Lightweighting done right can mean: better fuel economy, lessened wear and tear, and improved handling. In order to achieve these objectives, designers must start with the intended purpose and target market for the project. Once the market is defined, the design is created and the materials are selected… how can these deliverables be tested? Simulation is the critical step in the automotive design process for pre-production validation.
The primary consideration for lightweighting is material alternatives. Carbon fiber, aluminum, and many plastics can be used to replace traditional materials like steel. But how can we be sure that these materials can stand up to the force and energy they face on the road? Traveling at highway speeds creates a tremendous amount of momentum, which translates into catastrophic crashes every day. How can road safety standards continue to be at the forefront of the mechanical design?
FEA (Finite Element Analysis), a form of stress-testing is one way to simulate the potential impact and how that aluminum foam bumper will hold up in a collision. CFD analysis (Computational Fluid Dynamics) can measure areas such as heat transfer and aerodynamics. Lightweighting’s efficacy can be diminished if the aerodynamics are not up to par.
Now consider the example of the Ford F-150. This time last year they rolled out the aluminum body. According to an article in Fortune:
”Some analysts had warned that an aluminum-body truck poses a big risk for Ford because no automaker has ever mass-manufactured so many vehicles made from the metal at such a high rate of production… Ford switched from steel to aluminum to profit from the metal’s lightness and durability. Removing 700 pounds of weight from a full-size truck allows Ford to claim the best fuel efficiency in the category.” http://fortune.com/2015/03/16/ford-aluminum-f150-pickup-truck/
Ford took a gamble on the consumer mindset, that lightweighting was valuable and in demand. They also had to conduct an adequate amount of Q/A testing to ensure that the structural integrity of aluminum measured up to the more widely-accepted steel alloys. It appears the risk was worth it, as the crash tests have proven that aluminum is as safe if not safer. While material is a bit more spendy, consumers have demonstrated they are willing to kick down some extra cash for premium performance and materials when longevity and long-term efficiencies can reduce maintenance issues.
If the goal is cost-savings for the consumer then the following factors have to be in line:
- Cost of materials: plastics and aluminum are an economical material alternative, as compared to carbon-fiber
- Fuel economy: the lightweight auto will need to create more efficiencies at the pump
- Cost of Production: the ability to mass produce the parts and ease of assembly
In our next blog post in this series, we will review the impact CFD and FEA simulation has on the automotive design process and how it can be leveraged to shorten the time to market and improve end-product performance.