A5002850480- Welding Techniques and Residual Stresses
- Ultrasonics and Acoustic Wave Propagation
- Non-Destructive Testing Techniques
- Flow Measurement and Analysis
- Metal Forming Simulation Techniques
- Cellular and Composite Structures
- Advanced Welding Techniques Analysis
- Fatigue and fracture mechanics
- Mechanical Behavior of Composites
- Acoustic Wave Phenomena Research
- Adhesion, Friction, and Surface Interactions
- Microstructure and Mechanical Properties of Steels
- Supercapacitor Materials and Fabrication
- Metal Alloys Wear and Properties
- Additive Manufacturing Materials and Processes
- Thermography and Photoacoustic Techniques
- Advanced Sensor Technologies Research
- Underwater Acoustics Research
- Force Microscopy Techniques and Applications
- Engineering Structural Analysis Methods
- Gear and Bearing Dynamics Analysis
- High Entropy Alloys Studies
- Material Properties and Processing
- Engineering and Materials Science Studies
- Speech and Audio Processing
Fraunhofer Institute for Nondestructive Testing
2017-2024
University of Freiburg
2021-2022
Abstract The potential of a new design adhesive microstructures in the micrometer range for enhanced dry adhesion is investigated. Using two‐photon lithography system, complex 3D master structures funnel‐shaped are fabricated replication into poly(ethylene glycol) dimethacrylate polymer. diameter, flap thickness, and opening angle varied systematically. single characterized using triboindenter system equipped with flat diamond punch. pull‐off stresses obtained reaches values up to 5.6 MPa,...
Ultrasonic metal welding is an energy-efficient, fast and clean joining technology without the need of additional filler materials. Single spot ultrasonic aluminum to steel sheets using automotive materials has already been investigated. Up now, further studies close gap application-relevant multi-metal structures with multiple weld spots generated are still missed. In this work, two different arrangements presented, each consisting spots, joined 0.9 mm thick wrought alloy AA6005A-T4 1...
Ultrasonic metal welding (UMW) enables joining in the solid state at relative low temperatures with short cycle times. This technique is of particular interest for metallic glasses to each other or materials, because crystallization amorphous structure can be prevented due thermal loading and rapidity process. In this work, UMW applied join one 1 mm thick sheet a commercial wrought aluminum alloy (AA5754) 0.4 strip Zr-based bulk glass (AMZ4). The introduced heat process detected...
Abstract High precision ultrasonic time-of-flight measurement is a well known part of non-destructive evaluation used in many scientific and industrial applications, for example stress or defect detection. Although measurements are widely there some limitations where high noise distorted signals conflicting with the demand measurements. Cross-correlation based one strategy to increase reliability but also exhibits ambiguous correlation states yielding wrong results. To improve these new...
The manufacturing of hybrid materials such as nickel/polyurethane (Ni/PU) foams and 3D printed with the aid electrochemical coating lightweight structures leads to new materials, which can be used crash absorbers, but also for design applications. Optimizing quality developed necessitates a characterization on different scales regarding thickness distribution. ferromagnetic properties nickel enable remanent magnetization produced subsequent measurement resulting magnetic fields, so that...
Abstract A theoretical and experimental framework for novel metamaterial with programmable damping properties is presented. This material system able to switch between elastic-dominated damping-dominated regimes different overall stiffness under dynamic loading depending on the external stimulus. The unit cell combines an auxetic a bellow-like layer separated by interface through which amount of media flow can be tuned lateral strain. simplified analytical model derived analyse effect....
The cross-correlation function (CCF) is an established technique to calculate time-of-flight for ultrasonic signals. However, the quality of CCF depends on shape input In many use cases, can exhibit secondary maxima in same order magnitude as main maximum, making its interpretation less robust against external disturbances. This paper describes approach optimize signals measurements through coded excitation sequences. challenge applying sequences influence piezoelectric transducer outgoing...
Novel cellular materials promise a combination of high strength and low specific weight for sustainable energy‐efficient material design. Inhomogeneities the materials, such as varying coating thickness, are inherent to production process but require advanced characterization in order better understand mechanical properties. Herein, global local acoustic analysis nondestructive thickness on an open‐porous hybrid metal foam system is studied. Experiments numerical simulations carried out...
Vibroacoustic metamaterials offer an approach for the targeted damping of unwanted structural vibrations and noise by integrating periodically arranged resonators into a matrix bulk material. Fabrication using laser bed powder fusion process allows integration depots, leading to extension designable properties. Herein, adaptation acoustic methods is focused on characterization properties metamaterial plates. The investigated vibroacoustic plates are made polyamide PA1.2, combining material...