The application of molded wood parts as an alternative, innovative and sustainable multi-material system (MMS) for structural, resource-efficient and sustainable components within the body shell is a new approach in light-weight constructions. In many of the cases where a structural application of FRP is being considered, they can principally be substituted by wood-based MMS. Although there are great challenges; wood has the potential to fulfill the demands of the present technical appliances and social requirements. Actual results offers the first systematic approach to use wood in structural applications. The main properties and demands, which correspond with those of the specific original structural components, could be met. So, as regarding performance and reproducibility, it is possible to apply a wood-based material in technical appliances. Furthermore, material models have been designed and concepts for the repair and recycling of the wood-based MMS were developed

The use of micro fibres in Ultra-High-Performance Concrete (UHPC) as reinforcement increases tensile strength and especially improves the post-cracking behaviour. Without using fibres, the dense structure of the concrete matrix results in a brittle failure upon loading. To counteract this behaviour by fibre reinforcement, an optimal bond between fibre and cementitious matrix is essential. For the composite properties not only the initial surfaces of the materials are important, but also the bonding characteristics at the interfacial transition zone (ITZ), which changes upon the joining of both materials. These changes are mainly induced by the bond of cementitious phases on the fibre. In the present work, three fibre types were used: steel fibres with brass coating, stainless-steel fibres as well as nickel-titanium shape memory alloys (SMA). SMA fibres have the ability of “remembering” an imprinted shape (referred to as shape memory effect), triggered by thermal activation or stress, principally providing for superior performance of the fibre-reinforced UHPC. However, previous studies have shown that NiTi-fibres have a much lower bond strength to the concrete matrix than steel fibres, eventually leading to a deterioration of the mechanical properties of the composite. Accordingly, the bond between both materials has to be improved. A possible strategy is to roughen the fibre surfaces to varying degrees by laser treatment. As a result, it can be shown that laser treated fibres are characterised by improved bonding behaviour. In order to determine the bond strength of straight, smooth fibres of different metal alloy compositions, the present study characterized multiple fibres in series with a Compact-Tension-Shear (CTS) device. For critical evaluation, results obtained by these tests are compared with the results of conventional testing procedures, i.e., bending tests employing concrete prisms with fibre reinforcements. The bond behaviour is compared with the results of the flexural strength of prisms (4 × 4 × 16 cm³) with fibre reinforcements.

Producing joints of aluminum and copper by means of fusion welding is a challenging task. However, the results of various studies have proven the potential of friction stir welding (FSW) for manufacturing aluminum-copper joints. Despite the proven feasibility, there is currently no series application in automotive industry to produce aluminum-copper joints for electrical contacts by means of FSW. To make FSW as efficient as possible for large-scale production, maximized welding speed is desired. Taking this into account, this paper presents results of a parametric investigation, the objective of which was to increase the welding speed for FSW of aluminum and copper in comparison to welding speeds that are considered to be state of the art. Taguchi method was used to design an experimental plan and target figures of the investigations were the resultant tensile strengths and electrical resistances. Dependencies between input parameters and target figures were determined systematically. The optimal welding parameters, at which joints failed in the weaker aluminum material, included a welding speed of 700 mm/min. Consequently, it could be shown that joints with a performance similar to those of the base materials can be obtained using significantly higher welding speeds than reported in the relevant literature.