AI Article Synopsis
- The paper reveals that conventional triangulation methods are unreliable for determining impact points in isotropic plates due to challenges in accurately measuring signal arrival times and the dispersive nature of Lamb waves.
- An alternative optimization-based approach is introduced to improve location accuracy for both isotropic and anisotropic plates, with a specific formulation for the general anisotropic case.
- Experiments conducted on an aluminum plate compare impact point predictions from the triangulation technique with the new method, also examining how predictions differ when accounting for plate anisotropy.
Article Abstract
It is shown in this paper that the conventional triangulation technique is not very reliable for locating the impact point even in isotropic plates when the sensors are placed close to the point of strike for two reasons: First, it is difficult to pinpoint the exact time of arrival of the signal and, second, the Lamb modes in a plate are dispersive. Dispersive signals attenuate differently at various frequencies and propagate with different speeds causing distortions in the received signals, and thus introduce error in the time of flight measurement. The triangulation technique assumes that wave speeds in all directions are the same, which is not true for anisotropic plates. Here an alternative approach based on an optimization scheme is proposed to locate the point of impact in isotropic and anisotropic plates. A formulation is presented for the general anisotropic case. Experiments are carried out with an aluminum plate by dropping balls on the plate and picking up acoustic signals at different locations. The impact points predicted by the conventional triangulation technique and the proposed modified method are compared for this isotropic plate. Then it is investigated how the prediction would change if the plate is assumed to have some anisotropy.
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| http://dx.doi.org/10.1121/1.2775322 | DOI Listing |
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