Materials testing at TU Dresden using integrated computer tomography

The Institute of Lightweight Engineering and Polymer Technology (ILK) at the Technical University of Dresden performs wide-ranging research and development work in the field of load-adapted lightweight structures and systems. The Institute follows a cross-material, cross-product approach encompassing the entire chain of development – material, design, simulation, production, prototype, test, quality assurance, cost. To enable analysis of the complex, non-linear behavior of lightweight materials in even greater detail, ILK now has access to a Zwick testing machine with integrated computer tomography.

ILK’s core area of expertise lies in developing, designing and optimizing components and systems for high-performance lightweight construction, as well as prototype production. Depending on requirements, all classes of materials, from steel to aluminium, magnesium and titanium to plastics to ceramics, are included in accordance with their design property profile, together with short-fiber, continuous-fiber or textile-reinforced composites.

ILK has opted for a 250kN Zwick testing machine to enable optimization of the design of lightweight structures under static loadings and to achieve a better understanding of the failure phenomenology of structures of this type. The multiaxial tensile/compression-torsion testing machine with integrated computer tomography will be used to carry out investigations into damage and reliability of multi-component materials. Micromechanical processes such as crack formation and crack opening are correlated with the measurable response behavior (stiffness, strength). Specimens are subjected to combined tensile, compression and torsion loads; during loading of the specimen the computer tomography receives a trigger signal to x-ray the specimen under load in various positions. This enables direct, space-resolved visualization of the damage behavior of multi-component materials during loading. The goal is to achieve a resolution of approximately 1 µm.

The Zwick single-screw testing machine features extra-wide column spacing and extra load-frame height to enable the computer tomography to be integrated into the test area, while a 2000Nm torsion drive is mounted in the upper crosshead to enable application of torsional moments to the specimen. Torsional moments and tensile and compression forces are each measured by a transducer. The trigger signal for computer tomography measurement is sent electrically via a Zwick I/O module, while the test sequence is programmed and the test results evaluated and displayed via the testXpert Multiaxial Master Test Program.