Nonlinear Structural Analysis ME 24-688 Introduction to CAD/CAE - - PowerPoint PPT Presentation

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Nonlinear Structural Analysis ME 24-688 Introduction to CAD/CAE - - PowerPoint PPT Presentation

Oct 28, 2023 127 likes •560 views

Week 10 - Lecture Nonlinear Structural Analysis ME 24-688 Introduction to CAD/CAE Tools Product Lifecycle Week 10 Portfolio Conceptual Product Requirements Management Design Engineering Manufacturing Engineering Simulation &

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ME 24-688 Introduction to CAD/CAE Tools

Week 10 - Lecture Nonlinear Structural Analysis

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ME 24-688 Introduction to CAD/CAE Tools

Product Lifecycle – Week 10

Requirements Portfolio Management Conceptual Design Product Engineering Manufacturing Engineering Simulation & Validation Build & Produce Test & Quality Sales & Distribution Maintenance & Repair Disposal & Recycling

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Goals of Simulation

  • Validate Designs
  • Predict Product Performance
  • Optimize Designs
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Replicate the Physical World

The more closely a simulation conforms to what happens in the physical world, the more value it has to offer.

– Model Geometry – Analysis Type – Materials – Boundary Conditions – Loading Conditions

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Materials

  • The available material selection

is vast and changes everyday.

  • The material properties and

material model determine the behavior under operating conditions.

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Force Estimation Methods

  • Experience

– Engineers reply on past experience from similar projects to estimate forces.

  • Rigid-Body Dynamics

– Leverage the 3D design data to perform a motion simulation using rigid bodies to gain insights into force values.

  • Physical Experimentation

– Experiment with prototypes or past products to obtain accurate force values.

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Linear vs. Nonlinear Analysis

  • Linear

– Structure returns to original form – No changes in loading direction or magnitude – Material properties do not change – Small deformation and strain

  • Nonlinear

– Geometry changes resulting in stiffness change – Material deformation that may not return to

  • riginal form

– Supports changes in load direction and constraint locations – Support of nonlinear load curves

Focus for this week

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Nonlinear Analysis

  • Design Engineer Belief

– Too Complicated – Time Consuming – Specialized software packages

  • Reality

– Nonlinearities are common. – Advances in FEA Software – Advances in Computing Hardware

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Types of Nonlinearity

  • Nonlinear Material

– Materials that do not have a complete linear stress strain curve as seen in plastic and rubber materials for example.

  • Nonlinear Geometry

– The changing shape of a model when large deformations exists provide nonlinear changes in the components stiffness.

  • Nonlinear Boundary Condition

– Boundary conditions that involve components in contact with one another often produce disproportionate changes in deformation.

  • Nonlinear Loading Condition

– Loading changes over time.

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Materials Types

Stress = Strain =

Soft and Tough Change in Length Original Length

Area Force

Hard and Brittle Hard and Strong Hard and Tough

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Elastic Region Plastic Region

Polymeric Material Example

Stress = Strain =

Failure Change in Length Original Length

Area Force

Proportional Limit Yield Limit Young’s Modulus

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Nonlinear Boundary Condition

  • Component contacts produce stresses and

friction that result in disproportionate changes in deformation.

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Nonlinear Geometry

  • Changing shape triggers nonlinear changes

in stiffness of the part model.

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Event Simulation

  • Event simulation allows for the entire event
  • f a condition not just a static solution.
  • In mechanical engineering the static case
  • ften does not dictate the design.
  • Designs must consider the worst-case

scenario which often occurs after loading.

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Event Simulation Example F

Linear static solution would have the entire load carried by vertical member.

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Event Simulation Example F

With an event simulation the horizontal members would carry some of the load.

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Nonlinear Example

  • Unbending and bending a paperclip back

into position has nonlinear material and geometry effects.

Residual Stresses Plastic Stresses

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Everyday Nonlinear Requirements

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Autodesk Simulation

Autodesk Simulation helps designers and engineers make decisions earlier and predict product performance.

– Linear and Nonlinear Static Stress – Fatigue Analysis – Linear Dynamic – Mechanical Event – Heat Transfer – CFD – Multiphysics

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Element Types

The following are some of the element types available in Autodesk Simulation

– Beam – Spring – Brick – Shell – Truss – Special (Actuator) – Special (Membrane) – Special (Slider)

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Load Curves

Load curves control the load value through a multiplier over a time period. Each specific load can follow a different load curve.

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Six Flags Theme Parks - Case Study

“Our primary concern is safety. Inventor and Autodesk Simulation allow us to study real-world loading scenarios so we can be sure we have appropriate safety factors in our designs.” Mike Neuzil Corporate Engineer Six Flags Theme Parks, Inc. United States

Challenge

Maintain and renovate hundreds of thrill rides with minimal downtime.

Results

  • New, in-house design of anti-

rollback mechanism to modernize a wooden roller coaster, the Texas Giant

  • Better collaboration with

fabricators through use of high-quality drawings and documentation

  • Improve quality by increasing

reliability of high-wear parts.

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Howden - Case Study

“Flexibility, adaptability and reliability are the key benefits that we enjoy with Autodesk Simulation products.” Laurent Tisserand Technical Director Howden France

Challenge

Reduce the time taken to produce tenders with technically and economically competitive proposals, while taking account of increasingly detailed customer requirements

Results

  • Substantial reduction in total

design time.

  • Faster response to customer

design requirements.

  • Simulation allows

investigation and validation of new design approaches.

  • Weight reduction through

design optimization brings reduced costs.

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Computer-Cluster Projects (CP10)

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Guided Lab Project 1

Guides instructions for completing a static stress linear simulation in Autodesk Simulation.

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Guided Lab Project 2

Guided instructions for completing a mechanical event nonlinear analysis in Autodesk Simulation.

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Guided Lab Project 3

Guided instructions for completing a snap fit nonlinear analysis on a medical device in Autodesk Simulation.

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Problem Set Assignment

Analyze the electrical switch snap fit mounting to determine force required and design quality.

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Demo Topics

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User Interface

Setup tab Stress Analysis browser Graphical display

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Mesh Panel and Settings

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Simulation Browser

Multiple simulations Analysis Type Constraints and Loads Part Element Type Element Definition Material Surfaces Contacts

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Assign Materials

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Assign Constraints

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Assign Loads

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Contacts

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Analysis Parameters

Duration Capture Rate Load Curves

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Selection Panel

Selection Shape Select Type Subentites of Selection

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Run Simulation

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Results User Interface

Results Contours tab Stress Analysis browser Legend Graphical display

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Results Contours / Results Inquire

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Graph Results