Characterisation of structure borne sound sources from measurement in-situ

Elliott, Andrew; Moorhouse, Andy

doi:10.1121/1.2933261

Cited by 29 publications

(11 citation statements)

References 3 publications

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“…In the following, the idea of the in-situ TPA is summarized. Elliott [4] addresses the in-situ approach as source characterization technique, done by measurements on the coupled structure.…”

Section: Concept and Validation Of An Equivalent Source Description (...mentioning

confidence: 99%

Hybrid NVH modeling approach: How numerical and experimental methods complement each other

Wegerhoff,

Kamper,

Brücher

et al. 2024

EMAS

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The ever-increasing demand for shorter development times and cost savings means that important design decisions must be made at an early stage of the development process. This goal of saving time and reducing costs leads to an increased use of virtual prototypes. However, by combining the methods of simulation and testing, the idea of saving time and reducing costs can be extended even further. In addition, in some cases the accuracy of the results can be increased compared to the approach based solely on numerical models or experimental results. Depending on the task and the availability of data (to build virtual prototypes), methods (to model certain physical phenomena) and physical prototypes, the optimal approach must be chosen. In a connected world, where development processes are distributed across different companies, the availability of data and physical prototypes becomes even more critical: companies need to share product features to create system models, but may not want to share development knowledge or product design details. In the proposed talk, a combined method of measurement and numerical simulation to predict and analyze the NVH properties of an e-bike is demonstrated. In this specific case, the electric drive unit of an e-bike that is already in series production is installed virtually in a numerical model of a new e-bike prototype. The excitation and structural dynamics of the electric drive unit are derived from experiment using the method of in-situ blocked forces. This kind of source description is known from the experimental transfer path analysis. In parallel, the numerical model of the e-bike prototype is built using a bottom-up method. The vibrations of the carbon frame induced by the virtually mounted electric drive unit are analyzed. The validity of the approach is shown using experimental data. The model presented can be used for further investigation of the airborne noise excited by the electric drive unit and radiated by the frame, which will be shown in following publications.

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Section: Concept and Validation Of An Equivalent Source Description (...mentioning

confidence: 99%

Hybrid NVH modeling approach: How numerical and experimental methods complement each other

Wegerhoff,

Kamper,

Brücher

et al. 2024

EMAS

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“…F c(b) ′ (ω)α b (ω) should be identified as the imaginary excitation. Based on two sets of vibration data obtained from two sides of the coupled connection points, two formulas were developed, as shown in equations (17) and (18 Substructure A…”

Section: Eory Of a Newmentioning

confidence: 99%

“…As a consequence, several new approaches, such as operational TPA (OTPA), have been developed in the last two decades, aimed at overcoming these limitations [10][11][12][13][14][15][16][17][18][19][20]. ese methods attract some attention as they only require operational data measured at the path and reference locations under certain conditions [21].…”

Section: Introductionmentioning

confidence: 99%

Time‐Domain Substructure Transient Vibration Transfer Path Analysis Based on Time‐Varying Frequency Response Functions under Operational Excitations

Zhou

2019

Shock and Vibration

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The time-domain substructure inverse matrix method has become a popular method to detect and diagnose problems regarding vehicle noise, vibration, and harshness, especially for those impulse excitations caused by roads. However, owning to its reliance on frequency response functions (FRFs), the approach is effective only for time-invariable linear or weak nonlinear systems. This limitation prevents this method from being applied to a typical vehicle suspension substructure, which shows different nonlinear characteristics under different wheel transient loads. In this study, operational excitation was considered as a key factor and applied to calculate dynamic time-varying FRFs to perform accurate time-domain transient vibration transfer path analysis (TPA). The core idea of this novel method is to divide whole coupled substructural relationships into two parts: one involved time-invariable components; normal FRFs could be obtained through tests directly. The other involved numerical computations of the time-domain operational loads matrix and FRFs matrix in static conditions. This method focused on determining dynamic FRFs affected by operational loads, especially the severe transient ones; these loads are difficult to be considered in other classical TPA approaches, such as operational path analysis with exogenous inputs (OPAX) and operational transfer path analysis (OTPA). Experimental results showed that this new approach could overcome the limitations of the traditional time-domain substructure TPA in terms of its strict requirements within time-invariable systems. This is because in the new method, time-varying FRFs were calculated and used, which could make the FRFs at the system level directly adapt to time-varying systems from time to time. In summary, the modified method extends TPA objects studied in time-invariable systems to time-varying systems and, thus, makes a methodology and application innovation compared to traditional the time-domain substructure TPA.

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“…Although not always necessary, the inclusion of rotational DOF in a structure-borne vibration prediction has at times shown to be an essential requirement. 17 It would therefore prove advantageous if some form of extension could be provided allowing the simultaneous measurement of both the translational and rotational components of the dynamic transfer stiffness. Such an extension is provided through the application of a finite difference approximation.…”

Section: Rotational Degrees Of Freedommentioning

confidence: 99%

In situ determination of dynamic stiffness for resilient elements

Meggitt

Elliott

Moorhouse

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part C:

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An in situ method for the measurement of a resilient elements dynamic transfer stiffness is outlined and validated. Unlike current methods, the proposed in situ approach allows for the characterisation of a resilient element whilst incorporated into an assembly, and therefore under representative mounting conditions. Potential advantages of the proposed method include the simultaneous attainment of both translational and rotational transfer stiffness components over a broad frequency range without the need for any cumbersome test rigs. These rotational components are obtained via the application of a finite difference approximation. A further advantage is provided via an extension to the method allowing for the use of remote measurement positions. Such an extension allows for the possible characterisation of hard-to-reach elements, as well as the over-determination of the problem. The proposed method can thus be broken into two sub-methods: direct and remote. Preliminary results are shown for the direct method on a simple mass-isolator-mass laboratory test rig along with a more realistic beam-isolator-plate system. Validation of this method is provided for by a transmissibility prediction, in which an obtained dynamic stiffness value is used to predict the transmissibility of a separate system. Further results are presented for the remote case using a beam-isolator-plate system. In all cases the results are obtained over a substantial frequency range and are of a sufficient quality to be used as part of structure borne sound and vibration predictions.

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Characterisation of structure borne sound sources from measurement in-situ

Cited by 29 publications

References 3 publications

Hybrid NVH modeling approach: How numerical and experimental methods complement each other

Hybrid NVH modeling approach: How numerical and experimental methods complement each other

Time‐Domain Substructure Transient Vibration Transfer Path Analysis Based on Time‐Varying Frequency Response Functions under Operational Excitations

In situ determination of dynamic stiffness for resilient elements

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