Minimize vehicle weight
Integrate optimization methods at the very early stages of the development process through optimization centers
•Lightweight, high performance design
•Manufacturing cost savings
자동차의 개발 프로세스는 여전히 내구, 충돌안전 등의 성능에 촛점을 맞춰서 진행되며 경량화에 대한 관심은 주요성능들의 개발보다 뒤에 있어 왔습니다. “최적화센터” (OC) 컨셉을 통하여, Altair ProductDesign 팀은 경량화와 주요성능들을 동시에 만족하는 혁신적인 디자인 모델을 개발하였습니다. 본 글은 하나의 부품부터 전체 차량까지 최적화 과정을 거치는 이른바 “CAE Weight Management” 에 대하여 소개하고 있습니다.
The automotive development process is still focused on objectives such as durability and crash safety, while weight is often limited to the very end of the design process. Through the establishment of the “Optimization Center” (OC) concept, Altair ProductDesign has developed an innovative design model combining performance features with weight reduction goals. This article describes the OC concept dealing with everything from the optimization of single components to an entire optimization process known as “CAE Weight Management”.
During the last few years, an increase in engine efficiency has been achieved across the automotive sector but these days, weight reduction is increasingly seen as the next step to lower the energy consumption and CO2 emissions of vehicles. Automotive manufacturers have started to not only look at the overall fleet emissions of CO2 , but have also begun to realize the advantages of weight reduction in a vehicle’s overall lifecycle. To obtain the best possible results, it is important to give as much priority to weight goals as to other functional attributes such as durability or crash safety.
An early combination of weight goals with these attributes enables a better design of components and assemblies while lowering the overall development effort. In Altair ProductDesign’s OC concept, a consulting team of highly qualified specialists follow this strategy and are able to break a negative weight spiral or even turn it around.
The Gateway to Design Innovation
The successful implementation of Optimization Centers throughout the aerospace industry has already resulted in significant weight savings on metallic and composite components. Pilot projects in the automotive industry have proved – with similar significant weight savings – that Optimization Centers can also bring advantages to this sector.
Automotive engineers have different weight reduction methods at hand, from the development of new designs or use of new materials to the application of an alternative manufacturing approach. Several of these strategies combined in an optimal manner can reveal opportunities to reduce unnecessary material. Form, material and production methods can be tuned to meet the optimal requirements.
Computer aided engineering (CAE) methods, such as structural optimization, are being applied to find and exploit this weight saving potential. The success of CAE optimization depends on how and when optimization methods are applied to the development process. The question “how” is answered best by placing it strategically within the context of project organization and it should be handled as closely as possible in collaboration with the design department. The answer to “when” is simply “the earlier the better”, with “simulation driven design” being the term which best summarizes this approach.
Tailored Optimization Centers
The concept of an Optimization Center has been developed to simplify the access to, and to enhance the benefit of, CAE optimization. Initially introduced to reduce the mass of individual components by changing their form, Optimization Centers have developed into a consulting approach for functional concepts and material decisions on an assembly level. The Altair ProductDesign concept of Optimization Centers provides close cooperation of optimization experts (including topology, topography, form and parameter optimization), who are made available to work on-site at the customer site and offer individual services on an exclusive basis. Under this approach, the effort of integrating optimization into the development process can be kept to a minimum. Every OC is scalable as it is possible to add additional resources to every team as needed.
Additionally, Altair ProductDesign recommends including the customer’s staff into the project team to foster knowledge transfer within the group, and questions such as available design space, possible manufacturing processes or the relevant functions can be discussed and answered quickly, leading to a minimum loss of communication and a maximum output. Depending on the requested level and integration of the Optimization Center, the experts will work directly and closely with each department involved.
The first level of an Optimization Center is the direct cooperation with the person responsible for components within each functional group or team. Usually, since the components’ material and production processes are already pre-defined, the experts can directly search for unused and removable material. An overall assessment of cost effectiveness of components to control resources by importance is not done at this level.
The next level of method integration is based on cooperation with the OEM’s project managers of the systems or of the full vehicle. Those engineers have the power to change functionality within the system or vehicle, which offers a higher potential for optimization since it is not necessary that each component becomes lighter to reach the system’s optimum. It is possible that single components – due to a change of function – might even be heavier, but with an overall optimization of the system, this can be more than compensated for in other areas. At this level of method integration, it is also possible to do an overall assessment of cost effectiveness. Since the entire system is analyzed, the engineers can apply advanced selection processes to prioritize certain topics.
CAE Weight Management
The direct support of the weight management department of an OEM is known as “CAE Weight Management“. With the implementation of CAE Weight Management into the weight management department, the team gains direct access to all available knowledge of the CAE studies (concept optimization, feasibility studies, robustness analysis and stochastic assessments) and can also request these types of studies to be made, to gain as much information on weight and performance as possible. In this way, the weight management department can draw better and more reliable conclusions regarding the development, and can be more precise on the input requirements needed to reach the weight goals. Information that an OC can deliver to the weight management department includes:
• an early understanding of the optimized basic structure and the associated mass.
• an understanding of the impact on weight when using carry-over parts or systems.
• an early understanding of the impact on weight of different concept and design directions.
The earlier and more broadly an OC is integrated into a development process, the more efficient the results will be. This rather simple formula describes the principal of the success of an OC. Early in the development process of a vehicle, the engineers are usually still highly flexible in their design. This should be leveraged, because at this stage it is decided if cost and timing, in relation to the defined functionality and weight goals, can be kept until later in the development process. In this phase, weight management still has every possible design freedom and can make use of it by applying the OC and the CAE Weight Management strategy to reach optimum results. If the engineers can make reliable predictions on the system‘s weight and direct weight savings early, they will be able to save up to the same amount in secondary weight . The further the process proceeds, the less it can be positively influenced. The probability that compromises in function and weight have to be made, or that the cost or time frame has to be adjusted, is higher at a later stage in the development process.
Value of an Optimization Center
What is the actual added value an OC brings to a development process? The benefit lies within the detailed knowledge of the OC team, in a profound prediction of the consequences of decisions that need to be made early in the development process and in the standardized approach of an OC. Properly applied, the OC will check the outcome of the options that have to be evaluated as early as possible and detects the available weight reduction potential. All suggestions the OC makes will consider the robustness of the predictions. An OC will constantly work with the customer’s engineering staff to streamline processes.
CAE Weight Management offers an improved understanding of the development progress, as the results of the CAE analysis and the intensive exchange with weight functions will provide the project management with predictions concerning performance, cost, and timing. As the project management is able to react earlier to erroneous development directions and can lead the project into the desired direction, development risks are minimized.
Real World Examples
Altair ProductDesign’s OCs have already been successfully implemented at several companies within the aerospace industry including Airbus. Based on these successes, pilot projects have been carried out in the automotive industry for clients such as Ford. The major goal of these projects was the demonstration of the potential performance of the first level of integration of an OC.
During the pilot projects, two existing vehicles (platform F250/350 and Ford Transit) were analyzed and 50 components of the F250/350 as well as 12 components of the Transit have been identified for further research. To save time and money, the project was handled in two steps. In a first step, Altair ProductDesign and Ford engineers checked each component for weight saving potential. Subsequently, the OC team created a ranking system, comparing the cost and customer benefits achieved by saving material to the effort, new tools or production methods that changes in the design would require. In a second step, the engineers then chose which components should undergo a detailed weight optimization (17 of the F250/350 and 6 of the Transit).
The team engineers further specified production and assembly restraints for these components, before applying the topology, topography and size optimizations. A subsequent finite element (FE) analysis proved that all mechanical functions concerning strength and stiffness were unchanged. The result: all in all it was possible to save an average of 19% weight for the F250/350 components and 13% of those from the Transit.
Summary and Outlook
To receive profitable material savings and to truly meet CO2 emission targets, weight goals consequently have to be followed up even more. Based on Altair ProductDesign’s OC concept, the OEM can be supported to reach those goals of weight reduction with several levels of integration. The OC finds the weight potential in each vehicle, combines them with the necessary changes of material and production processes, and enables the assessment of cost and value. Especially for existing weight management functions at the OEM, the CAE Weight Management program is a valuable addition. To truly exploit the maximum potential of weight reduction it is important to include the OC as centrally as possible within the vehicle development team and to start with the optimization as early as possible. But even if implemented at a later point in the development process, an OC can still deliver significant successes. The pilot projects at Ford and other OEMs show that the implementation of even the first level of an OC can already lead to double figure weight savings.
 Lutsey, N., 2010. Survey of Vehicle Mass-Reduction Technology Trends and Prospects. PowerPoint Prsentation, El Monte, California.
 Bjelkengren, Catarina, 2008. The Impact of Mass Decompounding on Assessing the Value of Vehicle Leightweighting. Thesis Dual Degree of Master of Science, Massachusetts Institute of Technology.
About Altair ProductDesign
Altair ProductDesign is a global product
engineering and design company of more than 500 staff. As a division of Altair Engineering, Altair ProductDesign is best known for its market leadership in combining human and computer creativity to fuel innovation, automate processes and develop new methods.