compute equivalent material properties in eitherthe pre-processor or the solver.

Material properties should be able to change in proportion of the geometry andshape.


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It should be able to account for heat transfer effects and solve simultaneously formulti-physics like conductivity, thermal and fluid structure interactions.

It should account for initial strains in the different composite layers, like pre-loaded layers during manufacturing.

Should be able to compute out-of-plane stress (Stress in the z-axis), inter-laminarshear and peel stresses. (In addition to the classical laminate theory in-planestresses and strains.)

All the mentioned properties will make visualization harder and thus more critical. Thefollowing display options should be available at orientated angles and normal layer-by-layer[5]:

Stress results for core, worst and specified lamina

Strain for composite elements (initial, mechanical and total)

Damage energy density

6.5 Failure Analysis

Damage modelling of composite structure is critical in the analysis software. The failuremodes of composite and laminate materials are subject to different failure modes than thosefound in single-material structures. Degradation of the performance is subjected to bothdelamination (Laminate based failure) and fibre/matrix breakdown (ply based failure) ondifferent levels of severity. For example, the outer layers can wrinkle, crimp or dimple and

damage of one layer can equate to failure of the entire part or not. [5]

BVID (Barely visible impact damage) investigation should be possible for the software withthe definition allowable damage tolerance and own macros. Simple values like maximumstrain and stress, quadratic Tsai-Wu, Hill, and Hoffman failure modes should be included.Some of the newer criteria will account for fibre/matrix failure separately using models likeHashin-Fabric, Hashin-Tape and Puck.[5]

Other properties that could be useful include [5]:

Crush simulation

Public-domain VCCT code for post processing and re-meshing of progressivecrack growth propagation between bonded surfaces.

Immediate or gradual stiffness reduction for matrix and fibres Damage addition at simulation

De-activation of simulate material removal/breaking

Fatigue analysis (rare capability on composite analysis)

6.6 Design optimization

Typically the composite material is optimized for the perfect strength to weight ratio. Thelarge number of variables, however, makes the optimization an important task and may leadto overall conservative designing. The following should be kept in mind:

Provision for interactive optimization capabilities to determine for a given loadenvironment the lightest weight combination of material systems and ply layups.


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Easy re-orientation of layers, stacking sequences or material type change tocompare behavioural differences.

Optimization of a complete structural entity such as wings or fuselages.

Handling of sandwich/ solid-laminate structures. Coupling with other solver software and pre/post-processors.

Tolerances in design parameters and variation of it.

Objective optimization like low vibration/multiple objectives.

6.7 Manufacturing

The simulations can provide insight to the model, but only theoretically and a real productmust still be manufactured. An interface between the analysis software and the various

manufacturing solution packages should be available. The some of the following termsshould be available; draping, taping, braiding, flat-patterns and ply drop-offs. The softwaremust also be able to help with incorporate non-geometric details such as glues, fasteners,coatings and sealants, and predict any expected shrinkage, thermal warping and spring-back. [5]

7 Links to various software

LAP: http://www.anaglyph.co.uk/LAP.htm

ESAComp: http://www.esacomp.com/overview/what-is-esacomp

PATRAN: http://www.mscsoftware.com/Products/CAE-Tools/Patran.aspx

NASTRAN: http://www.mscsoftware.com/

SOLIDWORKS:http://www.solidworks.com/sw/products/details.htm?partnerID=58&productID=833
http://www.anaglyph.co.uk/LAP.htmhttp://www.anaglyph.co.uk/LAP.htmhttp://www.esacomp.com/overview/what-is-esacomphttp://www.esacomp.com/overview/what-is-esacomphttp://www.mscsoftware.com/Products/CAE-Tools/Patran.aspxhttp://www.mscsoftware.com/Products/CAE-Tools/Patran.aspxhttp://www.mscsoftware.com/http://www.mscsoftware.com/http://www.solidworks.com/sw/products/details.htm?partnerID=58&productID=833http://www.solidworks.com/sw/products/details.htm?partnerID=58&productID=833http://www.solidworks.com/sw/products/details.htm?partnerID=58&productID=833http://www.solidworks.com/sw/products/details.htm?partnerID=58&productID=833http://www.solidworks.com/sw/products/details.htm?partnerID=58&productID=833http://www.solidworks.com/sw/products/details.htm?partnerID=58&productID=833http://www.mscsoftware.com/http://www.mscsoftware.com/Products/CAE-Tools/Patran.aspxhttp://www.esacomp.com/overview/what-is-esacomphttp://www.anaglyph.co.uk/LAP.htm

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