Small-Scale Multiaxial Setup for Damage Detection Into the Very High Cycle Fatigue Regime

Abstract

Micro electro mechanical systems, coatings, and thin films contain materials that are often subjected to complex loading conditions and high frequencies. Therefore, the implementation of a resonant multiaxial fatigue setup for small-scale samples is of high interest. Finite Element simulations have been used to design small-scale samples which possess very close bending and torsional resonant frequencies.The bending and torsional modes are excited by two piezo actuators working either in or out of phase with one another. The bending and torsional amplitudes are measured independently by a laser and the actuator amplitudes are controlled by a Field Programmable Gate Array. The fatigue setup can be used with a varying range of sample sizes from centimeters down to tens of micrometers. The novel multiaxial resonant micro fatigue setup as well as results (fatigue damage for Ni and lifetime for Cu) from bending small-scale fatigue tests are shown and discussed.

Prediction of multiaxial high cycle fatigue at small scales based on a micro-mechanical model

“…In-phase excitation of piezoelectric actuators induces a bending load on the sample, anti-phase excitation causes a torsion load, and out-of-phase excitation leads to a multiaxial loading. The geometry of the samples was designed in a way that the resonance frequencies in bending and torsion modes were very close [30]. Bending and torsional displacements of the sample were measured using a laser beam reflected from the surface of the sample to an area detector.…”

“…(a) Test setup, (b) working principle, and (c) geometry of micro-samples used in multiaxial HCF experiments, dimensions are in (mm)[30,31].…”

Influence of Periodic Pauses on Fatigue Life of an Automobile Horn Bracket Under Variable Amplitude Loading

“…Load spectra are acquired in discrete points in the components, then they are filtered, have their frequency enhanced and then are applied to test components by actuators in a testing machine [2,21,22]. The loading devices can reach presently quite sophisticated setups [23], however, actual loading of a component, mounted in a structure will always be different. There is, however, at least one drastic difference between testing in a track and in a machine: in a test track the test must be paused periodically for the driver's comfort or due to mechanical issues, like maintenance.…”

Automated Quantitative Analyses of Fatigue-Induced Surface Damage by Deep Learning

“…This section does not cover the fatigue process nor the loading conditions, since this is described elsewhere [17], but rather focuses on the establishment of the data sets for learning the pixel-wise damage localization. The training and testing data sets were generated from stitched SE2 images of micro samples in the highly loaded regime after fatigue ( Figure 1) and its annotated correspondences.…”