https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Wed, 16 Sep 2026 19:19:20 GMT 2026-09-16T19:19:20Z http://hdl.handle.net/10985/23312 A time varying system perspective on rubber mount tests MALACRIDA ALVES, Guilherme; BALMES, Etienne Rubber tests typically only consider the first harmonic of responses and thus ignore additional information about variation of properties during a cycle. The Payne effect is then only described as a decrease of modulus with amplitude. An harmonic modulation is introduced as a novel way to look at the classical harmonic balance characterization of periodic signals in an effort to answer the question of when in the period is the system close to being linear ? In the case of enforced displacement tests, the harmonic modulation of force signals corresponds to an instant material stiffness or instant modulus. Sine test results are thus interpreted as trajectories in a complex modulus / strain plane that are much more discriminating than the traditional representation as a complex modulus and gives indication of coupling between hyperelastic, hysteretic and viscoelastic behaviors. This new interpretation of classical results is shown to be relevant as a correlation tool and a constitutive model for rubber is validated in its ability to reproduce the instant modulus behavior in a wide range of cases. Thu, 01 Sep 2022 00:00:00 GMT http://hdl.handle.net/10985/23312 2022-09-01T00:00:00Z MALACRIDA ALVES, Guilherme BALMES, Etienne Rubber tests typically only consider the first harmonic of responses and thus ignore additional information about variation of properties during a cycle. The Payne effect is then only described as a decrease of modulus with amplitude. An harmonic modulation is introduced as a novel way to look at the classical harmonic balance characterization of periodic signals in an effort to answer the question of when in the period is the system close to being linear ? In the case of enforced displacement tests, the harmonic modulation of force signals corresponds to an instant material stiffness or instant modulus. Sine test results are thus interpreted as trajectories in a complex modulus / strain plane that are much more discriminating than the traditional representation as a complex modulus and gives indication of coupling between hyperelastic, hysteretic and viscoelastic behaviors. This new interpretation of classical results is shown to be relevant as a correlation tool and a constitutive model for rubber is validated in its ability to reproduce the instant modulus behavior in a wide range of cases. http://hdl.handle.net/10985/26085 Squeal occurrence classification using a harmonic balance vector signal model ETIENNE, BALMES; MARTIN, Guillaume; MALACRIDA ALVES, Guilherme; VERMOT DES ROCHES, Guillaume Brake squeal is an instability that generates self-excited limit cycles that, in real experiments, vary with time and operating conditions. To analyze test results, it is proposed to use a Harmonic Balance Vector (HBV) signal model, that combines the space-time decomposition of the Harmonic Balance Method, where spatial distribution of each harmonic is described by a complex vector and frequency is common to all sensors, with analytic signal methodologies, where quantities are assumed to be slowly varying in time. Synchronous demodulation and principal coordinate definitions are combined in a multistep algorithm that provides an HBV estimation. % On an industrial brake test matrix, the method is shown to be robustly applicable. The HBV signal being slowly varying, sub-sampling reduces the volume of test data by two orders of magnitude. Limit cycle frequency, amplitude and shapes can thus be added to the parallel coordinates containing operating parameters: pressure, velocity, temperature, torque, disk position, disk/bracket distance, ... This opens a path to a range of analyzes otherwise difficult to perform. Classification of occurrences is first discussed showing pressure and amplitude dependence. The effect of amplitude on both frequency and shape is then demonstrated. The entry and exit of instability when parameters change are then analyzed by proposing a transient root locus built from test. Thus squeal test results are related to the classical complex eigenvalue analysis. Intermittent growth/decay events are shown to be correlated with wheel position. Furthermore, distance measurements indicate that disk shape variations of a few microns play a clear parametric role. Parametric testing and clustering are then used to map the instability region and its edges. Pressure is shown to have an effect dominating other variations. Prospective uses of these results to combine test results and finite element models are discussed last. Sun, 26 Jan 2025 00:00:00 GMT http://hdl.handle.net/10985/26085 2025-01-26T00:00:00Z ETIENNE, BALMES MARTIN, Guillaume MALACRIDA ALVES, Guilherme VERMOT DES ROCHES, Guillaume Brake squeal is an instability that generates self-excited limit cycles that, in real experiments, vary with time and operating conditions. To analyze test results, it is proposed to use a Harmonic Balance Vector (HBV) signal model, that combines the space-time decomposition of the Harmonic Balance Method, where spatial distribution of each harmonic is described by a complex vector and frequency is common to all sensors, with analytic signal methodologies, where quantities are assumed to be slowly varying in time. Synchronous demodulation and principal coordinate definitions are combined in a multistep algorithm that provides an HBV estimation. % On an industrial brake test matrix, the method is shown to be robustly applicable. The HBV signal being slowly varying, sub-sampling reduces the volume of test data by two orders of magnitude. Limit cycle frequency, amplitude and shapes can thus be added to the parallel coordinates containing operating parameters: pressure, velocity, temperature, torque, disk position, disk/bracket distance, ... This opens a path to a range of analyzes otherwise difficult to perform. Classification of occurrences is first discussed showing pressure and amplitude dependence. The effect of amplitude on both frequency and shape is then demonstrated. The entry and exit of instability when parameters change are then analyzed by proposing a transient root locus built from test. Thus squeal test results are related to the classical complex eigenvalue analysis. Intermittent growth/decay events are shown to be correlated with wheel position. Furthermore, distance measurements indicate that disk shape variations of a few microns play a clear parametric role. Parametric testing and clustering are then used to map the instability region and its edges. Pressure is shown to have an effect dominating other variations. Prospective uses of these results to combine test results and finite element models are discussed last.