Why Design Engineers Need to Perform Their Own Simulations

Written By: Dave Martin

I’ve worked for Amazon, Boeing, and Lockheed Martin, and delivered training and consulting in analysis at dozens of companies. On many product development teams, data isn’t the only thing that’s siloed; people are too. Mechanical engineers tend to be split up between design, analysis, and manufacturing.

This process division of labor hurts product development and companies, but it doesn’t need to be this way. Here are three reasons design engineers need to learn and perform their own simulation.

Dave Martin quote: All engineers can and should perform their own simulations

Reason 1: It Takes Too Long To Wait for an Analyst

Engineers need to perform simulation in conjunction with the design process; it’s too late if they’re waiting until it’s done to find out there are fundamental problems with their approach.

Designers work on parts and assemblies, and when they are “done,” the models are often handed off to analysts who perform the simulation.

When the models don’t meet the requirements – as they invariably tend to do the first time through – they are thrown back over the wall for another design iteration. The design engineers often use blind trial and error and “SWAGs” (scientific wild something guesses) to improve the model. I’ll make it thicker. I’ll put in some bigger fillets. I’ll add some ribs. Maybe I’ll change to a stronger – and usually more expensive – material.

But what if engineers could perform their own initial structural and thermal simulations?  Small problems would never have to become big problems.  When I managed Creo at Amazon, I started engineers with Modal Analyses. The modes indicate how stiff an object is, at what frequencies it will resonate, and what mass contributes to each of the mode shapes.

Caption: A Chinook helicopter literally tears itself apart due to vibration during a ground resonance test

By performing analysis with design, significant design flaws can be identified and resolved early, before they are sent to an analyst. Plus, you avoid expensive physical prototypes that are destined to fail.

Reason 2: It Makes Them a Better Designer

By performing their own simulation and analysis, engineers gain a better understanding of how to design parts and assemblies.

For example, they learn how to place rounds to remove stresses at re-entrant corners and to remove non-structural mass to lighten parts. They design parts with load paths in mind, rather than removing material where the model needs strength.

When designing assemblies, they select the correct types and sizes of fasteners. Or they may opt for additive manufacturing techniques to provide continuous material and reduce the number of components.

Soon, they incorporate design for analysis techniques into the structure of their models, to facilitate downstream analysis. They select and group features for suppression and idealizations so that the model can be simplified to analyze faster.

Fan design with simulation underway

Reason 3: It Makes Them Better Communicators

Results don’t matter if an engineer can’t communicate the importance and repercussions of their findings. A lot of managers don’t understand concepts like stress, shear, buckling, vibration, and fatigue.

In my early days as a structural analyst, I would generate contour plots of my results, where colors would go from low values in blue to high values in red. Red was simply the peak value, but it might not necessarily be bad; the factor of safety could be high. But some managers would see red and call for a redesign. I would try to explain how the von Mises stress compared to the Ultimate Tensile Strength, but by then it was too late.

That taught me to use Failure Index plots, which normalize the stress values relative to the material properties. Then when reviewers see red, they know it’s bad, but when there’s no red, it’s safe.

Performing their own analyses teaches engineers these so-called “soft skills” like presentation and persuasion in order to convince those who might lack engineering knowledge to take the right path.

Simulation Is Faster and Easier Than Ever

Tools like Creo Simulation Live empower engineers because they are easy to learn and use while they design. Since it uses the computer’s graphics processor to perform analyses, results are delivered in almost real-time as the designer updates the model. By eliminating silos between engineering functions, the product development process becomes efficient and seamless. See the demo below, and then sign up to try it on your own models free.

 

An engineer demos Creo Simulation Live.

Get real-time feedback as you design. Try Creo Simulation Live free

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About the Author

Dave Martin

Dave Martin is a former Creo, Windchill, and Mathcad instructor and consultant. After leaving PTC, he was the Creo specialist for Amazon; and a mechanical engineer, Creo administrator, and Windchill administrator for Amazon Prime Air. He holds a degree in Mechanical Engineering from MIT and currently works as an avionics engineer for Blue Origin. 


Martin is the author of the books Design Intent in Creo Parametric and Top Down Design in Creo Parametric--both available at www.amazon.com. He can be reached at dmartin@creowindchill.com.