Characterization of plastic-metal hybrid composites joined by means of reactive Al/Ni multilayers - evaluation of occurring thermal regime. - In: Engineering for a changing world, (2023), 4.3.056, S. 1-16
Present challenges in material science and joining technology are ever more subject to the desire for lightweight construction and engineering. Plastic-metal composites are suitable material combinations but also require the development and investigation of appropriate joining technologies. A particularly promising approach is the application of reactive multilayer foils. As an innovative method, these foils provide the possibility of flexible and low-distortion joining of dissimilar materials. The underlying reaction mechanism offers fast exothermic reaction propagation with well-known exothermic power output while the energy source is introduced directly into the joining zone. In this work, hybrid lap joints between semi-crystalline polyamide 6 and structured austenitic stainless steel X5CrNi18-10 were joined using reactive Al/Ni multilayer foils. The self-propagating reaction provides immediate temperatures that are well above the melting point of used plastic but decays rapidly after only a few milliseconds. To support ongoing investigations regarding composite formation, analysis of occurring thermal regime is in the focus of this work. Conducted experiments are supported by accompanying thermal simulation in ANSYS Workbench. Besides the estimation regarding sensitivity of thermal material parameters the evaluation of formed melting zone and resulting thermally influenced area is a central topic.
https://doi.org/10.22032/dbt.58913
Influence of microstructure and microgeometry of the probe on friction stir welding of AA 6060 T66. - In: Engineering for a changing world, (2023), 2.1.114, S. 1-2
https://doi.org/10.22032/dbt.58854
Investigation of a quantified sound probe for stud weld quality measurement with numerical simulation data. - In: Engineering for a changing world, (2023), 2.1.065, S. 1-8
Drawn arc stud welding with ceramic ferrules is a widely used joining process for joining sheet metal to studs, which can be threaded or sheared. During the welding process, various irregularities can occur which adversely affect the resulting mechanical properties. Arc blowing is one of the most common process defects. Arc blowing can result in an asymmetric weld bead which can increase the failure rate of the stud. An approach to stud testing is given in DIN ISO EN 14555. A sound probe carried out by an experienced welder provides qualitative information about the weld bead. The sound probe causes the stud to vibrate at its natural frequencies. If the eigenfrequencies can be calculated for each weld bead shape, the sound probe can be quantified. To this end, a new simulation approach is presented which allows the rapid calculation of the eigenfrequencies of the stud with different weld bead shapes. A data set is also generated and analyzed.
https://doi.org/10.22032/dbt.58853
Directed energy deposition-arc (DED-Arc) and numerical welding simulation as a method to determine the homogeneity. - In: Engineering for a changing world, (2023), 2.1.036, S. 1-17
This research presents a hybrid approach to for the prediction of the homogeneity of mechanical properties in 3D metal parts manufactured using directed energy deposition-arc (DED-Arc). DED-Arc is an additive manufacturing process which can offer a cost-effective way to manufacture 3D metal parts, due to high deposition rate of up to 8 kg/h. Regression equations developed in a previous study were used to predict the mechanical properties of a wall structure using only the cooling time t8/5 calculated in a numerical welding simulation. The new approach in this research paper contains the prediction of the homogeneity of the mechanical properties, especially hardness, in 3D metal parts, which can vary due to localized changes in t8/5 cooling time provoked by specific geometrical features or general changes in dimensions. In this study a method for the calculation of the hardness distribution on additively manufactured parts was developed and shown.
https://doi.org/10.22032/dbt.58852
Empirical study on DED-Arc welding quality inspection using airborne sound analysis. - In: Engineering for a changing world, (2023), 1.3.055, S. 1-12
This study explores the potential of audible range airborne sound emissions from Gas Metal Arc Welding (GMAW) to create an automated classification system using neural networks (NN) for weld seam quality inspection. Irregularities in GMAW process (oil presence, insufficient shielding gas) may lead to porosity imperfections in weld seams. Using Directed Energy Deposition-Arc additive manufacturing, aluminum (Al) and steel wall structures were produced with varying shielding gas flows or applying oil. Acoustic emissions (AE) generated during the welding process were captured using audible to ultrasonic range microphones. Mel spectrograms were computed from the AE data to serve as input to NN during training. The proposed model achieved notable accuracies in classifying both Al weld seams (83% binary, 68% multi-class) and steel welds (82% binary, 58% multi-class). These results demonstrate that employing audible range AE and NN in GMAW monitoring offers a viable method for low-latency monitoring and valuable insights into improving welding quality.
https://doi.org/10.22032/dbt.58732
Einseitiges Widerstandsschweißen von Kunststoff und Metall - mechanische Eigenschaften und Oberflächenwechselwirkung. - In: DVS Congress 2023, (2023), S. 788-796
Kurzfassung S. 40
Akustische Kontrolle von Rührreibschweißnähten im Rahmen der Qualitätssicherung. - In: DVS Congress 2023, (2023), S. 641-649
Kurzfassung S. 33
Charakterisierung der geometrischen Verschleißeigenschaften von Rührreibschweißwerkzeugen und Entwicklung einer Methodik zur Abschätzung des maximal ertragbaren Verschleißes. - In: DVS Congress 2023, (2023), S. 634-640
Kurzfassung S. 32
Direct Energy Deposition-Arc - Einsatz von Kühlgasdüsen zur in-situ-Bauteilkühlung. - In: DVS Congress 2023, (2023), S. 545-554
Kurzfassung S. 28
Simulationsbasierte Optimierung der zeitabhängigen Pulsleistung beim Laserstrahlschweißen von Aluminiumlegierungen zur Vermeidung von Heißrissen. - In: DVS Congress 2023, (2023), S. 471-479
Kurzfassung S. 23