Getting Quality Results with Your Simulation

Application Engineer, CSWE

Quest Integration

Brandon Adkins

Agenda

• SOLIDWORKS Simulation • Determining the Proper Toolset

• Common issues and experiences

• Setting up Mixed-Mesh studies

Why Simulation?

• Tools to help us design better products • Valuable insight

• Test many variables

• Make decisions quickly

• Avoid unnecessary prototypes • Get closer to ideal in shorter time

Simulation | Flow | Plastics

Linear Statics… Is it Enough? (True Story)

Company designed an adjustable bracket for the new Huffy basketball rim

– Ran linear statics…design checked out.

– Showed finished product to customer. Ran live test in front of customer and design failed.

– Re-designed and re-tested. Linear statics passed.

– Showed customer again. Ran live test in front of customer and design failed. Huffy went to another vendor.

– What Happened?

Company failed to do a buckling analysis (notice the webbing).

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Linear Statics… Is it Enough? (True Story)

Company designed a new garbage truck that can hold more trash

– Ran linear statics…design checked out.

– Went ahead and built two prototypes for testing.

– When the back gate lifted, a VERY loud pop occurred.

– What Happened?

Company failed to do a non-linear buckling analysis.

Def

lect

ion Nonlinear Buckling

Occurred @ 60%

Total Load

Force

Simulating multiple failure modes

• Start with Linear Static

• Include other methods on the same model • Industry or Product dependent

• Vibration

• Buckling

• Fatigue

• Thermal Stress

• Get us closer to predicting the best possible prototype

Common Issues and Experiences

• Meshing

• Contact Definition

• Simplification

• Solver type/ options

Meshing

• Solid (3D) • Bulky objects

• Shell (2D) • Sheet metal and thin parts

• Beam or Truss (2D) • Long extruded parts with constant cross section

Nodes and Elements

Shell

Draft High

Solid

Draft High

Beam

Choosing your Elements

• SOLID – Default for standard features (Extrude, Revolve, Etc.) • Can be converted to Shell or Beam from RMB menu

• SHELL – Default for Sheet Metal features • Time saving 2D element

• BEAM – Default for Weldment features • Time saving 2D element

Which mesh type will work best?

• Single type • Pros – easy to deal with contact

• Cons – calculation time can increase very quickly

• Mixed Mesh • Pros – can help decrease calculation time quickly

• Cons – can be more difficult to deal with contact

Compatible or Incompatible

• Compatible – Overlay nodes where parts faces coincide

• Incompatible – Parts may coincide, but mesh nodes do not overlay.

Compatible vs. Incompatible

• Global Contact Option

• Mesh Setting Option

Compatible vs. Incompatible

• When to use it…

• Compatible is more accurate for part interface regions • Can be difficult to align nodes with parts that are much different in size

• Incompatible can yield successful mesh • May not be as accurate in part interface regions

• Recommend using “Mortar” Bonding • RMB Study Name> Properties> Incompatible Bonding Options> “More Accurate”

Mesh refinement

• Element size will have an effect on accuracy of the results

• Consider areas of most importance • Feature detail

• Contact areas

• Areas of criticality in the design

• Global Refinement

• Local Refinement • Manual and automatic

Mesh Refinement

• Manual – • Specify areas of the design to

apply mesh elements of a different size • User defined area and size

• Takes time and consideration to setup

• Great way to account for what is most important for your analysis

• Automatic – • Let the solver calculate results

• Successive loops of mesh refinement. • Determined automatically based

on Material strain energy

Automatic Mesh Refinement

• Adaptive meshing • H- adaptive

• Local mesh size is decreased based on strain energy in material

• P- adaptive • Element order increase based on strain energy in material

• Currently supported for Solid Parts and Assemblies with Linear Static Solver

Automatic Mesh Refinement • RMB Study Name> Properties> Adaptive

• None (Default)

• H – adaptive

• P – adaptive

Adaptive Finite Element Analysis h-Adaptivity, p-Adaptivity

Refining the mesh (h-Adaptivity)

Changing the “order” of elements (p-Adaptivity)

1st order (Draft Quality)

2nd order (High Quality)

… 5th order

Contact Definition

• Model is unstable error?

• Majority of cases have to do with contact definition

• Items to consider • Number of parts in contact

• Mixed Mesh types

• Global vs. Component vs. Contact Set

How to Find the problems

• Contact visualization plot

• Find Under-constrained bodies

• Frequency Analysis (Pre 2016)

SOLIDWORKS Simulation Professional

Contact Definition

• Global works for initially touching faces

• Components with gaps can still be accounted for • Local contact

• Global contact with gap specification

Contacts

• Interference detection • Using coincidence as interference

• Contact Visualization plot • Simulation Professional 2014 and above

• Troubleshooting • Use methods above

• Combine with suppression of components

Simplification

• Adequate mesh required to capture model detail

• Too much detail can leave you waiting… for a very long time

• Analysis Preparation Command Manager (2016 - What’s New)

• Tools > Geometry Analysis.

• Suppress features

• Tools> Find/Modify> Simplify

• Mid-Surface

Solver Type definition

• FFEPlus (Iterative)

• Direct Sparse

• Intel Direct Sparse

• Large Problem Direct Sparse

FFEPlus (Iterative) • Typically meant for large mesh problems with simple definition of

contact. • Global Bonded

• Not recommended for use with local contacts.

Direct Sparse

• Recommended for use with problems using the following… • Dis-similar materials

• Local contact definition

• Can be more time consuming for large mesh problems

Large Problem Direct Sparse

• Best of both worlds!

• FFEPlus

• Direct Sparse

• Large Mesh Model with local contacts defined and/or dis-similar material definition.

Intel Direct Sparse

• Static, thermal, frequency, linear dynamic, and nonlinear studies.

• Leverage enhanced memory-allocation algorithms and multi-core processing capability

• Improves solution speeds for simulation problems that are solved in-core.

Solver Type definition

• It can be beneficial to choose your solver type

• Automatic option • Typically a good choice

Remote Solver capabilities

• New in SOLIDWORKS Simulation Premium 2017

• Install the “SOLIDWORKS Simulation Worker Agent”

• Activate computer as a worker agent • Does not require you to activate Simulation license on another computer

SOLIDWORKS Simulation

• Setting up Mixed-Mesh studies

Getting Quality Results

• Consider the options discussed • Meshing

• Contact Definition

• Simplification

• Solver type/ options

• Consider the toolset • Other failure modes

Getting Quality Results with Your Simulation

Application Engineer, CSWE

Quest Integration

Brandon Adkins

brandon@qintegration.com https://www.linkedin.com/in/adkinsbrandon

https://twitter.com/bkadkinss

Application Engineer, CSWE

Quest Integration

Brandon Adkins

Thank You!