# US 2025/0060337 A1 · Method and system for damage localization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0060337 A1 - Document ID: US20250060337A1 - Status: Published application - Kind: A1 - Application number: 18/791,220 - Filed: 2024-07-31 - Published: 2025-02-20 - Earliest claimed: 2023-08-17 - Assignees: Tata Consultancy Services Limited - Applicants: Tata Consultancy Services Limited - Inventors: SUBHADEEP BASU; ARIJIT SINHARAY; TAPAS CHAKRAVARTY; SUPRIYA GAIN; ARPAN PAL - Web page: https://patentgrep.com/patent/US20250060337A1 ## CPC - G01N 29/041: {on the surface of the material, e.g. using Lamb, Rayleigh or shear waves} - G01N 29/043: {in the interior, e.g. by shear waves} - G01N 29/069: {Defect imaging, localisation and sizing using, e.g. time of flight diffraction [TOFD], synthetic aperture focusing technique [SAFT], Amplituden-Laufzeit-Ortskurven [ALOK] technique} - G01N 29/2437: {Piezoelectric probes} - G01N 29/343: {pulse waves, e.g. particular sequence of pulses, bursts} - G01N 29/4472: {Mathematical theories or simulation} - G01N 29/449: {Statistical methods not provided for in G01N29/4409, e.g. averaging, smoothing and interpolation} - G01N 2291/0231: Composite or layered materials - G01N 2291/0258: Structural degradation, e.g. fatigue of composites, ageing of oils - G01N 2291/0289: Internal structure, e.g. defects, grain size, texture - G01N 2291/103: one emitter, two or more receivers - G01N 2291/106: one or more transducer arrays - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract This disclosure relates generally to a method and system for damage localization on surfaces made of composites and metals. State-of-the-art methods for ultrasonic guided wave-based damage localization provide a reasonable accuracy. However, accuracy of prediction based on minimum number of observations is not yet achieved. The disclosed method provides damage localization by capturing response to the ultrasonic tone burst transmitted by a plurality of active piezoelectric sensors. The disclosed method provides a modified RAPID algorithm that considers an attenuation of the ultrasonic guided waves and factors energy of transmitted and received signals while predicting damage location. The method provides iterative grid search reduction mechanism to predict damage on the surfaces made of composites and metals. ## Claims ### Claim 1 A processor implemented method for localizing damage, the method comprising: transmitting, via a one or more hardware processors, a plurality of active piezoelectric sensors among a plurality of piezoelectric sensors controlled by one or more hardware processors, an ultrasonic tone burst on a damaged surface, and on a damage-free surface, wherein the plurality of piezoelectric sensors is arranged to form a grid structure; receiving, via the one or more hardware processors, a plurality of active piezoelectric sensors among the plurality of piezoelectric sensors controlled by one or more hardware processors, an ultrasonic tone burst response from i) the damaged surface to create a sample dataset, and ii) the damage-free surface to create a reference dataset; applying, via the one or more hardware processors, to the sample dataset and the reference dataset, a reconstruction algorithm for probabilistic inspection of defects (RAPID) to identify an initial probabilistic damage location, a centroid of the initial probabilistic damage location, a quadrant of the initial probabilistic damage location and a first set of active piezoelectric sensors among a plurality of piezo electric crystals surrounding the initial probabilistic damage location, wherein the initial probabilistic damage location is obtained by calculating a signal dissimilarity coefficient (SDC) based on dissimilarity between i) a first received signal, representing a response received by first piezoelectric sensor of the grid acting as a receiver (Rx) to the ultrasonic tone burst transmitted from a second piezoelectric sensor of the grid acting as a transmitter (Tx) positioned on the damage free surface, wherein the receiver (Rx) and the transmitter (Tx) forms a Tx-Rx path, and ii) a second received signal, representing a response received by the first piezoelectric sensor acting as the receiver (Rx) to the ultrasonic tone burst transmitted from the second piezoelectric sensor acting as the transmitter (Tx) positioned on the damaged surface, and wherein a second set of piezoelectric sensors from among the first set of piezoelectric sensors surrounding the centroid of the first damage location forms a reduced grid; estimating, via the one or more hardware processors, a size of the reduced grid; iteratively calculating, via the one or more hardware processors, a ratio of received signal energy of Tx-Rx paths of damaged surface and received signal energy of Tx-Rx paths of damage free surface until the reduced grid size is greater than a pre-defined grid size, wherein the active piezoelectric sensors of the reduced grid transmitting the ultrasonic tone burst (Tx) and the plurality of active piezoelectric sensors of the reduced grid receiving the ultrasonic tone burst response (Rx) forms a Tx-Rx path; applying iteratively, via the one or more hardware processors, a modified RAPID (M-RAPID) into the reduced grid to identify a plurality of subsequent probabilistic damage locations, one or more quadrants of the subsequent probabilistic damage locations and a third set of piezoelectric sensors within the second set of piezoelectric sensors surrounding each of the subsequent probabilistic damage locations, wherein the M-RAPID factors the ratio of the received signal energy of the Tx-Rx path of damaged surface and the received signal energy of the Tx-Rx path of damage free surface while estimating damage in the reduced grid; and averaging, via the one or more hardware processors, the subsequent probabilistic damage locations obtained by iterative application of the M-RAPID on the reduced grid to estimate an actual place of damage. ### Claim 2 (depends on 1) The method of claim 1, wherein the active piezoelectric sensors from the plurality of the piezoelectric sensors actively contribute as the transmitter and the receiver to form the Tx-Rx paths in the damaged surface and the damage free surface. ### Claim 3 (depends on 1) The method of claim 1, wherein at least four active piezoelectric sensors among the plurality of piezoelectric sensors are required for receiving ultra tone burst response in the damaged surface and the damage free surface. ### Claim 4 (depends on 1) The method of claim 1, wherein a subset of piezoelectric sensors among the plurality of piezoelectric sensors placed at first positions of the grid transmit a 5-cycle ultrasonic tone burst and the remaining piezoelectric sensors receive the response of the ultrasonic tone burst, and in successive iteration a piezoelectric sensor placed next to the piezoelectric sensor placed at first position transmits the 5-cycle ultrasonic tone burst and rest other piezoelectric sensors receives the response of the ultrasonic tone burst; the cycle continues until all piezoelectric sensors act as the transmitter. ### Claim 5 (depends on 1) The method of claim 1, wherein the pre-defined grid is a square grid with each side of the square grid equal to the wavelength of the signal transmitted by the plurality of piezoelectric sensors. ### Claim 6 (depends on 1) The method of claim 1, wherein the method of localizing damage is applicable for damage localization on surfaces made of composite sheets and metals. ### Claim 7 A system, comprising: a memory storing instructions; one or more communication interfaces; and one or more hardware processors coupled to the memory via the one or more communication interfaces, wherein the one or more hardware processors are configured by the instructions to: transmit a plurality of active piezoelectric sensors among a plurality of piezoelectric sensors controlled by one or more hardware processors, an ultrasonic tone burst on a damaged surface, and on a damage-free surface, wherein the plurality of piezoelectric sensors is arranged to form a grid structure; receive the plurality of active piezoelectric sensors among the plurality of piezoelectric sensors controlled by one or more hardware processors, an ultrasonic tone burst response from i) the damaged surface to create a sample dataset, and ii) the damage-free surface to create a reference dataset; apply to the sample dataset and the reference dataset, a reconstruction algorithm for probabilistic inspection of defects (RAPID) to identify an initial probabilistic damage location, a centroid of the initial probabilistic damage location, a quadrant of the initial probabilistic damage location and a first set of active piezoelectric sensors among the plurality of piezo electric crystals surrounding the initial probabilistic damage location, wherein the initial probabilistic damage location is obtained by calculating a signal dissimilarity coefficient (SDC) based on dissimilarity between i) a first received signal, representing a response received by a first piezoelectric sensor of the grid acting as a receiver (Rx) to the ultrasonic tone burst transmitted from a second piezoelectric sensor of the grid acting as a transmitter (Tx) positioned on the damage free surface, wherein the receiver (Rx) and the transmitter (Tx) forms a Tx-Rx path, and ii) a second received signal, representing a response received by the first piezoelectric sensor acting as the receiver (Rx) to the ultrasonic tone burst transmitted from the second piezoelectric sensor acting as the transmitter (Tx) positioned on the damaged surface, and wherein a second set of piezoelectric sensors from among the first set of piezoelectric sensors surrounding the centroid of the first damage location forms a reduced grid; estimate a size of the reduced grid; iteratively calculate a ratio of received signal energy of Tx-Rx paths of damaged surface and received signal energy of Tx-Rx paths of damage free surface until the reduced grid size is greater than a pre-defined grid size, wherein the active piezoelectric sensors of the reduced grid transmitting the ultrasonic tone burst (Tx) and the plurality of active piezoelectric sensors of the reduced grid receiving the ultrasonic tone burst response (Rx) forms a Tx-Rx path; apply iteratively a modified RAPID (M-RAPID) into the reduced grid to identify a plurality of subsequent probabilistic damage locations, one or more quadrants of the subsequent probabilistic damage locations and a third set of piezoelectric sensors within the second set of piezoelectric sensors surrounding each of the subsequent probabilistic damage locations, wherein the M-RAPID factors the ratio of the received signal energy of the Tx-Rx path of damaged surface and the received signal energy of the Tx-Rx path of damage free surface while estimating damage in the reduced grid; and average the subsequent probabilistic damage locations obtained by iterative application of the M-RAPID on the reduced grid to estimate an actual place of damage. ### Claim 8 (depends on 7) The system of claim 7, wherein the active piezoelectric sensors among the piezoelectric sensors actively contributing as the transmitter and the receiver to form the Tx-Rx paths in the damaged surface and the damage free surface. ### Claim 9 (depends on 7) The system of claim 7, wherein at least four active piezoelectric sensors among the plurality of piezoelectric sensors are required for receiving the ultra-tone burst response in the damaged surface and the damage free surface. ### Claim 10 (depends on 7) The system of claim 7, wherein a subset of piezoelectric sensors among the plurality of piezoelectric sensors placed at first positions of the grid transmit a 5-cycle ultrasonic tone burst and remaining piezoelectric sensors receive the response of the ultrasonic tone burst, and in successive iteration a piezoelectric sensor placed next to the piezoelectric sensor placed at first position transmits the 5-cycle ultrasonic tone burst and rest other piezoelectric sensors receives the response of the ultrasonic tone burst; the cycle continues until all piezoelectric sensors act as the transmitter. ### Claim 11 (depends on 7) The system of claim 7, wherein the pre-defined grid is a square grid with each side of the square grid equal to the wavelength of the signal transmitted by the piezoelectric sensors. ### Claim 12 (depends on 7) The system of claim 7, wherein the system of localizing damage is applicable for damage localization on surfaces made of composite sheets and metals. ### Claim 13 One or more non-transitory machine-readable information storage mediums comprising one or more instructions which when executed by one or more hardware processors cause: transmitting, via a plurality of active piezoelectric sensors among a plurality of piezoelectric sensors controlled by one or more hardware processors, an ultrasonic tone burst on a damaged surface, and on a damage-free surface, wherein the plurality of piezoelectric sensors is arranged to form a grid structure; receiving the plurality of active piezoelectric sensors among the plurality of piezoelectric sensors controlled by one or more hardware processors, an ultrasonic tone burst response from i) the damaged surface to create a sample dataset, and ii) the damage-free surface to create a reference dataset; applying to the sample dataset and the reference dataset, a reconstruction algorithm for probabilistic inspection of defects (RAPID) to identify an initial probabilistic damage location, a centroid of the initial probabilistic damage location, a quadrant of the initial probabilistic damage location and a first set of active piezoelectric sensors among the plurality of piezo electric crystals surrounding the initial probabilistic damage location, wherein the initial probabilistic damage location is obtained by calculating a signal dissimilarity coefficient (SDC) based on dissimilarity between i) a first received signal, representing a response received by a first piezoelectric sensor of the grid acting as a receiver (Rx) to the ultrasonic tone burst transmitted from a second piezoelectric sensor of the grid acting as a transmitter (Tx) positioned on the damage free surface, wherein the receiver (Rx) and the transmitter (Tx) forms a Tx-Rx path, and ii) a second received signal, representing a response received by the first piezoelectric sensor acting as the receiver (Rx) to the ultrasonic tone burst transmitted from the second piezoelectric sensor acting as the transmitter (Tx) positioned on the damaged surface, and wherein a second set of piezoelectric sensors from among the first set of piezoelectric sensors surrounding the centroid of the first damage location forms a reduced grid; estimating a size of the reduced grid; iteratively calculating a ratio of received signal energy of Tx-Rx paths of damaged surface and received signal energy of Tx-Rx paths of damage free surface until the reduced grid size is greater than a pre-defined grid size, wherein the active piezoelectric sensors of the reduced grid transmitting the ultrasonic tone burst (Tx) and the plurality of active piezoelectric sensors of the reduced grid receiving the ultrasonic tone burst response (Rx) forms a Tx-Rx path; applying iteratively a modified RAPID (M-RAPID) into the reduced grid to identify a plurality of subsequent probabilistic damage locations, one or more quadrants of the subsequent probabilistic damage locations and a third set of piezoelectric sensors within the second set of piezoelectric sensors surrounding each of the subsequent probabilistic damage locations, wherein the M-RAPID factors the ratio of the received signal energy of the Tx-Rx path of damaged surface and the received signal energy of the Tx-Rx path of damage free surface while estimating damage in the reduced grid; and averaging the subsequent probabilistic damage locations obtained by iterative application of the M-RAPID on the reduced grid to estimate an actual place of damage. ### Claim 14 (depends on 13) The one or more non-transitory machine-readable information storage mediums of claim 13, wherein the active piezoelectric sensors among the piezoelectric sensors actively contributing as the transmitter and the receiver to form the Tx-Rx paths in the damaged surface and the damage free surface. ### Claim 15 (depends on 13) The one or more non-transitory machine-readable information storage mediums of claim 13, wherein at least four active piezoelectric sensors among the plurality of piezoelectric sensors are required for receiving the ultra-tone burst response in the damaged surface and the damage free surface. ### Claim 16 (depends on 13) The one or more non-transitory machine-readable information storage mediums of claim 13, wherein a subset of piezoelectric sensors among the plurality of piezoelectric sensors placed at first positions of the grid transmit a 5-cycle ultrasonic tone burst and remaining piezoelectric sensors receive the response of the ultrasonic tone burst, and in successive iteration a piezoelectric sensor placed next to the piezoelectric sensor placed at first position transmits the 5-cycle ultrasonic tone burst and rest other piezoelectric sensors receives the response of the ultrasonic tone burst; the cycle continues until all piezoelectric sensors act as the transmitter. ### Claim 17 (depends on 13) The one or more non-transitory machine-readable information storage mediums of claim 13, wherein the pre-defined grid is a square grid with each side of the square grid equal to the wavelength of the signal transmitted by the piezoelectric sensors. ### Claim 18 (depends on 13) The one or more non-transitory machine-readable information storage mediums of claim 13, wherein the system of localizing damage is applicable for damage localization on surfaces made of composite sheets and metals.