Reducing the impact of measurement errors in FRF-based substructure decoupling using a modal model

Peeters, Pepijn; Manzato, Simone; Tamarozzi, Tommaso; Desmet, Wim

doi:10.1016/j.ymssp.2017.06.020

Cited by 18 publications

(14 citation statements)

References 16 publications

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“…Structural dynamic responses of a built-up structure are highly dependent on the properties of structural components and joints [1]. The responses are often investigated and evaluated using FRFs due to overwhelming data [2][3][4]. FRFs can be obtained from the structure analytically and experimentally [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the rotational FRF (RFRF) could be indirectly obtained using an attachment of T-block [8,12]. The FRFs measured at the T-block was then decoupled from the system to obtain the rotational FRFof the test structure [4]. Another alternate method used to estimate RFRs is using X-block attachment with three translational accelerometers.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Estimating Rotational Frequency Response Function Using Mode Expansion and Frequency Response Function Synthesis Method

Mirza¹,

Rani²,

Yunus³

et al. 2021

IJAME

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The rotational frequency response function (RFRF) plays a crucial role in increasing the accuracy of the calculated results of the frequency-based substructuring method. However, RFRFs are often omitted due to the difficulties in the measurement process and limitations of the equipment. This paper presents a scheme of estimating the rotational FRF of an irregular plate structure using the FE model reduction and expansion method. The reduced FE model was introduced using the improved reduction system (IRS) and expanded to the experimental modal model (EMA model) using the system reduction and the expansion (SEREP) method. The FRF expanded method was then employed to derive the translational and rotational FRFs from the expanded EMA model. The accuracy of the expanded FRFs was evaluated with the EMA model of the irregular plate. It was found that the translational and rotational FRFs estimated from the proposed scheme were in good agreement with the EMA counterparts. Furthermore, the patterns of the estimated RFRFs were well correlated with the EMA RFRFs. This work shows that the proposed scheme may offer an attractive alternative way of accurately determining the RFRs of complex structures or structural components.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Estimating Rotational Frequency Response Function Using Mode Expansion and Frequency Response Function Synthesis Method

Mirza¹,

Rani²,

Yunus³

et al. 2021

IJAME

View full text Add to dashboard Cite

show abstract

“…The essential issue lies in the FBS method used in the preparation of experimental work as highlighted in [15]. The basic theory of the FBS method is that the FRF of all degrees of freedom (DOFs) at the interface connection is required for the coupling process [16] but measuring accurately all the translational and rotational FRFs at the interfaces of substructures is very challenging and problematic [17,18]. A few approaches have been proposed to improve the FBS method such as the transmission simulator method [19], the variability improvement of key inaccurate node groups (VIKING) [20], inverse dynamic substructuring [21] and modal expansion methods [22,23].…”

Section: Introductionmentioning

confidence: 99%

Alternative scheme for frequency response function measurement of experimental-analytical dynamic substructuring

Mirza

Rani

Yunus

et al. 2019

JMES

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The accuracy of the predicted dynamic behaviour of an assembled structure using the frequency based substructuring (FBS) method is often found to be diverged from the experimental counterparts. The divergence which has become the paramount concern and major issue for structural dynamicists is because of the unreliable experimental FRF data of the interfaces of substructures, arising from the limited resources of appropriate excitation points and accelerometer attachments in the vicinity of the interfaces. This paper presents an alternative scheme for FRF measurement of the experimental FRF data of substructures. In this study, an assembled structure consisting of two substructures were used, namely substructure A (Finite element model) and substructure B (Experimental model). The FE model of substructure A was constructed by using 3D elements and the FRFs were derived via the FRF synthesis method. Specially customised bolts were used to allow the attachment of accelerometers and excitation to be made at the interfaces of substructure B, and the FRFs were measured by using impact testing. Both substructures A and B were then coupled by using the FBS method and the coupled FRF was validated with the measured FRF counterparts. This work revealed that the proposed scheme with specially customized bolts has led to a significant enhancement and improvement in the FBS predicted results.

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“…In structural dynamics, the dynamic behaviour of a structure which consists of several components or substructures can be efficiently and economically calculated by using dynamic substructuring method [1,2]. This method allows a built-up structure to be dissembled into several substructures and analysing analysis of the dynamic behaviour of the substructures can be done individually.…”

Section: Introductionmentioning

confidence: 99%

“… (1),(2). and(3), the partitions matrix of subsystems A and B is derived to form the whole coupled system FRF matrix.…”

mentioning

confidence: 99%

Frequency Based Substructuring for Structure with Double Bolted Joints: A Case Study

Mirza

Rani

Yunus

et al. 2019

IJAME

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Adopting dynamic substructuring schemes is a common practice in the field of structural dynamics, where the dynamic behaviour of a structure is predicted by combining the multiple subsystems that are analysed individually. This paper investigated the dynamic behaviour of a structure with doubled bolted joints using the frequency based substructuring (FBS) method. In the attempt, the substructures were combined with the frequency domain that can be numerically derived or experimentally measured. However, the applicability of this method suffered from several issues where most of them were related to the frequency response function (FRF) of the rotational degree of freedom (DOF) at the subsystem’s interface. In some cases, the system’s interface vibrated in the rotary motion of certain modes, for instance, a car side rear view mirror. Therefore, excluding the rotational FRF during the coupling process could lead to a completely different result. This paper presents the use of the FBS method for a structure with double bolted joints by using the equivalent multipoint constraint (EMPC) method through which rotational DOFs can be completely neglected. The actual tested structure for this study was an assembled structure consisting of two substructures: a simple beam and an irregular plate steel structure. The FRFs of both substructures were derived from using the FRF synthesis from finite element models and combined together via the FBS method. This study reveals that the use of the FBS method with the EMPC method for a structure double bolted joints has led to very promising results.

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Reducing the impact of measurement errors in FRF-based substructure decoupling using a modal model

Cited by 18 publications

References 16 publications

Estimating Rotational Frequency Response Function Using Mode Expansion and Frequency Response Function Synthesis Method

Estimating Rotational Frequency Response Function Using Mode Expansion and Frequency Response Function Synthesis Method

Alternative scheme for frequency response function measurement of experimental-analytical dynamic substructuring

Frequency Based Substructuring for Structure with Double Bolted Joints: A Case Study

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