https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Thu, 18 Jun 2026 05:18:20 GMT 2026-06-18T05:18:20Z http://hdl.handle.net/10985/11675 Characterization of identification errors and uses in localization of poor modal correlation MARTIN, Guillaume; BALMES, Etienne; CHANCELIER, Thierry While modal identification is a mature subject, very few studies address the characterization of errors associated with components of a mode shape. This is particularly important in test/analysis correlation procedures, where the Modal Assurance Criterion is used to pair modes and to localize at which sensors discrepancies occur. Poor correlation is usually attributed to modeling errors, but clearly identification errors also occur. In particular with 3D Scanning Laser Doppler Vibrometer measurement, many transfer functions are measured. As a result individual validation of each measurement cannot be performed manually in a reasonable time frame and a notable fraction of measurements is expected to be fairly noisy leading to poor identification of the associated mode shape components. The paper first addresses measurements and introduces multiple criteria. The error measures the difference between test and synthesized transfer functions around each resonance and can be used to localize poorly identified modal components. For intermediate error values, diagnostic of the origin of the error is needed. The level evaluates the transfer function amplitude in the vicinity of a given mode and can be used to eliminate sensors with low responses. A Noise Over Signal indicator, product of error and level, is then shown to be relevant to detect poorly excited modes and errors due to modal property shifts between test batches. Finally, a contribution is introduced to evaluate the visibility of a mode in each transfer. Using tests on a drum brake component, these indicators are shown to provide relevant insight into the quality of measurements. In a second part, test/analysis correlation is addressed with a focus on the localization of sources of poor mode shape correlation. The MACCo algorithm, which sorts sensors by the impact of their removal on a MAC computation, is shown to be particularly relevant. Combined with the error it avoids keeping erroneous modal components. Applied after removal of poor modal components, it provides spatial maps of poor correlation, which help localizing mode shape correlation errors and thus prepare the selection of model changes in updating procedures. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/11675 2017-01-01T00:00:00Z MARTIN, Guillaume BALMES, Etienne CHANCELIER, Thierry While modal identification is a mature subject, very few studies address the characterization of errors associated with components of a mode shape. This is particularly important in test/analysis correlation procedures, where the Modal Assurance Criterion is used to pair modes and to localize at which sensors discrepancies occur. Poor correlation is usually attributed to modeling errors, but clearly identification errors also occur. In particular with 3D Scanning Laser Doppler Vibrometer measurement, many transfer functions are measured. As a result individual validation of each measurement cannot be performed manually in a reasonable time frame and a notable fraction of measurements is expected to be fairly noisy leading to poor identification of the associated mode shape components. The paper first addresses measurements and introduces multiple criteria. The error measures the difference between test and synthesized transfer functions around each resonance and can be used to localize poorly identified modal components. For intermediate error values, diagnostic of the origin of the error is needed. The level evaluates the transfer function amplitude in the vicinity of a given mode and can be used to eliminate sensors with low responses. A Noise Over Signal indicator, product of error and level, is then shown to be relevant to detect poorly excited modes and errors due to modal property shifts between test batches. Finally, a contribution is introduced to evaluate the visibility of a mode in each transfer. Using tests on a drum brake component, these indicators are shown to provide relevant insight into the quality of measurements. In a second part, test/analysis correlation is addressed with a focus on the localization of sources of poor mode shape correlation. The MACCo algorithm, which sorts sensors by the impact of their removal on a MAC computation, is shown to be particularly relevant. Combined with the error it avoids keeping erroneous modal components. Applied after removal of poor modal components, it provides spatial maps of poor correlation, which help localizing mode shape correlation errors and thus prepare the selection of model changes in updating procedures. http://hdl.handle.net/10985/16935 MDRE: an efficient expansion tool to perform model updating from squeal measurements MARTIN, Guillaume; VERMOT DES ROCHES, Guillaume; BALMES, Etienne; CHANCELIER, Thierry In brake FEM, model updating is often needed to improve the model accuracy and well describe problematic phenomena such as the squeal. To avoid performing a full model updating which is often time consuming, the use of the Minimum Dynamic Residual Expansion method is proposed to help building the updating strategy. The procedure proposed in this paper is evaluated on a disc brake system, using experimental measurements and the nominal model as input data. From experimental squeal measurements, two shapes are extracted and expanded on the current model. The evaluation of the residual error of model shows areas where the model is wrong and guides through the definition of sensitive parameters which need to be updated. Once the model is parameterized, a model reduction strategy is proposed for further computations to be performed in a time compatible with industrial processes. A parametric study is then achieved: the expansion is computed for all the combinations of the chosen parameters. It is finally possible to navigate through the expansion results for all the parameters, evaluate the evolution of the model accuracy and extract the best combination which improves the model representability. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/16935 2019-01-01T00:00:00Z MARTIN, Guillaume VERMOT DES ROCHES, Guillaume BALMES, Etienne CHANCELIER, Thierry In brake FEM, model updating is often needed to improve the model accuracy and well describe problematic phenomena such as the squeal. To avoid performing a full model updating which is often time consuming, the use of the Minimum Dynamic Residual Expansion method is proposed to help building the updating strategy. The procedure proposed in this paper is evaluated on a disc brake system, using experimental measurements and the nominal model as input data. From experimental squeal measurements, two shapes are extracted and expanded on the current model. The evaluation of the residual error of model shows areas where the model is wrong and guides through the definition of sensitive parameters which need to be updated. Once the model is parameterized, a model reduction strategy is proposed for further computations to be performed in a time compatible with industrial processes. A parametric study is then achieved: the expansion is computed for all the combinations of the chosen parameters. It is finally possible to navigate through the expansion results for all the parameters, evaluate the evolution of the model accuracy and extract the best combination which improves the model representability. http://hdl.handle.net/10985/26071 Non-linear viscoelastic damping: designing tests needed for transient simulation of a rail track ETIENNE, BALMES; MARTIN, Guillaume; VO VAN, Olivier Viscoelastic materials are widely used in many industries for their ability to undergo large deformation and dissipate energy. Pads placed between rail and sleeper experience large deformation when the train passes. This is important for load distribution to the sleepers. They also strongly contribute to vibration damping, and thus to lowering noise emissions associated with rail/wheel contact. There is thus a need to have a model that allows transient simulation in a regime accounting for dependence of the behavior on time history including multiple time scales. The study revisits the design and exploitation of test sequences combining steps, ramps, stepped sine and sweeps in frequency and amplitude. Illustrations are given for full scale tests of rail-spleeper pads. Sun, 01 Sep 2024 00:00:00 GMT http://hdl.handle.net/10985/26071 2024-09-01T00:00:00Z ETIENNE, BALMES MARTIN, Guillaume VO VAN, Olivier Viscoelastic materials are widely used in many industries for their ability to undergo large deformation and dissipate energy. Pads placed between rail and sleeper experience large deformation when the train passes. This is important for load distribution to the sleepers. They also strongly contribute to vibration damping, and thus to lowering noise emissions associated with rail/wheel contact. There is thus a need to have a model that allows transient simulation in a regime accounting for dependence of the behavior on time history including multiple time scales. The study revisits the design and exploitation of test sequences combining steps, ramps, stepped sine and sweeps in frequency and amplitude. Illustrations are given for full scale tests of rail-spleeper pads. http://hdl.handle.net/10985/23306 A Structural Dynamics Modification Strategy based on Expanded Squeal Operational Deflection Shapes MARTIN, Guillaume; BALMES, Etienne; CHANCELIER, Thierry; THOUVIOT, Sylvain; LEMAIRE, Rémi To analyze brake squeal, measurements are performed to extract Operational Deflection Shapes (ODS) characteristic of the limit cycle. The advantage of this strategy is that the real system behavior is captured, but measurements suffer from a low spatial distribution and hidden surfaces, so that interpretation is sometimes difficult. It is even more difficult to propose system modifications from test alone. Historical Structural Dynamics Modification (SDM) techniques need mass normalized shapes which is not available from an ODS measurement. Furthermore, it is very difficult to translate mass, damping or stiffness modification between sensors into physical modifications of the real system. On the model side, FEM methodology gives access to fine geometric details, continuous field over the whole system. Simple simulation of the impact of modifications is possible, one typical strategy for squeal being to avoid unstable poles. Nevertheless, to ensure accurate predictions, test/FEM correlation must be checked and model updating may be necessary despite high cost and absence of guarantee on results. To combine both strategies, expansion techniques seek to estimate the ODS on all FEM DOF using a multi-objective optimization combining test and model errors. The high number of sensors compensates for modeling errors, while allowing imperfect test. The Minimum Dynamics Residual Expansion (MDRE) method used here, ensures that the complex ODS expanded shapes are close enough to the measured motion but have smooth, physically representative, stress field, which is mandatory for further analysis. From the expanded ODS and using the model, the two underlying real shapes are mass-orthonormalized and stiffness-orthogonalized resulting in a reduced modal model with two modes defined at all model DOFs. Sensitivity analysis is then possible and the impact of thickness modifications on frequencies is estimated. This provides a novel structural modification strategy where the parameters are thickness distributions and the objective is to separate the frequencies associated with the two shapes found by expansion of the experimental ODS. Sun, 01 May 2022 00:00:00 GMT http://hdl.handle.net/10985/23306 2022-05-01T00:00:00Z MARTIN, Guillaume BALMES, Etienne CHANCELIER, Thierry THOUVIOT, Sylvain LEMAIRE, Rémi To analyze brake squeal, measurements are performed to extract Operational Deflection Shapes (ODS) characteristic of the limit cycle. The advantage of this strategy is that the real system behavior is captured, but measurements suffer from a low spatial distribution and hidden surfaces, so that interpretation is sometimes difficult. It is even more difficult to propose system modifications from test alone. Historical Structural Dynamics Modification (SDM) techniques need mass normalized shapes which is not available from an ODS measurement. Furthermore, it is very difficult to translate mass, damping or stiffness modification between sensors into physical modifications of the real system. On the model side, FEM methodology gives access to fine geometric details, continuous field over the whole system. Simple simulation of the impact of modifications is possible, one typical strategy for squeal being to avoid unstable poles. Nevertheless, to ensure accurate predictions, test/FEM correlation must be checked and model updating may be necessary despite high cost and absence of guarantee on results. To combine both strategies, expansion techniques seek to estimate the ODS on all FEM DOF using a multi-objective optimization combining test and model errors. The high number of sensors compensates for modeling errors, while allowing imperfect test. The Minimum Dynamics Residual Expansion (MDRE) method used here, ensures that the complex ODS expanded shapes are close enough to the measured motion but have smooth, physically representative, stress field, which is mandatory for further analysis. From the expanded ODS and using the model, the two underlying real shapes are mass-orthonormalized and stiffness-orthogonalized resulting in a reduced modal model with two modes defined at all model DOFs. Sensitivity analysis is then possible and the impact of thickness modifications on frequencies is estimated. This provides a novel structural modification strategy where the parameters are thickness distributions and the objective is to separate the frequencies associated with the two shapes found by expansion of the experimental ODS. http://hdl.handle.net/10985/20775 Viscoelastic homogenization of 3D woven composites with damping validation in temperature and verification of scale separation CONEJOS, Florian; BALMES, Etienne; TRANQUART, Bastien; MARTIN, Guillaume; MONTEIRO, Eric Estimation of damping can be of great importance for turbomachines, where vibration based instabilities like flutter occur. The paper discusses a numerical method to predict the homogenized viscoelastic behavior of 3D woven composites, used in fan blades, from elementary constituent behavior. Yarn and weave microstructures are considered in a two scale homogenization. The matrix and fibers are considered homogeneous with linear viscoelastic and elastic behavior respectively. Temperature and frequency dependence of matrix properties are characterized by complex moduli. Confrontation of numerical predictions with modal damping of a modified Oberst experiment, for a temperature range of -40 to 120 °C, gives good results in terms of absolute value and trends. The homogenization is formulated using matrix operations, which enables the simple use of model reduction techniques for parametric studies on temperature and leads to energy fraction analyses useful to gain understanding of how different components of the constitutive laws contribute to damping and change with temperature. Finally, since weaving patterns have a scale of a few centimeters, that is not small compared to gradients found in the experiment, exact solutions for responses to regular volume loads are used to characterize the validity of the scale separation hypothesis as a function of wavelength. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/20775 2021-01-01T00:00:00Z CONEJOS, Florian BALMES, Etienne TRANQUART, Bastien MARTIN, Guillaume MONTEIRO, Eric Estimation of damping can be of great importance for turbomachines, where vibration based instabilities like flutter occur. The paper discusses a numerical method to predict the homogenized viscoelastic behavior of 3D woven composites, used in fan blades, from elementary constituent behavior. Yarn and weave microstructures are considered in a two scale homogenization. The matrix and fibers are considered homogeneous with linear viscoelastic and elastic behavior respectively. Temperature and frequency dependence of matrix properties are characterized by complex moduli. Confrontation of numerical predictions with modal damping of a modified Oberst experiment, for a temperature range of -40 to 120 °C, gives good results in terms of absolute value and trends. The homogenization is formulated using matrix operations, which enables the simple use of model reduction techniques for parametric studies on temperature and leads to energy fraction analyses useful to gain understanding of how different components of the constitutive laws contribute to damping and change with temperature. Finally, since weaving patterns have a scale of a few centimeters, that is not small compared to gradients found in the experiment, exact solutions for responses to regular volume loads are used to characterize the validity of the scale separation hypothesis as a function of wavelength. 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. http://hdl.handle.net/10985/21975 Bending waves focusing in arbitrary shaped plate-like structures: Study of temperature effects, development of a digital twin and of an associated neural-network based compensation procedure BENBARA, Nassim; MARTIN, Guillaume; RÉBILLAT, Marc; MECHBAL, Nazih Advanced automotive audio applications are more and more demanding with respect to the visual impact of loudspeakers while still requiring more and more channels for high quality spatial audio rendering. Removing classical heavy and large electrodynamic loudspeakers and using car interior plate-like structures driven by state of the art spatial sound algorithms appear as a promising solution to tackle both issues. However, to meet spatial audio rendering constraints, the bending waves generated within car interior plate-like structures must be focused at a given position and to a certain extent within the host structure. Theoretically, this means being able to invert in a robust manner the spatio-temporal wave propagation operator for the generated bending waves to fit a given target shape. The propagation operator inversion method considered here is the spatio-temporal inverse filtering (STIF) method based on the knowledge of the propagation operator on a regular spatial grid over the structure at a given temperature. However, in a car interior a high temperature variations exist and can adversely impact the performances of the STIF method, mainly because dynamical properties of the host structure (built up with polypropylene in most cases) largely vary within this temperature range. Even if the STIF method has already been adapted and assessed in the context of automotive audio reproduction, no study dealing with the effects of temperature on the STIF method and providing potential mitigation procedures avoiding experimental measurements at each temperature has been reported. To address that issue, the influence of temperature on the behavior of a polypropylene plate is first experimentally quantified. A model updating method is used to build a finite-element model of the plate taking into account temperature effects. This digital twin of the host-structure is then used to assess the influence of the temperature on the STIF method. A neural network based controller is finally trained and validated on the digital twin in order to compensate for the effects of temperature on STIF filters. Obtained results demonstrate that this procedure successfully allows to compensate for temperature effects on the STIF method applied to polypropylene plate with very limited experimental needs, thus paving the way through an industrial development of such approaches. Sun, 01 May 2022 00:00:00 GMT http://hdl.handle.net/10985/21975 2022-05-01T00:00:00Z BENBARA, Nassim MARTIN, Guillaume RÉBILLAT, Marc MECHBAL, Nazih Advanced automotive audio applications are more and more demanding with respect to the visual impact of loudspeakers while still requiring more and more channels for high quality spatial audio rendering. Removing classical heavy and large electrodynamic loudspeakers and using car interior plate-like structures driven by state of the art spatial sound algorithms appear as a promising solution to tackle both issues. However, to meet spatial audio rendering constraints, the bending waves generated within car interior plate-like structures must be focused at a given position and to a certain extent within the host structure. Theoretically, this means being able to invert in a robust manner the spatio-temporal wave propagation operator for the generated bending waves to fit a given target shape. The propagation operator inversion method considered here is the spatio-temporal inverse filtering (STIF) method based on the knowledge of the propagation operator on a regular spatial grid over the structure at a given temperature. However, in a car interior a high temperature variations exist and can adversely impact the performances of the STIF method, mainly because dynamical properties of the host structure (built up with polypropylene in most cases) largely vary within this temperature range. Even if the STIF method has already been adapted and assessed in the context of automotive audio reproduction, no study dealing with the effects of temperature on the STIF method and providing potential mitigation procedures avoiding experimental measurements at each temperature has been reported. To address that issue, the influence of temperature on the behavior of a polypropylene plate is first experimentally quantified. A model updating method is used to build a finite-element model of the plate taking into account temperature effects. This digital twin of the host-structure is then used to assess the influence of the temperature on the STIF method. A neural network based controller is finally trained and validated on the digital twin in order to compensate for the effects of temperature on STIF filters. Obtained results demonstrate that this procedure successfully allows to compensate for temperature effects on the STIF method applied to polypropylene plate with very limited experimental needs, thus paving the way through an industrial development of such approaches. http://hdl.handle.net/10985/8592 Improved Modal Assurance Criterion using a quantification of identification errors per mode/sensor MARTIN, Guillaume; BALMES, Etienne; CHANCELIER, Thierry Scanning laser vibrometer measurements generate detailed maps of modal characteristics in normal or 3D directions. Since many points are measured, individual validation of cannot be performed manually in a reasonable time frame and a notable fraction of measurements is expected to be fairly noisy. The key new notion of the paper is a quantification of identification error and level of contribution for each mode and each sensor based on the comparison of measured and synthesized transfers around each resonance. These criteria are shown to allow efficient analysis of the validity of large measurement sets to provide an automated procedure to select sensors that should be kept for each mode. This quantification, being performed before correlation, provides a priori estimates of sources of poor correlation associated with the identification process. It thus becomes possible to provide improved Modal Assurance Criterion estimations where, for each modeshape, sensors known to be incorrectly identified can be discarded. The 3D vibrometer scan of a brake component is used to illustrate the proposed strategies. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8592 2014-01-01T00:00:00Z MARTIN, Guillaume BALMES, Etienne CHANCELIER, Thierry Scanning laser vibrometer measurements generate detailed maps of modal characteristics in normal or 3D directions. Since many points are measured, individual validation of cannot be performed manually in a reasonable time frame and a notable fraction of measurements is expected to be fairly noisy. The key new notion of the paper is a quantification of identification error and level of contribution for each mode and each sensor based on the comparison of measured and synthesized transfers around each resonance. These criteria are shown to allow efficient analysis of the validity of large measurement sets to provide an automated procedure to select sensors that should be kept for each mode. This quantification, being performed before correlation, provides a priori estimates of sources of poor correlation associated with the identification process. It thus becomes possible to provide improved Modal Assurance Criterion estimations where, for each modeshape, sensors known to be incorrectly identified can be discarded. The 3D vibrometer scan of a brake component is used to illustrate the proposed strategies. http://hdl.handle.net/10985/12794 Squeal measurement using operational deflection shape. Quality assessment and analysis improvement using FEM expansion. BALMES, Etienne; VERMOT DES ROCHES, Guillaume; CHANCELIER, Thierry; MARTIN, Guillaume In presence of squeal, Operational Deflection Shapes (ODS) are classically measured to gain understanding of brake behavior. A simple numeric example is analyzed to justify the use of time-frequency analysis and shows that two real shapes should probably dominate the response. Using measurements on a real brake, this expectation is shown to hold even in the presence of variations with wheel position as well as for reproducibility tests. For a proper relation with the model, it is desirable to also extract modes. The test campaign is used to illustrate how this can be quite difficult due to reproducibility problems. Finally, shapes characterizing the squeal event are fundamentally limited by measurable quantities. Minimum Dynamic Residual Expansion (MDRE), which estimates test motion at all FE degrees of freedom, is shown to be applicable for industrial models and gives insight of test and model imperfections. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/12794 2017-01-01T00:00:00Z BALMES, Etienne VERMOT DES ROCHES, Guillaume CHANCELIER, Thierry MARTIN, Guillaume In presence of squeal, Operational Deflection Shapes (ODS) are classically measured to gain understanding of brake behavior. A simple numeric example is analyzed to justify the use of time-frequency analysis and shows that two real shapes should probably dominate the response. Using measurements on a real brake, this expectation is shown to hold even in the presence of variations with wheel position as well as for reproducibility tests. For a proper relation with the model, it is desirable to also extract modes. The test campaign is used to illustrate how this can be quite difficult due to reproducibility problems. Finally, shapes characterizing the squeal event are fundamentally limited by measurable quantities. Minimum Dynamic Residual Expansion (MDRE), which estimates test motion at all FE degrees of freedom, is shown to be applicable for industrial models and gives insight of test and model imperfections. http://hdl.handle.net/10985/23307 Expansion in structural dynamics : a perspective gained from success and errors in test/FEM twin building BALMES, Etienne; MARTIN, Guillaume; VERMOT DES ROCHES, Guillaume; CHANCELIER, Thierry; THOUVIOT, Sylvain Since tests only provide measurements at sensors, it is interesting to use models to estimate the response at all degree of freedom, correct measurement errors and possibly allow updating of model parameters. The paper gives an integrated perspective on methods developed by the control and structural dynamics communities and in particular methods seeking a trade-off between test and model error. The case of a measured brake squeal limit cycle is used to illustrate implementation details found to be important. Sun, 01 May 2022 00:00:00 GMT http://hdl.handle.net/10985/23307 2022-05-01T00:00:00Z BALMES, Etienne MARTIN, Guillaume VERMOT DES ROCHES, Guillaume CHANCELIER, Thierry THOUVIOT, Sylvain Since tests only provide measurements at sensors, it is interesting to use models to estimate the response at all degree of freedom, correct measurement errors and possibly allow updating of model parameters. The paper gives an integrated perspective on methods developed by the control and structural dynamics communities and in particular methods seeking a trade-off between test and model error. The case of a measured brake squeal limit cycle is used to illustrate implementation details found to be important.