FEA Turns a Good One

By Caren D. Potter

KIC Holdings is a fast-growing, global operation that has averaged 50 percent growth per year for the past four years. The company leverages North American technology, design, and distribution with Chinese foundry and manufacturing expertise to provide a “just in time” supply of wheel end products such as hubs and brake drum assemblies for such trailer, axle, and suspension manufacturers as Hendrickson, Dana Corp., Hyundai Translead, Cheetah, and Lufkin Trailers.

Because a big part of the company’s growth strategy is its aggressive pricing strategy, KIC’s product development team must balance the demands of making products as light as possible while also delivering exceptional strength and durability. To meet these design challenges, KIC’s product development team has long relied on CAE technology.

KIC Holdings

> > UGS Corp.’s Femap with NX Nastran is used to perform a static analysis for rotary hub fatiguepredictions. The axle is loaded, and this load is transmitted through the bearing cups, hub, drum, and into the wheel simulator test plate. The axle creates a force couple through the bearings and into the hub. The moment from the force couple causes the hub to bend. The half symmetry cut allows the maximum bending stress to be observed.

“Commercial over-the-highway tractors and trailers generally have a million mile life target,” explains Joe Brotherton, director of product development at KIC. “Our wheel hubs are expected to last the life of the truck. Brake drums, although they are a service item, must meet federal performance standards and the durability expectations of our customers, typically 300,000 to 500,000 miles for over-the-highway trucks.”

For years, designers at KIC have been using FEA to help accomplish this. From its first FEA program, Pro/Mechanica, the company later migrated to MSC.Nastran for Windows. But when a local VAR demonstrated Femap with NX Nastran, the company decided to switch. According to Brotherton, this was a good decision.

Femap with NX Nastran was easy to get started, according to KIC. This was due in part to the software itself and in part to the support from the local UGS VAR, Predictive Engineering (Corvallis, OR). In contrast to MSC.Nastran, installing Femap with NX Nastran was a walk in the park.

Brotherton explains that MSC.Nastran was difficult to set up. “It took a week trading e-mails with MSC to do,” says Brotherton. “We had to do things like modify initialization files to address setup issues as well as to account for licensing. There was none of that with Femap with NX Nastran. The software was loaded quickly and ready to use.”

KIC Holdings

KIC Holdings

These KIC Holding screen shots of the pre-processing application of UGS Femap with NX Nastran show analysis results of a truck brake drum assembly. The left graphic is the inboard view while the right is the outboard view.

Predictive Engineering helped with the transition by demonstrating certain modeling procedures in Femap with NX Nastran. “Having a resource like ]Predictive Engineering] got us up to speed faster than buying software in a box,” Brotherton adds. “The ability to have a local reseller that is so eminently knowledgeable was definitely a selling point for Femap with NX Nastran.”

Brotherton also appreciated the information available from UGS on the Femap with NX Nastran website. “It has suggestions and you can get feedback so it has been a good resource for us,” he adds.

KIC uses Femap with NX Nastran to provide a virtual proving ground for testing parts. In the real world, physical testing is expensive and slow.

“For the cost of two individual brake drum tests, I can buy Femap with NX Nastran and do countless computer studies,” Brotherton says. “These studies give insight into the behavior of the parts that we produce. This allows us to meet our customers’ expectations for lighter weight products, cost reductions (lighter is cheaper), and improved performance. Our customers are engineers, and they look to FEA as part of the design verification.”

In KIC’s experience, one of the main differences between MSC.Nastran and Femap with NX Nastran has been the level of user-friendliness. “While MSC.Nastran ran on the Windows platform, it did not really take advantage of Windows functionality,” Brotherton says. “Femap with NX Nastran conforms to all the Windows conventions, so right from the start it’s more accessible. Because information is so readily available, and I was able to navigate through the program so intuitively, I learned it much faster than I learned MSC.Nastran.”

What Brotherton has found is that the user-friendliness of the new software invites its further use. “It’s the small things that make Femap with NX Nastran more user-friendly, and the ease of working with it makes you want to do more analysis,” he notes.

Since the upgrade to Femap with NX Nastran, KIC has done some analyses that it never attempted before. For example, Brotherton recently performed a nonlinear contact analysis involving bearing cones in a wheel drum. “When I tried to do a similar analysis before, I had to simplify it considerably,” Brotherton explains. “With Femap, I was able to create a more complex model that ran quickly and got good results.” The end result of the ability to create more complex models is a better ability to predict product performance and optimize weight.

Femap with NX Nastran offers functionality capable of handling demanding analysis problems. One important capability that Femap with NX Nastran provides is the ability to combine element types within a finite-element model. Some of KIC’s analysis models may contain imported solid models (usually in .sat format and then automatically meshed) as well as beam elements and plate elements that, for example, represent a wheel.

KIC Holdings

KIC Holdings

These KIC Holding screen shots of the post-processing application of UGS Femap with NX Nastran show analysis results of a truck brake drum assembly. The left image is the inboard view while the right is the outboard view.

“Now that we can combine all these elements, we can more accurately simulate mechanical systems,” says Brotherton.

Femap with NX Nastran also provides “full control of the analysis models,” such as the ability to remove layers or volumes to vary the analysis. Brotherton compares what Femap with NX Nastran delivers to the old MSC.Nastran by saying, “MSC.Nastran is like a photo viewer and Femap with NX Nastran is like Photoshop. There’s a lot more you can do with your models.”

In the carpentry world, there is an adage, “Measure twice, cut once.” Brotherton says, “In the mechanical engineering world, we use Femap with NX Nastran to calculate twice so we only test once. This pays off in time to market, lower costs and safer products on the roads. In today’s global market, we’re as likely to see our wheel components in the Outback of Australia as we are on an ‘out n’ back’ to the neighborhood grocery store. We must design our products with care and Femap with NX Nastran plays a big role in helping us do that.”

By switching to Femap with NX Nastran, KIC got an FEA solution that is both easier to use and more powerful than its previous system. That, combined with excellent support from a local VAR and UGS, is proving to be a winning combination — and a solution that positions the company well for the future.

Caren D. Potter is a freelance writer living in northern California. She has been writing about CAD/CAM for 20 years. Send your comments about this article through e-mail by clicking here. Please reference “FEA Turn” in your message.

KIC Holdings
Vancouver, WA

Predictive Engineering
Corvallis, OR

UGS Corp.
Plano, TX