Localizing small damages often requires sensors be mounted in the proximity of damage to obtain high Signal-to-Noise Ratio in system frequency response to input excitation. The proximity requirement limits the applicability of existing schemes for low-severity damage detection as an estimate of damage location may not be known a priori. In this work it is shown that spatial locality is not a fundamental impediment; multiple small damages can still be detected with high accuracy provided that the frequency range beyond the first five natural frequencies is utilized in the Frequency response functions (FRF) curvature method. The proposed method presented in this paper applies sensitivity analysis to systematically unearth frequency ranges capable of elevating damage index peak at correct damage locations. It is a baseline-free method that employs a smoothing polynomial to emulate reference curvatures for the undamaged structure. Numerical simulation of steel-beam shows that small multiple damages of severity as low as 5% can be reliably detected by including frequency range covering 5–10^th natural frequencies. The efficacy of the scheme is also experimentally validated for the same beam. It is also found that a simple noise filtration scheme such as a Gaussian moving average filter can adequately remove false peaks from the damage index profile.

定位小损伤通常需要将传感器安装在损伤附近，以在系统频率响应输入激励时获得较高的信噪比。接近性要求限制了现有方案对低严重性损坏检测的适用性，因为可能无法事先知道损坏位置的估计值 。这项工作表明，空间局部性不是根本障碍；如果在频率响应函数（FRF）曲率方法中使用了超出前五个固有频率的频率范围，则仍可以高精度地检测到多个小损伤。本文提出的方法将灵敏度分析应用于能够在正确的损伤位置提高损伤指数峰值的系统性地频范围。这是一种不使用基线的方法，该方法采用平滑多项式来模拟未损坏结构的参考曲率。的钢束中示出数值模拟该严重程度低至5％的小倍数损失可以通过包括覆盖5-10频率范围可以可靠地检测^第 自然频率。对于相同的光束，该方案的有效性也已通过实验验证。还发现，简单的噪声过滤方案（例如高斯移动平均滤波器）可以从损伤指数曲线中充分去除虚假峰。