http://popups.lib.uliege.be/2684-6500/index.php?id=210 Index terms fr 0 http://popups.lib.uliege.be/2684-6500/index.php?id=206 The Tribomechadynamics Research Challenge (TRC) was a blind prediction of the vibration behavior of a thin plate clamped on two sides using bolted joints. Specifically, the natural frequency and damping ratio of the fundamental bending mode were requested as function of the amplitude, starting from the linear regime until high levels, where both frictional contact and nonlinear bending-stretching coupling become relevant. The predictions were confronted with experimental results in a companion paper; the present article addresses the experimental analysis of this benchmark system. Amplitude-dependent modal data was obtained from phase resonance and response controlled tests. In the phase resonance test, a resonant phase lag between response and excitation was ensured via feedback control, and the excitation level was step-wise in-/decreased. In the response controlled test, the response level was kept fixed via feedback control. An original variant of response controlled testing is proposed: Instead of a fixed frequency interval, a fixed phase interval is analyzed. This way, the high excitation levels required outside resonance, which could activate unwanted exciter nonlinearity, are avoided. The consistency of the nonlinear modal testing methods, with each other, and with conventional linear tests at low amplitudes, is carefully analyzed. Comparisons of nonlinear-mode based predictions with direct frequency response curve measurements (at fixed excitation level) serve as additional cross-validation. Overall, these measures have enabled a high confidence in the acquired modal data. The different sources of the remaining uncertainty were further analyzed. A low reassembly-variability but a moderate time-variability were identified. The latter is attributed to some thermal sensitivity of the system. Two nominally identical plates were analyzed, which both have an appreciable initial curvature, and a significant effect on the vibration behavior was found depending on whether the plate is aligned/misaligned with the support structure. Further, a 1:2 nonlinear modal interaction with the first torsion mode was observed, which only occurs in the aligned configurations. All data (time series of nonlinear tests; linear modal properties) and post-processing methods are publicly available. Mon, 07 Oct 2024 10:32:51 +0200 Fri, 08 Nov 2024 11:39:05 +0100 http://popups.lib.uliege.be/2684-6500/index.php?id=206 http://popups.lib.uliege.be/2684-6500/index.php?id=219 Experiments and physics-based modeling efforts both show that the features within a jointed interface can have an outsized influence on the nonlinear dynamics of a large-scale structure. The interfacial features, including asperities and meso-scale topology, are often six to ten orders of magnitude smaller in scale than the structure itself, yet can significantly change the natural frequencies and damping of a structure and can lead to the premature failure due to wear if not properly designed. A significant amount of recent research has been invested in understanding and predicting the nonlinear dynamics of structures with jointed interfaces; however, there are many challenges that still remain before accurate predictions of a jointed structure's nonlinear dynamics and wear properties becomes accessible to design engineers. This article is a reflection of the outcomes of the 2023 International Workshop on the Mechanics of Jointed Structures in which the state of the art of joints modeling was assessed and future directions for research on jointed structures were identified. As such, this paper makes several recommendations for new research thrusts to improve the understanding of jointed structures in addition to highlighting the current state of the art and recent advances in modeling and experimentally characterizing jointed structures. Mon, 07 Oct 2024 10:50:33 +0200 Wed, 06 Nov 2024 14:26:11 +0100 http://popups.lib.uliege.be/2684-6500/index.php?id=219