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ANSYS Structural ANSYS Structural MechanicsMechanicsANSYS Structural ANSYS Structural MechanicsMechanics

© 2011 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary© 2010 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary

Steven VarnamSteven Varnam

ANSYS ANSYS UKUK

Steven VarnamSteven Varnam

ANSYS ANSYS UKUK

ANSYS Mechanical FEA Suite

• Founded in 1970, ANSYS have been

developing generic Mechanical FEA software

for 40 years

• Originally developed for the nuclear industry,

quality was paramount in its design, now

in accordance with ISO quality controls

© 2011 ANSYS, Inc. All rights reserved. 2 ANSYS, Inc. Proprietary

• ANSYS FEA has the broadest range of

capabilities in the market-place, with

technologies for:

– Linear & Nonlinear (geometric/material)

analyses

– Static, frequency-domain & time-domain

– 0-D to 3-D elements

– Isotropic, anistropic, layered materials

– ....

ANSYS Mechanical Solutions

ANSYS Mechanical solutions articulates the best in class CAE

products and technology for structural, thermal, acoustics


products and technology for structural, thermal, acoustics

and coupled physics analysis that offers a unique class of

integrated simulation solution for the entire product

development process …

Product Offering/Target Users

• Built upon robust technology offers a range of products with a clear upgrade path from designers to

analyst.

ANSYS

ANSYS

Mechanical

ANSYS

Multiphysics

Functionality/Price


ANSYS

Professional

PlanDrafting

CAD

Concept

Simulation

Virtual

Prototyping

Advanced

AnalysisEvaluate Production

ANSYS

DesignSpace

ANSYS

Structural

ANSYS

Mechanical

ANSYS

DesignSpace

Mid-RangeFront End High-End

ANSYS

Professional

ANSYS

Structural

Functionality/Price

Product/Technology Description

ANSYS

DesignSpace

ANSYS

Structural

ANSYS

Professional NLT

ANSYS

Mechanical

Linear Structural Linear Structural Linear Structural Linear Structural

Solver Technology


Linear Structural

Steady State Thermal

Linear Structural


Transient Thermal

Linear Dynamics

Linear Structural

Non-Linear Structural

Linear Dynamics

Nonlinear Dynamics

Linear Structural

Non-Linear Structural

Linear Dynamics

Nonlinear Dynamics


Transient Thermal

Acoustics

Direct Coupled

ANSYS

Professional NLS

Linear Structural


Nonlinear Structural

Linear Dynamics

Analysis Methods & Solvers

Elements Technology

Solid Elements

2D Quad/Tri

3D – Hexa/Tetra/Wedge/Pyramid

Layered Solids

Solid Shell

Shell Elements

Lower/Higher Order

Layered Shells


Beam Elements

Multi material beam analysis

Beam Cross Section Definition

Special Elements

Rebars/Reinforcements

Links/Pipes/Springs

Cohesive Zone

User Elements

Gaskets


Materials Modeling

Material Models

Isotropic/Orthotropic Elasticity

Hyperelasticity

Plasticity

Viscoelasticity

Viscoplasticity


Creep

Other Models

Cast Iron Plasticity

Drucker-Prager

Shape Memory Alloy

USERMAT

Gasket Material

Concrete

Gurson DamageGasket Material

Hyperelastic Material


Contact Analysis

• Node-Node; Node-Surface; Surface-Surface; Line-Line; Line-Surface

• Small and Large Sliding

• Lower and Higher order elements

• Pure Penalty; Augmented Lagrange; Pure Lagrange; MPC contact

• Semi-Automatic Contact Stiffness Update

• Multiphysics Contact; Rigid Contact


• Multiphysics Contact; Rigid Contact

• Friction Sliding (Small/Large Deformation)

• Shell/Beam Thickness Effects

• Contact Manager Wizard

• Automatic Assembly Contact


Explicit Analysis

• ANSYS Explicit Dynamics Products:o ANSYS Explicit STR, ANSYS LS-DYNA, ANSYS AUTODYN

• Short duration localized phenomena• Transient dynamic wave propagation

o Gases, Liquids, Solids and their Interaction (FSI)• Nonlinear

o Material behaviorStructural behavior


o Structural behavioro Contact/Interaction

• Extreme loadings• Extreme deformations

o Large strains & strain rateso Material failure

Solutions for the Nuclear Power Industry

Containment

Reactor Pressure Vessels

Fuel Assemblies

Passive Safety Systems

Generation IV Reactors

Waste Storage & Handling


Coolant Pumps

PressurizersSteam Generators

Containment

Challenges

– Determining accurate seismic loads and responses

– Providing accurate safety analyses to regulators

Benefits of CAE

Hoop stresses in

a containment

building with

retrofit hole


Benefits of CAE– Avoid over-designing by performing

accurate seismic analyses– Accident simulation when 1-D tools

are insufficient• Impact of accidents on structural

integrity• Fracture mechanics• Showing jet-strike survivability

Courtesy of CTC, Tokyo, Japan

And CAE Associates

Boeing 747 striking a 3m thick

reinforced concrete wall

Cutting into, then repairing a

Post-Stressed containment vessel

Ve

rtic

al S

tre

ss

Original

Reduced

Tendons

Repair and

ReTension


Ve

rtic

al S

tre

ss

Ho

op

Str

ess

Courtesy CAE Associates

Façade Response

• Structure considered is L shaped in

plan with vertical edges attached to an

existing structure.

• Façade about 50m wide by 50m high

with an 8m wide entrance lobby at


with an 8m wide entrance lobby at

ground level.

• Total structure mass approx 2200

tonnes

• Scenario considered was a 100kg

TNT charge detonated 20 m from the

centre of the façade at ground level.

Façade Response – Blast Analysis

• Detonation and initial stage of blast

wave propagation used a 1D model

extending 12m from the centre of the

charge.

• 3D model included a rigid


• 3D model included a rigid

representation of structure.

• Initial analysis stage with gravity and

damping to allow the structure to

reach equilibrium under self weight

• Pressure field files stored at 1ms

intervals for application to structure

Façade Response – Blast Analysis


Deflections x 25

Fuel Assemblies

Deformation of a

fuel rod spring


Benefits of CAE

– Reduce design time and physical prototypes through simulation

• Spring design

• Assembly seismic vibration analysis

• Fluid-structure interaction simulation

Geometry image courtesy of the Korean Atomic

Energy Research Institute

Reactor Pressure Vessels


ANSYS Workbench

• Being part of the ANSYS Workbench

infrastructure opens up several

enhancements in overall process for the

structural mechanics users

– Geometry


– Geometry

– Meshing

– Post-processing

– Reporting

– Process scripting & chaining

– Automatic Project updates

ANSYS Workbench


ANSYS Structural Mechanics

• Geometry

– Direct CAD Links

• Connect to real CAD models

and create true parametric

analysis


analysis

– Create analysis geometry

• Geometry clean-up

• Simplification

• Create Shell & Beam

geometry

– Work with imported files


• Preprocessing

• Materials

• Linear-Elastic

• Plastic

• Hyper-elastic

• Creep

• Soils, Concrete

• Damage models


• Damage models

• Meshing

• From fully automatic to highly controlled

• Loads

• Imported data fields

• Time dependant

• Complex systems

• Contact

• Model real assemblies

• Bonded, Frictionless & Frictional contact


• Solving

• ANSYS solver technology

evolving to keep pace

with PC developments

Multi-core


• Multi-core

• 32 & 64 bit

• Clusters

• GPU


• Postprocessing

• Stress, Strain, Creep,

Contact, Reactions

• Linearisation


• Images

• Tabular data �� Excel

• Movie files

• Automated report

generation


• ANSYS Structural analysis


DesignXplorer

• Start with a workbench defined process

– Use parameters in:

• CAD

• DesignModeler

• SpaceClaim

• Engineering data

• Preprocessor


• Preprocessor

• Postprocessor

• Derived parameters

– Define design envelope• Parameter limits

• Descrete/continuous

– Define goal• Near target

• Min/Max

• Trade offs

DesignXplorer

• DOE

– Select DOE type

– Custom + Sampling (OSF)

• Candidate designs

• Response surface


• Response surface

• Six Sigma analysis

– Manufacturing best/worst case

Design Assessment- Introduction

• What is Design Assessment?

– Enables the customer to define additional data that is associated with

their model and then perform custom post processing.

• Custom definition of input data, result definitions & solve + post scripts

– Without any customisation, it enables the combination of existing

solutions

• Static Structural


• Static Structural

• Flexible Dynamics (at a specific time)

– Predefined scripts will be supplied for Workbench integration the

BEAMST and FATJACK products.

Design Assessment- Capabilities at R13

• Can be linked with both static

structural and transient analyses (at a

specific time)

• Solution Combinations

• User-defined Python scripts can be

written/run

• API for use with Python scripts


• API for use with Python scripts

– Able to access: Geometry & Mesh,

Solution Combination data, Attribute

group data, Results selection data

• Custom data variables with Solution

Combinations

• New Attribute Groups for the application of

user variables to the model.

• New Results type to display the results of

the custom post process.

Joint Unitary

Check for

BEAMCHECK

Spectrum AnalysisSpectrum AnalysisSpectrum AnalysisSpectrum Analysis


Spectrum analysis

Deterministic:

• Response Spectrum

• Single-Point Response Spectrum

• Multi-Point Response Spectrum


• Dynamic Design Analysis Method

Probabilistic:

• Random vibration

• Power Spectral Density (PSD)

Spectrum analysis


Spectrum analysis -

Static pre-stress


Spectrum analysis –

Modal analysis


Linear Dynamics

New SNODE Solver for Modal Analysis

� Splits FE matrix in to smaller pieces –

SuperNodes

� Solves reduced eigenvalue problem

� Transforms eigenvectors back to the

original FE domain

Advances in Solver Technology

Block Lanczos


Linear Dynamics

original FE domain

Benefits

� Ideal for > 3 mil. DOFs , >500 modes

� Non-iterative – i.e. will not fail to converge

� Does not miss modes

Applications

� Beam, shell or thin geometries

� Automotive, aerospace

� High frequency response analysis, etc.

0

20000

40000

60000

80000

100 1000 4000 8000

CPU Time

Number of Modes

Block Lanczos

Supernode

Single Xeon 3.4 GHz processor

►17+ hours reduced to ~1 hour

►7 TB of I/O reduced to <300 GB


Analysis settings



RS loading



Results



Random vibration (PSD) analysis


Spectrum analysis - Summary

Single-Point Response Spectrum (SPRS)

1. Build model

2. Obtain modal solution

Block Lancos (missing mass)

PCG Lancos (missing mass)

Supernode

3. Obtain spectrum solution

No. of modes to use

Spectrum disp, vel, accl,

Stiffness damping

Random vibration

Power Spectral Density

1. Build model

2. Obtain modal solution

Block Lancos (missing mass)

PCG Lancos (missing mass)

Supernode

3. Expand modes

request stresses if needed

4. Obtain spectrum solution


Stiffness damping

Constant damping ratio

Modal damping

4. Expand modes

5. Combine modes (max 10,000)

Square Root of Sum of Squares (SRSS)

Complete Quadratic Combination (CQC)

Double Sum (DSUM)

Grouping (GRP)

Naval Research Laboratory Sum (NRLSUM)

Rosenblueth (ROSE

6. Review results

Disp, forces, stresses (velocity or accel of)

Specify stresses if needed

Mass damping

Stiffness damping

Freq. Dependent damping ratio

Apply PSD excitation at desired nodes

5. Combine modes (max 10,000)

±1σ disp, stress,

6. Review results

Robust Design of a nuclear fuel rod and pin assembly

Courtesy of Korea Atomic Energy Research Institute

Robust Design of a nuclear fuel rod and pin assembly

Courtesy of Korea Atomic Energy Research Institute


Fuel pin on spring Courtesy of Korea

Atomic Energy Research Institute

• Hold rod firmly in place

• Avoid fretting wear and damage to fuel cladding


• Simulation

– Fuel rod depresses spring 0.3mm

– Calculate overall force, local contact pressures and stresses

– Parametric study highlighting the effect of spring width on fuel rod force






Input parameters

Response parameters


Response parameters

Displacement Stress Stress intensity

Contact

pressures

Reaction

force

• Response surfaces




Summary

• 20 years ago

– 1 geometry > meshed by hand > 1 set of material properties >

worst case loading > evaluate stresses > assign safety factor

make design decision



• Today

– Import CAD geometry > auto mesh > ±3σ variation in material

properties > ±3σ variation in load values > durability assessment


ansys structural mechanics uk/staticassets/ansy… · ansys structural mechanics © 2011 ansys,...

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