This study presents an experimental investigation of the recently established generalized linear sampling method (GLSM) (Pourahmadian etal 2017 Inverse Problems 33 055007) for non-destructive evaluation of damage in elastic materials. To this end, ultrasonic shear waves are generated in a prismatic slab of charcoal granite featuring a discontinuity interface induced by the three-point bending (3PB). The interaction of probing waves with the 3PB-induced damage gives rise to transient velocity responses measured on the sample’s boundary by a 3D scanning laser Doppler vibrometer. Thus obtained waveform data are then carefully processed to retrieve the associated spectra of scattered displacement fields. On deploying multifrequency sensory data, the GLSM indicators are computed and their counterparts associated with the classical linear sampling method (LSM) (Cakoni and Colton 2003 Inverse Problems 19 279–95) for comparative analysis. Verified with in situ observations, the GLSM map successfully exposes the support of hidden scatterers in the specimen with a remarkable clarity and resolution compared to its predecessor LSM. It is further shown that the GLSM remains robust for sparse and partial-aperture data inversion, thanks to its rigorous formulation. For completeness, the one-sided reconstruction by both indicators is investigated.

本研究对最近建立的广义线性采样方法 (GLSM) (Pourahmadian et al 2017 Inverse Problems 33 ) 进行了实验研究055007) 用于弹性材料损伤的无损评估。为此，在具有由三点弯曲 (3PB) 引起的不连续界面的木炭花岗岩棱柱板中产生超声波剪切波。探测波与 3PB 引起的损伤的相互作用引起了瞬态速度响应，该响应由 3D 扫描激光多普勒振动计在样品边界上测量。如此获得的波形数据然后被仔细处理以检索散射位移场的相关光谱。在部署多频感官数据时，计算 GLSM 指标及其与经典线性采样方法 (LSM)（Cakoni 和 Colton 2003逆问题 19 279-95）相关的对应物，以进行比较分析。验证与在原位观察中，GLSM 地图成功地暴露了样本中隐藏散射体的支持，与其前身 LSM 相比，具有显着的清晰度和分辨率。进一步表明，由于其严格的公式化，GLSM 对于稀疏和部分孔径数据反演保持稳健。为了完整性，研究了两个指标的片面重建。