Optimal design and production of lightweight and high-performance Aluminium-Steel structural components

Safety and lightweight solutions are main focuses in today's automotive industry. Multi-material and lightweight structural components, such as aluminium-steel, in vehicle system with high-performance is deemed necessary to reduce greenhouse gas emissions. The key to success is a combination of multi-material product design, optimal material selection and cost-effective manufacturing processes for high volume production. The overall vision of the Optimals project is to enable multi-material solutions for high-performance aluminium-steel structural components with a total reduction of weight and manufacturing cost. The project has developed new principles for product design, principles for optimal material selection and innovative technologies for joining aluminium to steel. Successful implementation of the innovations will significantly contribute to the development of lightweight solutions, not just for automotive industry but also other industries and sectors, e.g., transportation industry, marine industry, green shipping as well as oil and gas industry. This will have great contribution to Norwegian climate target of at least 40% reduction of greenhouse gas emissions by 2030, compared to 1990 levels. The R&D activities and innovation in Optimals project has been driven and realized through industrial demonstrators, i.e., 1) crash-management system (CMS) and 2) automotive load-carrying structural component. Two joining processes, Cold Metal Transfer (CMT) and Hybrid Metal Extrusion & Bonding (HYB), have been developed to fabricate the demonstrators. The project has also developed a hybrid solution, combing the CMT and HYB process and taking the advantages of each process. Numerical simulations have been performed to support the development of the design principle and joining methods. The tests of demonstrators have been performed to evaluate the performance in addition to generic testing in laboratories. The R&D results in the Optimals project laid a solid foundation for future development of aluminium-steel structural components in vehicles. The project has also obtained better understanding of the Fe-Al interface properties and product performance, which are important for selection of materials for multi-material products. Moreover, the project also paved the way for commercialization and industrialization of the HYB technology.

The project has generated fundamental knowledge about steel-aluminium welded joints developed by industry partners and research partners. The first design experience with welded hybrid structures has been obtained. Two joining processes have been developed to make aluminium-steel structural components. The numerical tool has been further developed to simulate dissimilar materials joining processes. The R&D results will accelerate industrialization and commercialization of the HYB technology. Moreover, the project results will enable future lightweight solutions not only for automotive applications but also other applications, and thus contribute to the reduction of greenhouse gas emission.

Safety and lightweight solutions are ranked in the same priority in today's automotive industry. Structural components and crash management system (CMS) are critical parts in vehicle system to bear weight and increase safety. To achieve optimal lightweight solutions for structural components and CMS there is a need to combine different materials in multi-material solutions, e.g., aluminium and steel. The OPTIMALS project aims to solve the key technological challenges faced in the introduction of high performance components of aluminium steel combinations. The project will develop new principles for design, where also Design for Disassembly is taken into account, principles for optimal material selection for structural components and CMS as well as innovative joining technologies for metallic joining of aluminium to steel. The main objective of OPTIMALS project is to enable multi-material solutions for high-performance aluminium-steel structural components with a total reduction of weight and manufacturing cost. The key R&D challenges include: 1) to incorporate physics in joining processes, material properties into design stage of structural components in order to ensure high-performance; 2) to develop principles for optimal material selection supported by material database solutions and numerical modelling platform; 3) to develop robust joining technologies, where controlling of the formation of intermetallic compounds is the key challenge. Successful implementation of the innovations developed in OPTIMALS project will significantly contribute to lightweight solutions not just for automotive industry but also other industries and sectors. Delivery of customized multi-material products, boost of material production and commercialization of joining processes are the expected direct outcome when the innovations are implemented, which will ensure a sustainable growth of the participating partners.