	US 12,360,013 B2
	Defect detection
Matt Jones, Southampton (GB)
Assigned to HITACHI RAIL LIMITED, London (GB)
Appl. No. 18/009,264
Filed by HITACHI RAIL LIMITED, London (GB)
PCT Filed May 27, 2021, PCT No. PCT/EP2021/064182 § 371(c)(1), (2) Date Dec. 8, 2022, PCT Pub. No. WO2021/249782, PCT Pub. Date Dec. 16, 2021.
Claims priority of application No. 2008614 (GB), filed on Jun. 8, 2020.
Prior Publication US 2023/0258537 A1, Aug. 17, 2023
Int. Cl. G01M 7/00 (2006.01); G01M 17/10 (2006.01)

CPC G01M 17/10 (2013.01) [G01M 7/00 (2013.01)]

31 Claims

1. A method of detecting defects in a mechanical system, the method comprising the steps of:

a. providing a mechanical system;

b. subjecting the mechanical system to random vibration by a vibration device to cause the mechanical system to vibrate and output an output vibration;

c. detecting the output vibration using a vibration detection device;

d. using a processing system to carry out the substeps of:

i. selecting a plurality of frequencies within the output vibration wherein a plurality of groups of vibration measurements are selected, each group having a common time period, wherein successive groups partly overlap in time and are shifted in time by a time shift (dt₂);

ii. analysing the plurality of frequencies to extract phase information for the plurality of frequencies;

iii. generating a continuous phase waveform representing modulation in phase over time for one or more frequencies of the plurality of frequencies; and

iv. detecting peaks in the continuous phase waveform at multiples of an input vibration frequency to produce output data representing defects in the mechanical system.