Predictive Engineering with Mathcad

Mathcad won’t tell you who’s going to win the next World Cup or World Series, but it can give you some valuable clues about the future of your newest mechanical design, clues that can potentially save you time and headaches in getting your product out the door.

Here are five ways you can look into the future with Mathcad:

During concept planning, early sizing or verification can save time by answering basic questions about form and fit. To build a refrigeration unit, for instance, you could use Mathcad to see if the piping fits within the refrigerator casing.

Similarly, a cell phone designer could check the basic fit of the printed circuit board, speaker, or microphone. Valuable here is Mathcad’s support (in Mathcad 15 and Mathcad Prime) for Design of Experiments, which lets you perform various “what-if” analyses using multiple independent variables.

For a requirements definition meeting with other engineers, marketing or business development people, a project manager, and maybe even a customer, you can use Mathcad as a scratchpad to explore alternatives that might come up in the meeting. Doing math on-the-fly lets you keep the spontaneity of the group alive.

Such methodologies of “requirements flowdown” can easily be performed in Mathcad, deriving lower level requirements through analysis and modeling, by using higher-level system- or market-driven requirements.  Capturing calculations in this manner helps in ongoing reviews, and in making sure the entire team progresses confidently on the same page.

In design modeling you start by looking for previous CAD parts or assemblies that can be reused, as well as any available standardized engineering  calculations – that is, existing analytical models within the organization, or proven best practices that can be re-used or referenced.

Say you’re building a shock absorber. You go to the calculations library and retrieve the current analytical model, perhaps along with any axle model or other CAD assemblies that make use of that shock absorber. When your CAD models are tightly coupled with the engineering calculations and assumptions that drive them, you might be able to see that the original shock absorber was intended for a light truck, and then later modified for an even lighter SUV.

You can use this information to see if you’re OK using that part, or if you should re-start a new design. The more detail you can see from the previous engineers’ calculations and analyses, the better your chances of making the right decision about your future model.

Finally, before turning the model over to manufacturing you can use Mathcad to check that the model meets manufacturing specifications - everything from tolerance analysis to safety and/or Six Sigma parameters.

Tolerance Analysis in Mathcad

As a prelude to analysis, you can use Mathcad for basic sizing and testing of top-level assumptions – and again, for some projects, its Design of Experiments capabilities can help greatly. This information helps you sharpen the focus of the problem that will be presented to the analysis application. You avoid wasting time on a misdirected analysis project, since a full FEA simulation can take several hours.

Finally, before turning the model over to manufacturing you can use Mathcad to check that the model meets manufacturing specifications – everything from tolerance analysis to safety and/or Six Sigma parameters. This lets you head off any potential conflicts before the model goes into production, where changes become exponentially more expensive to fix.

This is one of the many ways in which Mathcad can be used for requirements verification, ensuring that any derived lower-level requirements satisfy the higher-level requirements.  Requirements verification can certainly be performed through prototyping or subsystem construction, but can also be accomplished through proper modeling, and even combining Mathcad analyses with other simulation tools.

Requirements validation may come a little too late in the process to properly be called predictive engineering, but Mathcad also often helps answer one final, all-important question: “Did we build the right product?”

Can you add to these examples? Please do – let us know how Mathcad helps you predict the future of your design projects!

About Bettina Giemsa

I graduated from Ruhr University in Bochum, Germany, with a Master of Arts in American Studies, Japanese, Economics * Started my career in Marketing on the agency side, spending almost 3 years in media planning * Ran Marketing at ITEDO Software GmbH, Germany from 2001-2006 where I first got in touch with the CAD business * Became part of the PTC Marketing organization when ITEDO was acquired by PTC in October 2006 * Last, but not least, I am the mother of a 4-year-old, and sometimes wonder which is harder to cope with: a little girl with a temper or a busy workday…
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