Materials to reduce vehicle weight

A new generation of materials management technology will open a window on lighter, more efficient vehicles.

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March 25, 2015
Leo Kilfoy
Manufacturing

European and North American mandates for lowering fuel consumption and tailpipe emissions put enormous pressure on automotive OEMs to improve existing vehicles’ mileage and develop efficient new designs. The U.S. corporate average fuel economy (CAFE) standard alone rises to 54.5mpg by 2025, which means automotive OEMs are on the spot now to deliver substantially better performance during the next 10 years.

The most promising route to greater fuel efficiency is reducing the vehicles’ weight. An automobile’s weight is responsible for more than two-thirds of the energy needed to move it. As a result, many OEMs are accelerating the adoption of advanced materials to reduce the weight of automobiles and trucks.

Composites, reinforced plastics, and lightweight steel and aluminum, are being deployed across the automotive industry at record rates to improve fuel efficiency. Automotive OEMs are integrating new materials into parts and assemblies in existing designs and developing completely reimagined platforms around them, such as the BMW i3 and i8.

New material systems provide significant benefits in specific weight and stiffness. However, because of their variability due to new manufacturing methods and engineers’ lack of familiarity with them, new material systems demand significantly more and different types of testing – potentially increasing up-front cost. This expansion of testing obligates OEMs to rethink how material systems are managed, and how they must evolve to support wider uses of new materials.
 

Managing advance materials

Traditional metals and plastics have been used in automotive design for decades, so engineers have amassed an enormous volume of knowledge about their behavior. Traditional materials behave isotropically, which means they behave more consistently than new materials with anisotropic properties. For example, a part made of steel will be uniformly stiff throughout its geometry. A part made of a new material, such as a composite, can be manufactured to be stiffer in one area than another.

That variability in the new material creates opportunities to reduce weight, but it also complicates determining how parts and assemblies deform and fail. That variability is a wholly new entry in automotive engineering: the idea that the material itself is a design variable that can be optimized.

Given this new universe of variables, automotive OEMs must meet an entirely new set of business needs before they can widely integrate new materials into vehicle designs. Most of them revolve around the need to collect, manage, and apply new material and testing data.

It is estimated that the number of tests in a composite vehicle program – compared to its metallic counterpart – has increased by an order of magnitude, causing a significant increase in workload, processing, and data management. That increase creates three critical business needs.

The first is to capture testing data in a logically organized, searchable, and automated manner. Reducing test data into properties that can be used in design and analysis needs to be seamless and efficient.

The second need is to track all of the material test data. New material systems require capturing not only the test data, but also the process and manufacturing data that went into making material test specimens. This includes tracking the manufacturing process, environment (such as humidity or temperature throughout the process), and material data (shelf time, etc.). Changes in any of these conditions can greatly affect test data.

The last need is to simplify the amount of physical testing to reduce cost and shorten development cycles. Reducing the number of physical tests can be achieved using simulation based on the principals of integrated computational materials engineering (ICME). Accurately building and simulating a physical specimen test virtually would lower cost and development time, providing a direct ROI.

This simulation data should be managed and maintained in the same system as the physical data. However, this approach requires mixing disciplines of simulation, material science, and high-performance computing in integrated technology systems. Those systems do not yet exist, but they are approaching rapidly as the need for them evolves.





 

Material data management

The foundational technology for integrated simulation/materials data systems emerged when material design data management tools first hit the market in 1989 with the introduction of MIL-HDBK5 and Mvision, the first commercially available materials database and materials data management system. PDA Engineering developed them in response to an Air Force contract to improve materials management.

A market arose around those products and spawned innovations through 2000. Software vendors developed digitized data banks for reference, design, and standards data, and integrated materials data management tools, with computer-aided engineering (CAE) and design (CAD) systems, and product data management platforms. They provided the ability to store data, and reduce it into quantities acceptable for simulation, searching, and comparing.

An emerging generation of software is extending those capabilities and adding functions essential to integrating material data into automotive design processes:

  • ICME support to reduce the cost of testing by enabling better material characterization on the front end of the design process
  • Automated data management to make material characterization less labor intensive
  • Transparent management of processes such as data import, reduction, export, and automated traceability of data and processes from import through use in simulation
  • An upgradeable IT framework with easy integration paths between applications and data sources
  • Collaboration functionality that enables engineers to easily request new data sets, integrates approval processes, and separates released and non-released data
  • Security in the form of access control, auditing functions, and fine-grained data access
  • Integration with common CAE, CAD, product data management, and desktop tools such as Excel
  • Ease of use for front-line design engineers

This new generation of materials management system will provide a holistic environment to address the needs of the front-line automotive engineers. Such a system must put materials in the forefront of engineering to use materials as an essential design variable to innovate. The ability to model material properties quickly, easily, and in detail is essential to adoptioning new materials that will make automobiles lighter, more fuel efficient and, ultimately better for the environment.

 

MSC Software
www.mscsoftware.com


About the author: Leo Kilfoy is the general manager of Engineering Lifecycle Management at MSC Software, and can be reached at leo.kilfoy@mscsoftware.com.