“We had a lot of baseline data from our previous aluminum frames, so we had a really good idea about how strong the frames needed to be and what performance characteristics we wanted,” says Bosworth. “Once we introduced the thermoplastic carbon fiber, we were able to take advantage of the software and use it to its fullest potential.” He began with simple tensile test samples and matched those with physical tests. Next, he developed tube samples using the software and again matched those to physical tests.
“It wasn’t until I was much further down the rabbit hole that I actually started developing the frame model,” says Bosworth. Even then, he started small, first developing a computer model for the front triangle of the bike frame, then adding in the rear triangle. Afterward, he integrated the boundary conditions and the load cases and began doing the optimization.
“You need to start simple, get all the fundamentals down and make sure the models are working in the way you intend them to,” says Bosworth. “Then you can get more advanced and grow your understanding.” At the composite optimization stage, Bosworth was able to develop a high-performing laminate schedule for production and design for automated fiber placement.
Even with all his experience, developing the bike frame still presented challenges. “One of the issues with composites simulation is there are so many variables to getting an accurate result,” admits Bosworth. “I focused on not coming up with a 100 percent perfect answer, but using the software as a tool to get us as close as we could as fast as possible.”
He adds that composites simulation tools can steer you in the right direction, but without many months of simulation and physical testing, it’s still very difficult to get completely accurate results. “One of the biggest challenges is figuring out where your time is best spent and what level of simulation accuracy you want to achieve with the given time constraints,” says Bosworth.
Wading into the Simulation Waters
The sophistication and expense of composites simulation tools can be daunting, but Wollschlager encourages people not to be put off by the technology. “The tools are not prohibitive to small and medium-sized companies – at least not to the level people think they are,” he says.
Cost is often the elephant in the room, but Wollschlager says it’s misleading to think packages will cost a fortune. “A proper suite provides you simulation in all facets of composite life cycles – in the concept, design and manufacturing phases,” he says. “The cost of such a suite is approximately 20 to 25 percent of the yearly cost of an average employee. Looking at it in those terms, I just don’t see the barrier to entry for small to medium-sized businesses.”