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Title |
Performance Verification of a State-Space Equation-Based Digital Twin Model Using the IMD Damage Assessment Method
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Authors |
이재훈(Jae-Hoon Lee) ; 허광희(Gwang-Hee Heo) ; 전승곤(Seung-Gon Jeon) ; 김충길(Chung-gil Kim) |
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DOI |
https://doi.org/10.11112/jksmi.2026.30.3.125 |
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Keywords |
디지털 트윈; 상태공간 방정식; IMD; 교량 안전; 모델 업데이트 Digital twin; State-space equation; IMD; Bridge safety; Model update |
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Abstract |
This study developed a state-space equation-based Digital Twin (DT) model for a model cable-stayed bridge and verified its damage localization performance using the Improved Mahalanobis Distance (IMD) damage assessment method. To this end, finite element (FE) analysis and modal testing were conducted to obtain the dynamic characteristics of the target structure, and an intact-state DT model consistent with the experimental results was constructed through modal updating. Subsequently, the variations in the mass and stiffness matrices (, ) between the non-updated intact and damaged FE models were calculated and incorporated into the modal-updated intact system matrices to construct DT models for the single cable damage case (C4) and the multiple cable damage case (C3 and C5). The El-Centro earthquake record was applied to the constructed DT models as the input excitation, and the acceleration response data generated under each damage condition were analyzed using the IMD method. The damage localization performance was then evaluated based on the Upper Control Limit (UCL) exceedance ratio and the RMS values.
The results showed that, in the single damage case, sensor S4 adjacent to the damaged cable C4 exhibited the highest IMD RMS value of 1.108. In the multiple damage case, sensors S3 and S6, adjacent to the damaged cables C3 and C5, exhibited RMS values of 1.185 and 1.179, respectively, confirming a double-peak distribution corresponding to the two damage locations. In addition, the DT-based IMD assessment results showed spatial distribution patterns similar to those of the measurement-based results. These findings confirm that the state-space equation-based DT model can effectively reproduce the relative response variation patterns caused by cable damage and can be used to support damage scenario assessment and damage localization of bridge structures under limited measurement conditions.
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