Composite structures are susceptible to sudden failures due their complex modes of failure. One of these modes is delamination, the detachment of the layers due to the rupture in the fiber-matrix interface. To avoid catastrophic failures, several Structural Health Monitoring techniques are employed. Damage indexes based on wavelet transform techniques are vastly explored and provide prominent results. However, they depend on user experience and are usually formulated by trial and error. The present study proposes a damage index to identify delaminations in a laminated composite beam, yet, the development is based on a well-defined methodology. The proposed damage index is composed of a weighted sum of discrete wavelet transform detail coefficients, obtained by applying the transform to the mode shapes of the structure. Mode shapes were obtained numerically and damage was simulated with a stiffness reduction in some elements of the model. A mixture design analysis and a multiobjective optimization were used for tuning the damage index parameters, which improved the accuracy of the damage index in 100% of the evaluated cases. The proposed method was capable of locating damage with substantial performance along the beam length and has the advantageous characteristic of being a no-baseline method.

复合结构由于其复杂的失效模式而容易受到突然失效的影响。其中一种模式是分层，即由于纤维-基质界面破裂而导致的层分离。为避免灾难性故障，采用了多种结构健康监测技术。基于小波变换技术的损伤指数被广泛探索并提供了显着的结果。但是，它们取决于用户体验，通常是通过反复试验来制定的。本研究提出了一种损伤指数来识别层压复合梁中的分层，然而，该开发基于明确定义的方法。建议的损伤指数由离散小波变换细节系数的加权和组成，通过将变换应用于结构的模式形状而获得。模态振型是通过数值方法获得的，并通过模型的某些元素的刚度降低来模拟损坏。混合设计分析和多目标优化用于调整损伤指标参数，在100%的评估案例中提高了损伤指标的准确性。所提出的方法能够沿梁长度定位具有显着性能的损伤，并且具有作为无基线方法的优点。