# US 11,307,177 B2 · Ultrasonic flaw detector and ultrasonic flaw detecting method for composite material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,177 B2 - Document ID: US11307177B2 - Status: Granted - Kind: B2 - Application number: 16/467,527 - Filed: 2017-03-14 - Published: 2019-10-24 - Granted: 2022-04-19 - Earliest claimed: 2016-12-07 - Assignees: Kawasaki Jukogyo Kabushiki Kaisha - Applicants: Kawasaki Jukogyo Kabushiki Kaisha - Inventors: Takehiro Nishimura; Mitsuhiro Kamioka; Mamoru Nishio; Daisuke Watanabe; Yousuke Tsumura - Web page: https://patentgrep.com/patent/US11307177B2 ## CPC - G01N 29/4427: {with stored values, e.g. threshold values} - B61F 1/08: Details - G01N 29/043: {in the interior, e.g. by shear waves} - G01N 29/07: by measuring propagation velocity or propagation time of acoustic waves - G01N 29/265: by moving the sensor relative to a stationary material - B61F 5/30: Axle-boxes mounted for movement under spring control in vehicle or bogie underframes {(B61F5/36 takes precedence over B61F5/305 - B61F5/34)} - G01N 2291/0231: Composite or layered materials - G01N 2291/0289: Internal structure, e.g. defects, grain size, texture - G01N 2291/044: Internal reflections (echoes), e.g. on walls or defects - G01N 2291/101: one transducer - G01N 2291/269: Various geometry objects - G01N 2291/2694: Wings or other aircraft parts - 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) - B61F: RAIL VEHICLE SUSPENSIONS, e.g. UNDERFRAMES, BOGIES OR ARRANGEMENTS OF WHEEL AXLES; RAIL VEHICLES FOR USE ON TRACKS OF DIFFERENT WIDTH; PREVENTING DERAILING OF RAIL VEHICLES; WHEEL GUARDS, OBSTRUCTION REMOVERS OR THE LIKE FOR RAIL VEHICLES (for vehicles in general B60; axles or wheels B60B; vehicle tyres B60C) ## Abstract An ultrasonic flaw detector for a composite material constituted by a plurality of materials which are different in physical properties from one another includes: a section specifier configured to specify first and second sections of an RF signal of a reflected wave of an ultrasonic wave with which the composite material is irradiated, a material reflected wave being possibly generated in the first section, an interface reflected wave being possibly generated in the second section; a material flaw determiner configured to determine whether or not a value of the RF signal exceeds a positive first threshold in the first section; and an interface flaw determiner configured to determine whether or not the value of the RF signal falls below a negative second threshold in the second section. ## Claims ### Claim 1 An ultrasonic flaw detector for a composite material, the composite material including a first material made of CFRP, a second material made of GFRP, and an interface disposed between the first material and the second material, each of the first material, the second material, and the interface having different physical properties from one another, the composite material formed by laminating the first material and the second material, the ultrasonic flaw detector comprising: a section specifier configured to specify first and second sections of an RF signal of a reflected wave of an ultrasonic wave with which the composite material is irradiated, a material reflected wave being generated in the first section, an interface reflected wave being generated in the second section, the interface reflected wave having a positive peak and a negative peak when an interface flaw exists at the interface; a material flaw determiner being configured to determine whether or not a material flaw exists by determining whether or not a value of the RF signal exceeds a positive first threshold in the first section; and an interface flaw determiner being configured to determine whether or not the interface flaw exists only by determining whether or not the value of the RF signal falls below a negative second threshold in the second section, the negative second threshold being a negative value less than 0, wherein the ultrasonic flaw detector is configured to cause an ultrasonic transmitter to irradiate the composite material from a first material side of the composite material so that the positive peak and the negative peak of the interface reflected wave are generated when the interface flaw exists at the interface. ### Claim 2 (depends on 1) The ultrasonic flaw detector according to claim 1, wherein an absolute value of the second threshold is larger than the first threshold. ### Claim 3 An ultrasonic flaw detecting method for a composite material, the composite material including a first material made of CFRP, a second material made of GFRP, and an interface disposed between the first material and the second material, each of the first material, the second material, and the interface having different physical properties from one another, the composite material formed by laminating the first material and the second material, the ultrasonic flaw detecting method comprising: irradiating the composite material from a first material side of the composite material with an ultrasonic wave so that a reflected wave of the ultrasonic wave includes an interface reflected wave, the interface reflected wave having a positive peak and a negative peak when an interface flaw exists at the interface; receiving an RF signal of the reflected wave; determining whether or not a material flaw exists by determining whether or not a value of the RF signal exceeds a positive first threshold in a first section of the RF signal, a material reflected wave being generated in the first section when a flaw exists in the composite material; and determining whether or not the interface flaw exists by determining whether or not the value of the RF signal falls below a negative second threshold in a second section of the RF signal, the interface reflected wave being generated in the second section when the interface flaw exists, the negative second threshold being a negative value less than 0. ### Claim 4 (depends on 3) The ultrasonic flaw detecting method according to claim 3, wherein: the composite material further includes a third material made of CFRP, and the composite material is a railcar plate spring having a three-layer structure in which the second material is sandwiched between the first material and the third material.