Punching Holes in Conventional Lightweighting Techniques
David Mason, Vice President of Global Automotive, Altair Engineering
Any business traveler who has packed a suitcase inherently understands the most effective approach to lightweighting. If the luggage is too heavy to lift, everything inside could be transferred to a somewhat lighter-weight bag, but clearly the best solution is simply to remove any of the contents that are not essential to the trip.
The same principle applies to lightweighting vehicles. The industry should not focus solely on replacing heavy materials with lighter ones. Rather, to gain the most benefits, we should concentrate on actually removing material. Whether we punch holes in the product, thin out its form or reshape its entire look, optimization technology has made it possible to eliminate material where it is not needed without sacrificing strength, performance or durability.
Optimization technology can recommend multiple ways to extract material from a product, significantly reducing its weight. Often such revamped designs present options that engineers never would have considered on their own. In other instances, relatively small changes in the original design can produce exceptional results, for example, by reducing the thickness of materials where support and durability are not impacted.
The increased use and success of optimization is placing lightweight material removal (LMR) on equal footing with lightweight material substitution (LMS); and, going forward, lightweighting will encompass a dual-pronged strategy of both removing and substituting material. Leaving half of the strategy out of the conversation leaves valuable weight savings on the table. The need to elevate our thinking about material removal has become even more urgent with the 2025 federal fuel economy guidelines that require vehicles to average 54.5 mpg. The combination of both removal and substitution will dramatically increase the auto industry’s progress toward better fuel economy. The next generation of lightweight automotive innovations will be realized when we begin to practice both material reduction and substitution for smarter design.
Meeting the new CAFE goals will require a combination of technologies from powertrain efficiency improvements, alternative powertrains, to lightweighting with alternative materials and, simply, material removal. A great challenge in introducing these technologies is the incremental cost, and this is where material removal really shines, as the incremental cost is typically small. In some cases, it even presents a cost savings.
In developing lightweight solutions, automakers must consider a number of factors:
Different manufacturing and assembly processes available
The tradeoff between performance characteristics
The customer-use environment and its impact on materials
How to design with the right material in the right place
Optimization technology can help balance these factors and serve as a critical tool for today’s automotive engineering challenge. Many companies already have discovered its value. Volkswagen has used optimization to reduce bracket weight by 22%, and Tallent Automotive cut chassis mass by 25%. Ford Motor Co. reports using topology optimization, for shape and material distribution decisions, to reduce the mass of a bracket by 27% while improving its performance by nearly 30%, for a first-year’s saving of more than $1.1 million.
The value of using optimization technology to design lightweight vehicle components was evident among the applications of manufacturers entered into the Enlighten Award Competition, an annual program developed by Altair Engineering and the Center for Automotive Research (CAR) to honor the industry’s greatest achievements in weight savings. Several of the applications in the 2013 competition presented optimized structures that ranged from a steering wheel and crankcase to an entire optimized body-in-white.
The winning entry was a BASF thermoplastic composite front seat pan in which the wall thicknesses were reduced using virtual simulation technology to identify where material could be removed without negative impact to performance. The weight of the component was lowered by 45% (1.5 kg to 0.8 kg) compared to the original design.
A culture of optimization is beginning to emerge within the auto industry. This efficient approach to lightweighting offers the opportunity to advance vehicle fuel efficiency significantly, as well as spark an overall shift in thinking among designers and engineers.
This article was first published in the 2013 edition of the Motorized Vehicle Manufacturing Yearbook.
Published Date : 11/6/2013