Werner Hufenbach

Defects in laminated composite structures like voids and impact damages have a major influence on the fatigue behaviour. These defects may occur in the manufacturing process and during lifetime of composite parts and lead to matrix cracks within single layers and to delaminations between adjacent layers with different fibre orientations. We investigated the relationship between voids and impact damage and fatigue lifetime. Specimens made of a glass fibre non‐crimp fabric were produced by vacuum assisted resin infusion. Voids were introduced by air‐bypass simulating a leakage during the vacuum assisted resin infusion‐process. Impact damage was induced using a canon. Stringer‐panels with the basic dimensions of 1000 mm × 1200 mm and a radius of 1980 mm were tested under multiaxial load situations in a hexapod test rig and a tension/compression‐shear test rig.

Future mobility applications are characterized by a high level of resource efficiency due to the application of novel lightweight materials and function‐integrating, multi‐material design concepts. Textile thermoplastic composites in particular pave the way for lightweight components characterized by highly specific mechanical properties and efficient production processes. This essay presents the strategy pursued by the Collaborative Research Centre SFB 639 “Textile‐reinforced composite components for function‐integrating multi‐material design in complex lightweight applications”, a concept for the holistic analysis of complex process chains for hybrid yarn textile thermoplastic (HYTT) composites and the idea behind the innovative FiF electric mobility technology demonstrator vehicle.

The application of Time–Temperature Superposition (TTS) for the determination of isochronous stress–strain diagrams of textile‐reinforced thermoplastic composites under compressive load in laminate thickness direction is evaluated. Creep experiments are carried out at various temperature and load levels. The creep curves are assembled to master curves using horizontal and vertical shifting. These curves are compared to long‐term creep data and an isochronous stress–strain diagram is determined.

Orobates pabsti, a basal diadectid from the lower Permian, is a key fossil for the understanding of early amniote evolution. Quantitative analysis of anatomical information suffers from fragmentation of fossil bones, plastic deformation due to diagenetic processes and fragile preservation within surrounding rock matrix, preventing further biomechanical investigation. Here we describe the steps taken to digitally reconstruct MNG 10181, the holotype specimen of Orobates pabsti, and subsequently use the digital reconstruction to assess body mass, position of the centre of mass in individual segments as well as the whole animal, and study joint mobility in the shoulder and hip joints. The shape of most fossil bone fragments could be recovered from micro-focus computed tomography scans. This also revealed structures that were hitherto hidden within the rock matrix. However, parts of the axial skeleton had to be modelled using relevant isolated bones from the same locality as templates. Based on the digital fossil, mass of MNG 10181 was estimated using a model of body shape that was varied within a plausible range to account for uncertainties of the dimension. In the mean estimate model the specimen had an estimated mass of circa 4 kg. Varying of the mass distribution amongst body segments further revealed that Orobates carried most of its weight on the hind limbs. Mostly unrestricted joint morphology further suggested that MNG 10181 was able to effectively generate propulsion with the pelvic limbs. The digital reconstruction is made available for future biomechanical studies.