Nastran in a Nutshell - CAEfatigue Limited · 2019-05-04 · NASTRAN Analysis Capabilities SOL 400...

MSC.Software Confidential

MSC.Nastran in a Nutshell


Orientation

•  What is my job? –  Stress –  Dynamics –  Loads –  Designer –  Structural Analyst –  Fatigue & Fracture

Product Development Specialist!


Orientation: What is my job?

•  For your given part/product you decide:

Does this product do what it is supposed to do?

–  Will it break? –  Will it flex too much? –  Will it hold together? –  Can I make it lighter/

stronger/ better?


Where does simulation fit in?

•  Performance Simulation: How will this part perform? –  Will it break? (stress) –  Will it flex too much? (deflections) –  Will it hold together? (loads) –  Can I make it lighter/stronger/better? (optimization)


Simulation Cans and Can’ts

•  Can'ts –  What are the stress levels" –  Answer “Will it break, yes or no?”"

–  How much your part moves"

–  Answer “Is this too much (y/n)?”"

–  What sort of loads are carried"

–  Answer “Will it hold together (y/n)?”"

–  How to make it lighter/stronger"

–  Answer “Is this the best?”"

Tools cannot make judgments"

•  Cans


What do I need simulation to do?

•  Fast, accurate analysis of expected performance •  Reliable information upon which to answer the

question:

“Did I make this product perform?”


Execution: How do I…

•  What do I need to do simulation?

Input (raw materials):"–  Geometry"–  Properties"–  Materials"–  Loads"–  Boundary Conditions"

Output (finished product):"–  Displacements"–  Stresses"–  Strains"–  Forces"–  Reactions"


Basic Theory of FEA

•  I can’t easily figure out how a complex piece of structure will behave under loading…

–  But I CAN figure out how a simple piece of structure will behave…


Basic Theory of FEA

–  Therefore if I put enough of these simple pieces together, I can figure out how a complex piece of structure will behave!!!


Typical path through FEA

Pre-/Post-

Solver

CAD"

Results"

Input Deck"


How an Analyst sees FEA (Past)

Solver

CAD"

Pre-/Post-"

Results"

Input Deck"


NASTRAN Analysis Capabilities

Linear Statics (SOL 101) 0D 1D 2D 3D elements Plane Stress Plane Strain Axisymmetric Composites Substructures Force Pressure Temperature Displacement Force Stress Strain



Normal Modes (SOL 103) Natural Frequency Calculation Response Spectra Analysis



Linear Buckling (SOL 105) Linear Instabilities Euler Buckling Lateral Buckling Bifurcation



Complex Eigenvalue (SOL 107/110) Unsymmetric Matrices Rotor Dynamics Acoustic Analysis Stability

1

2

3

C2K2

K1

m2

m1


NASTRAN Analysis Capabilities Frequency Response (SOL 108/111) compute structural response to steady-state oscillatory excitation.

rotating machinery unbalanced tires helicopter blades Shaker table simulation



Frequency Response (SOL 108/111) Random Analysis Launch Environment Earthquake Loading



Transient Response (SOL 109/112) Compute a response to a time-varying input {P(t)}

Acceleration Vs Time

• Car suspension going over a speed bump

• Aircraft landing event

• Drop test



Cyclic Symmetry Static (SOL 114) Normal Modes (SOL 115) Buckling (SOL 116) Frequency Response (SOL 118) Cyclic

27x

Symmetry



Nonlinear Static (SOL 106) Transient (SOL 129) Implicit (SOL 600)

F

u Displacement

Load

Nonlinear Behavior

Linear Behavior

u

F

σ

ε Strain

Nonlinear Behavior

Linear Behavior Stress

Yield Pt.

PLASTIC

F F



Aeroelastics Static (SOL 144) Flutter (SOL 145) Dynamic(SOL 146)

y Spanwise Distance"

Lift"Rigid Wing"

Flexible Wing"



Heat Transfer Conduction, Convection, Radiation, Advection Static (SOL 153) Transient (SOL 159)


NASTRAN Analysis Capabilities Optimization (SOL 200)

tinit toptim

Shapeinit Shapeopt

•  Sizing and shape optimization •  Automated model updates

•  Design variables : –  Material properties (E, nu, rho, etc…) –  Element properties (I, J, Area, t, etc…) –  Connectivity properties (orientation,

mass, etc…) –  Grid locations (shape optimization)

•  Design constraints and responses : –  Stress limit –  Frequency –  Displacement

•  Objective : –  Minimize weight –  Maximize payload –  Minimize Error Function (test/

analysis)

October 7, 2012 This document is the property of MSC.Software : it can not be copied or given to a 3rd party without MSC.Software written agreement .

Page 23


Topology optimization

After smoothing

Optimization progression

•  Engine mount example

73K Grids 63K Solids 14 Subcases

Objective: Min Compliance Constraint: Fraction Mass Manufacturing: Casting Constraint


Page 24


Topometry optimization Optimized Thickness Distribution

Topography optimization

Conventional Design Topography Design

•  Free sizing optimization

•  Re-resizing on each element individually and produce a design material distribution over a design region


Page 25


26

NASTRAN Analysis Capabilities SOL 400

Large RB Kinematics

SOL 129 NL Trans

SOL 400 Implicit

NonLinear

Marc Components

SOL 153 Static Heat

SOL 106 NL Statics

SOL 159 Trans Heat


27

What is SOL 400

•  Pre-stress, transient event, steady-state residual •  Multiple, independent loadcases in 1 run

–  Use general 3-D contact capability •  Solid-to-solid, surface-to-surface, edge-to-edge

–  Go beyond small-strain element limitations •  Large strain elements / materials (shells, solids) •  CQUADR / CTRIAR nonlinear capabilities

• Advanced Integrated Nonlinear

•  MD Architecture enabled •  Utilize "native" Nastran

elements •  No translation required

•  Combine static & transient in one analysis


28

What could you do if you…

•  Model bolted / riveted joints instead of assuming them?

•  Make assemblies with dis-similar meshes? •  Could use these assemblies (all) linear analysis?


29

Contact in Linear & Nonlinear Solutions

•  MD Architecture enabled •  Marc contact “service”

–  General multi-body 2D & 3D contact

–  Deformable & rigid bodies –  Touching & Glued contact –  Contact with friction

•  Glued Contact for Dissimilar meshes

–  Faster model building –  Reduced “synchronization” effort –  Frees meshing specialists to work

on difficult problems

•  Full contact (statics)

•  Glued contact (all linear solns)


NASTRAN Analysis Capabilities SOL 700

•  SOL700 •  Glued and touching contact

•  Material plasticity, strain rate dependency, etc

•  Transient dynamic solution

07/10/2012

e.g. Heavy falling object


Bulk Data

Case Control Exec FMS

NASTRAN

GRID ID CP X1 X2 X3 CD

07/10/2012 31

Input (raw materials):"–  Geometry"–  Properties"–  Materials"–  Loads"–  Boundary Conditions"

Output (finished product):"–  Displacements"–  Stresses"–  Strains"–  Forces"–  Reactions"

Thank You !


07/10/2012 32

Bulk Data

Case Control Exec FMS

NASTRAN

GRID ID CP X1 X2 X3 CD

Date post:	10-Mar-2020
Category:	Documents
Upload:	others
View:	3 times
Download:	1 times

Nastran in a Nutshell - CAEfatigue Limited · 2019-05-04 · NASTRAN Analysis Capabilities SOL 400...

Documents