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    By Chris Smith

    Autodesk Inventor Stress Analysis. Dynamic Simulation or Nastran?  What’s the difference, and which one do I need?

    At some stage in our design process, we may need to verify that what we are designing is suitable for purpose. Is it strong enough? Will it last for its expected lifetime? Can I save weight without compromising functionality? These are some of the many questions we may find ourselves asking.

    Investing time and expense into a project only to see issues in the final stages or during use can be frustrating and costly, but Autodesk Inventor has several tools available to subscribers that can help find and eliminate potential issues, reduce overall costs, and test designs before any real-world manufacture or use.

    In this blog I will briefly explain some of the tools and functionality so that you can start to leverage the right option for your designs and processes.

    Dynamic Simulation – Dynamic Simulation is a tool installed out of the box (OOTB) with Inventor Professional. With Dynamic Simulation you can simulate real world interactions with models and assemblies to:

    Find reactionary forces from known inputs - If I apply force to the pedals on a bicycle for X seconds, what is the maximum torque on the rear sprocket?

    Defining the path an object/feature will take. – If I change gear from high to low, what path will the derailleur pivot points take?

    Finding maximum stress values in a cycle – Over a 5 second cycle to reach a speed of 18Km/h from known acceleration values, what is the highest stress value on the pedal arm?

    Design jacks or springs – From the known travel distance on the front fork suspension and the forces applied by the rider’s mass/activity, what spring force is required to operate smoothly but safely?

    And much more…

    Inventor Dynamic Simulation does not perform stress analysis but can be used as a precursor to Inventor stress and frame analysis. It is a great tool to verify that your design performs the way you expect and to refine your design before final stage commitments.

    Inventor Stress and Frame Analysis – conduct basic finite element analysis studies from static assemblies, thin bodies and frames, static pressure testing and modal (frequency) analysis.

    Inventor Stress and Frame Analysis has integration with Inventor Dynamic Simulation and Inventor Frame Generator giving users easy to use workflows to share information between work environments to create, verify, and update their designs. Inventor Stress and Frame Analysis also allows for some parametric integration allowing for some automation of design, based on design criteria, like safety factor, maximum allowable stress, or deflection.

    Inventor Nastran – More complex finite element analysis and simulation software with much more control over certain inputs like material properties, forces, and types of analysis. Requires a much more in depth understanding of FEA processes.

    Nastran for Autodesk Inventor gives the user much more control over the simulation and available inputs. You can also conduct fatigue over time, buckling analysis, thermal transfer, CFD and much more.

    Hopefully this quick explanation of the simulation and analysis tools that are available to Autodesk Inventor Professional users will help you decide on the right tool set for your circumstances.

    For further information please speak to us at customer.services@cadline.co.uk