Table 5 Summary of available OMA techniques
From: An Overview: The Application of Vibration-Based Techniques in Bridge Structural Health Monitoring
Method | Type | Advantages | Limitation |
|---|---|---|---|
PP | Frequency domain | The simplest, most straightforward, and least computationally expensive approach | Inaccurate for a system with closely spaced modes, as in most of the cases in real structures |
FDD | Frequency-domain | Natural frequencies and closely spaced mode shapes can be accurately identified | The precision of the estimated natural frequency is restricted by the FFT resolution Damping ratios cannot be calculated |
EFDD | Frequency-domain | Method of processing that is simple to use and quick Can determine damping ratios, mode shapes, and natural frequencies more accurately than FDD | Exact estimation of modal damping remains a challenge, which may often lead to biased estimates |
NExT | Time-domain | Provides a solid foundation for extending EMA methods in OMA | The nature of the data in OMA is stochastic, but the framework in NExT techniques is deterministic |
ARMA | Time-domain | Output measurements can be used directly | A computationally demanding method |
SSI | Time-domain | High level of parameter estimate accuracy as well as a high level of computing efficiency compared to other OMA techniques | A mathematically complex method |