Papers by Keyword: Multi-Material Design

Abstract: Mechanical joining techniques like clinching are standard joining techniques for processing aluminum and steel alloys in the automotive car body manufacturing. When using conventional methods, joints will have a high quality after a finally tool check on a specific joining press system. However, if the press system during manufacturing will changed, it can occur that joints get other quality values e.g. smaller interlock. The reason for that has multiple influences,this paper considers especially the press-sided ones. With optical measurements of press deformation and punch speed during real joining processes, new 3D-halfsymmetric simulation models were built up, which take into account of press-side behavior such as joining velocity and angular as well as lateral misalignment of the joining tools during clinching process. Sensitivity analyses identifies significant influencing variables. On the base of this, equations of quality changes can be determined. Finally, this allows better prediction of the modification about joint quality after a press change from system A to B or C during manufacturing.

Abstract: Multi-Material Design has been identified to be an important enabler for lightweight structures, especially with regards to the goals for the large-scale implementation of e-mobility concepts. A novel 3D-Hybrid technology has been developed to combine the advantages of metal and fibre-reinforced thermoplastics in one structural part. This leads to significant weight reduction in combination with an increase in functionality. Additionally, the amount of single parts can be reduced; these factors combined make the technology competitive with conventional steel-sheet design. Investigations on basic profiles showed the feasibility of the technology in single stage production processes and proved the superior performance of the structure compared to conventional design. Finally, a B-pillar demonstration structure was produced in a highly automated process and investigated in side-impact related component tests.

Abstract: Design engineers can choose from a large variety of materials in order to fulfill a certain function. In those fields of application with a lower level of complexity, it is often sufficient to manufacture the entire component in a “monolithic” manner from one single material. Concurrent, partly contradictory and, most probably, local requirements that must be fulfilled by a component often make material selection more difficult. As a consequence, it is often necessary to use several different materials with a local and functional orientation, which is a part of the multi-material design strategy. The potential of different materials can be used most effectively if this information is made available to the design engineers as early on in the design process as possible. The aim of the SFB 675 sub-project C7, therefore, is the development of a systematic design approach (Finite Element Design, FED) that focuses on finite component elements. As a result, the potential of the optimization of local properties is taken into consideration, and the interaction between the materials, production processes, and design can all be described.

Abstract: A major motivation for the development of new vehicle structures is, apart from the reduction of fuel consumption, is to decrease emissions which affect the climate. Therefore we also have to look at the reduction of vehicle weight and consequently at various strategies for lightweight construction. In the future steel structure concepts still show lightweight potential. But even more attractive potential for lightweight body in white structures could be realised by new multi-material design concepts and highly integrated light metal applications. Today’s research activities are focussed on the area of multi-material design, with the objective of placing the material with the best properties for the given requirements in the right position. Based on various methods of lightweight construction, techniques and tools, it is possible to find an optimum between lightweight design and costs. These activities will be illustrated by several research examples. One example will be the lightweight concept of the front module developed by the Institute of Vehicle Concepts (DLR) in the European research project -‘Super Light Car’ (SLC). By using aluminium in the front structure and the high pressure die casting strut tower the concept has a weight benefit of 32% compared to a steel reference structure. The methodology for reaching targets and requirements like weight reduction, crash performance and cost targets will be explained. Another example is a concept which is developed in the DLR project ‘Novel Vehicle Structures’. This concept shows the combination of different materials and a new construction method to increase front impact crash performance.

Abstract: The history of terrestrial transport systems on road and rail has always been influenced by material-related developments. These developments gave rise to various construction methods, taking into account the different requirements that transport systems had to fulfil and providing new approaches. The urgency of the CO2 problem will result in alternative power trains also establishing themselves on the market, in turn giving rise to new requirements and possibilities in the field of vehicle construction, over and above the established light weight design. Further development of materials is supported and supplemented by new material systems able to actively respond to the particular state of the system.

Abstract: Besides reducing fuel consumption, the chief motivating factor behind the development of new vehicle structures is the desire to decrease climate-affecting emissions. One approach to addressing this involves reducing the vehicle mass and, as such, the various strategies relating to lightweight construction. Various methods of lightweight construction are used as a basis for deriving the technically relevant criteria for designs and material concepts. The work conducted in this field today centres around the synthesis of construction method and material development with the objective of devising a multi-material-design [1, 2]. Modularisation is an economic approach aimed at shaping the diversification of the vehicle concepts and implementing this effectively [3]. As a result of hybrid and later fuel cell drives, the requirements on the vehicle concepts will continue to grow in future. Modularisation also sometimes opposes the striving for a high level of integration. The modular lightweight concept of the DLR aims at designing powertrain evolutions in a scalable and cost-efficient manner and in a way that retains the concept flexibility or, in some cases, even increases this. These approaches lead to the strategy known as “hybrid3”. This strategy not only involves matching different materials and various construction methods with each other, but also taking account of the integration of functional effects. This entails, for example, optimising the design of thin-walled structural components in terms of their vibratory or acoustic properties with structure- integrated, active materials. Further examples of the approach with “hybrid3” effects could be selectable surfaces or integrated energy conversion. The various development directions are depicted in the form of a roadmap and discussed on the basis of forward-looking examples from the field of vehicle construction.