Convincing auto makers to use more composites in mainstream vehicle production hasn’t been easy. For years, they simply could not justify the cost of paying for carbon fiber parts made of virgin material. The situation improved when recycled products began making their way to market. Now auto makers have yet another option in honeycomb sandwich panels.
The honeycomb structure has been the subject of plenty of study over hundreds of years. We humans are fascinated by what honeybees can do in terms of architecture and design. Our honeycomb structures are among some of the strongest in the world.
Engineers can use the same principles observed in the average beehive to create honeycomb sandwich panels for a variety of applications. And no, this is nothing new. Honeycomb sandwich panels have been around for years. They are just making their way to the composites sector for automotive applications.
Strong and Lightweight
The honeycomb sandwich panel consists of the honeycomb structure and two outer sheets that cover it completely. The outer sheets offer a smooth surface and lateral stability over the entire panel. Between the sheets is a strong and lightweight honeycomb structure that gives the panel its form and flexibility.
One of the best properties of honeycomb is the fact that it is lightweight. Each compartment in a honeycomb structure is a hexagonal compartment that looks like a little chamber with empty floor space at the bottom. You would think that the hollow nature of these individual chambers would make the honeycomb structure weak. However, this is not the case.
Each chamber has eight walls to carry its load. Simple physics dictates that the more load bearing members a structure has, the more weight that structure can support. Such is the case with the honeycomb structure. So many walls provides a tremendous amount of surface area over which to distribute load. The more densely the honeycombs are packed together, the more weight it can support.
However, empty spaces within the honeycomb chambers reduce overall weight. The honeycomb sandwich panel weighs significantly less than a solid panel. Thus, auto makers can reduce the weight of their vehicles by replacing some solid panels with honeycomb panels instead.
Recycling Makes Them Cheaper
All of this is well and good. However, the real selling point in terms of the auto manufacturing industry is cost. Honeycomb sandwich panels for automotive applications can be made with recycled carbon fiber that would otherwise have ended up as landfill waste. Recycled carbon fiber is measurably less expensive than virgin product. In short, honeycomb sandwich panels address the biggest composites concern in the auto industry: cost.
The one downside of recycled carbon fiber is that it does not offer the same strength as virgin material. But you don’t need the same strength for a lot of automotive applications. Take interior door panels, for example.
They do not have to be as strong as airplane wings or fuselage panels, like the aerospace carbon fiber made by Rock West Composites in Salt Lake City, Utah. For all intents and purposes, interior door panels are cosmetic. The same is true for the panels that make up your typical dashboard and center console. Make them from a carbon fiber-based sandwich panel material and you get acceptable strength in a lightweight material.
Expect to see more honeycomb sandwich panels in new cars as auto makers seek to reduce the weight of their vehicles even further. Between reducing fuel omissions and eventually transitioning to electric vehicles, they have no choice but to get the weight down as low as possible. Carbon fiber and honeycomb sandwich panels will play a crucial role in doing so.