Robert Maier

Metal electrodeposition on additively manufactured lattice structures enables the creation of functionally graded hybrid components with enhanced mechanical properties. However, predicting coating thickness distribution remains challenging due to complex current density fields in intricate geometries. This study develops and validates a finite element electrochemical simulation model for predicting coating thickness distribution in lattice structures using COMSOL Multiphysics 6.1. The model incorporates Butler–Volmer electrode kinetics, mass transport limitations, and the Laplace equation for current distribution. Experimental validation was performed using FCCZ lattice structures electrochemically coated with nickel for 24 h at 200 A/m². CT scanning analysis revealed mean absolute errors of 5.25% between simulation and experiment after model calibration. The validated model successfully captures the exponential coating gradient from exposed edges to internal regions and provides a robust predictive tool for coating thickness distribution, which is essential for the effective design and optimization of electrochemically metallized lattice structures.

The reason for the failure of electric vehicle drives is increasingly current-induced damage to rolling bearings. Studies show that rolling bearings are more susceptible to current pass-through after the first occurrence of unwanted bearing currents. To investigate this effect, a test plan is introduced with variations in axial and radial loads, as well as rotational speeds. A new bearing is mechanically run-in for each test point and then subjected to a realistic voltage signal of gradually increasing amplitude. After the initial breakdown, the different voltage amplitudes are applied again to investigate the behavior after the initial breakdown. During the whole test, the maximum current, the duration and the dissipated energy of each breakdown are measured. The results provide insights into the processes after the initial breakdown and the stochastic nature of the breakdown behavior.

Resin flow in resin transfer molding may be strongly influenced by small heterogeneities in the fiber preform, such as narrow channels formed by bending and fitting into a mold. An evaluation of preform permeability in these regions of nonuniform packing is presented. The study incorporates an empirical and analytic approach to iteratively determine the permeability in these regions. Flowfront data were recorded for high fiber volume fraction woven fiber preforms. Edge gap width, injection pressure, and fiber volume fractions were varied. The flow front data were compared with numerical simulations to estimate enhanced permeability at the edges. The results indicate that, for high fiber volume fraction preforms, flow in the channel dominates for relatively small (≈ 2 mm) gaps.