21st February 2013 by Tony Norton
Success in developing the new generation of cars and trucks has demanded advancements in many arenas, including powertrains, fuels, materials, manufacturing methods and design. Computer-aided engineering tools from Altair have advanced as well allowing design engineers to improve vehicle efficiency and performance while at the same time lightening the vehicle structure. Altair’s Vice President of Global Automotive, Dave Mason offers answers to some of the most important questions about Altair’s role in the use of composites for today’s vehicles.
What role will modeling and FE analysis tools play in accelerating composites growth in the automotive sector?
Today, the use of finite element simulation and CAE is an established part of the design process for all OEMs confronting the challenges of increasingly complex products and high costs for physical test verification. Automakers have developed successful simulation processes to meet complex crash, NVH, durability, vehicle dynamics, thermal and aerodynamic requirements. These processes are evolving allowing for accurate simulation with advanced composite materials.
CAE simulation is already widely used in parts made of common metal and engineered plastic materials (particulate composites with short, long fibers) and is now offered for the most advanced new composites (i.e., continuous carbon-fiber laminates). The availability of reliable simulation technology will catalyze composites growth, bringing confidence to design engineers and management already comfortable with what CAE delivers for traditional metal-based vehicles.
One of the biggest roadblocks facing composites is the challenge of their integration into the existing infrastructure serving the automotive sector. Infrastructure challenges span the entire product lifecycle, from joining processes in assembly plants to paint lines, all the way to body repair shops. Ultimately, any future benefits from reductions in composites material cost or from more efficient manufacturing techniques may be less of a game-changer for growth if not paralleled with advancements in design technologies like CAE.
Can these design-engineering activities help to bring the cost of composites down to a level suitable for mainstream vehicles? If so, how? And in what timeframe?
Composites, and in particular laminate composites, are seen as costly alternatives to metals. In attempting to bring down the cost of composites, it is essential to use CAE-based optimization to reduce material usage and design the part efficiently.
For carbon-fiber laminate composites, however, software optimization goes beyond material saving alone. Optimization is a comprehensive solution aimed at guiding and simplifying the design of laminate composite structures. The design flexibility offered by composites derives mostly from the ability to tailor the material itself to the loading requirements. Optimization is the best strategy in the hand of design engineers to choose the right selection of laminate ply thicknesses, orientations and stacking. Unless an optimized design is followed, the results often will be a composite part overdesigned with redundant material that adds cost and weight.
Additionally the cost of an automotive component stems not just from the material itself but also from R&D, manufacturing and assembly of the components, which particularly for smaller productions may consume a larger portion of the final cost. CAE-based design helps easily identify opportunities for part consolidation, which is one of the tactical advantages of plastic with respect to traditional metals systems often built by assembling multiple smaller parts with multiple connections.
Does Altair’s composites modeling suite focus on manufacturing aspects as well as product design?
Altair’s composite modeling suite is mainly tailored to the needs of composites designer engineers, but it does so taking into account many of the constraints required by manufacturing. Design, manufacturing and assembly requirements are part of concurrent aspects of solid engineering targeted toward product simplification and cost savings.
In laminate composite software optimization, for example, the CAE analyst may control the minimum and maximum total laminate thickness, the minimum and maximum ply thickness, and the minimum and maximum percentage of a fiber orientation; may enforce constant thickness for a particular ply orientation; and may control balancing and symmetry constraints, ply angle drops, maximum number of consecutive plies of the same fiber orientation or other constraints and various ply book rules enforced in manufacturing.
Moreover, Altair’s HyperWorks Partner Alliance also offers Moldex, a leading injection-molding simulation solution that enables designers of plastic parts and molds to create in-depth simulation with the widest application range of injection-molding processes to optimize product design and manufacturability.
Where does composites-modeling technology go from here? Are any major advances on the horizon, or major challenges to be overcome?
Because of requirements dominated by the aerospace sector, academic research on composites, their characterization and CAE modeling technology have been principally focused on structures in the linear material behavior range (stiffness and fatigue) with margins of safety. The understanding of the dynamic performance, energy absorption and failure of composites is not yet as detailed, particularly for parts with complex geometry. Most of the published studies on composites are based on simple geometry, such as axis-symmetric tubes subject to quasi-static loads. For new automotive fibers, matrices and additives are being introduced into the market to improve composites’ performance and reduce cost. As a result, further penetration of composites in areas of the vehicle that affect crash performance face a major challenge. More detailed work on material characterization and modeling is beginning to take place and is required.
How has Altair’s automotive composites design business benefitted from its work for aerospace and/or defense?
The switch from aluminum-centric to composite-intensive airplanes has been a major undertaking for the aerospace industry and its suppliers. Altair in particular has invested significantly in new software technologies and broadened knowledge on composites among developers and the 700+ engineers of Altair ProductDesign. Years of composite focus for aerospace, military, racing and niche-vehicle applications has nurtured new CAE modeling methods for composites, new material models, material fittings techniques, failure modes, adhesive joining, optimization methods and laminate composite post-processing. These are great benefits that Altair now brings to its automotive customers.
Altair’s material-agnostic design approach also helps put the right material in the right place, taking advantage of the unique opportunities offered by composites in the most promising automotive applications.
What’s your personal outlook for the future of composites in structural automotive applications?
We have witnessed solid growth in the use of plastics and composites over the last decade. With the elevated attention on fuel efficiency, there is no doubt that this trend will continue. The increasing variety of low-volume niche vehicles and highly energy-efficient green vehicles will likely demand a growing amount of composite content as crashworthiness design requirements are facilitated. Mass use for automotive applications will require some significant innovations in manufacturing methods to bring down the current high production costs.
For the auto industry, composites are positioned as welcome solutions to many vehicle requirements, and Altair is positioned to deliver the analytical tools that will help ensure the success of composite materials.
This article is taken from Altair’s HyperWorks Insider Newsletter