An Ultrasonic Measuring Method for Surface Stress of Composite Materials
An ultrasonic measurement and surface stress technology, which is applied in force/torque/work measuring instruments, measuring devices, instruments, etc., can solve the problems of high cost, low spatial resolution of measurement, and large size of the measuring device, so as to achieve simple and compact devices and improve the Measure spatial resolution, the effect of reducing the number of uses
Active Publication Date: 2020-04-07
DALIAN UNIV OF TECH
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[0004] In 2016, Liu Feifei and others disclosed "A Method for Obtaining Ultrasonic-Acoustic Emission Detection Signals of Composite Materials" in the invention patent CN201410275857.4. The sound beam directly receives the acoustic emission signal from the composite material part under test. However, this method is mainly used in the detection of composite material defects; in 2017, Zhang Yumin et al. disclosed in the invention patent CN201710154020. Anisotropic material plane stress device", this method is based on the anisotropic three-way method, a regular octagonal ultrasonic oblique incidence wedge is designed, and six ultrasonic transducers are used to form three "one send and one receive" structural forms, but , the measurement device is bulky and expensive, and the measurement spatial resolution is low
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[0022] The specific implementation of the present invention will be described in detail in conjunction with the accompanying drawings and technical solutions.
[0023] At room temperature of 25°C, the propagation velocity of ultrasonic longitudinal waves in the matrix is 2586.43m / s. In the T700 carbon fiber composite material, the maximum velocity along the fiber direction is 8971.02m / s, and the minimum velocity perpendicular to the fiber direction is 3638.4m / s. s, so according to formula (1), we know that the first critical refraction angle φ θ The maximum is 45.31°, and the minimum is 16.76°.
[0024] The key parameters of the variable-angle ultrasonic measurement device are: the width of the sliding component 8 is 20 mm, the radius of the base component 4 is 14 mm, the fixed distance between the transmitting end A and the receiving end B of the device is 8 mm, and the incident axis a and the receiving axis c can be realized by adjusting the sliding component 8 The maximu...
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An ultrasonic measuring method for the surface stress of a composite material, related to the technical field of ultrasonic testing. For the present method, first, a variable-angle ultrasonic measuring device is designed and assembled and then integrated with an ultrasonic transducer. Secondly, the ultrasonic measuring device is connected to a distal end of a robot (C) via a flexible coupling (D), an ultrasonic pulse transceiver system is installed, and the ultrasonic pulse transceiver is connected with the ultrasonic transducer. Finally, an acoustic elastic constant is calibrated for the composite material, thus completing a surface stress measurement. The present method, by designing and assembling a variable-angle of incidence ultrasonic measuring device, and by means of variable adjustments of the angle of incidence for ultrasound, adapts to the anisotropy of the ultrasonic propagation speed of the composite material. The device is simple and compact and increases the measuring spatial resolution. The present method satisfies composite material surface stress measuring requirements for manufacturing site environments, and implements the automated ultrasonic scanning and measuring of the surface stress with the aid of the robot (C).
Description
technical field [0001] The invention belongs to the technical field of ultrasonic detection, in particular to an ultrasonic measurement method for surface stress of composite materials. Background technique [0002] Composite materials have the advantages of small specific gravity, high specific strength and specific modulus, and are widely used in important industrial fields such as aerospace. However, composite materials are easily affected by temperature, chemical shrinkage and assembly during the manufacturing and application process, and residual stress is generated on the surface of composite materials, which seriously restricts the safe service life of parts. Nondestructive measurement of residual stress is very important for evaluating the performance of composite materials. is of great significance. Non-destructive measurement methods for residual stress include X-ray diffraction, Raman spectroscopy, and ultrasonic method. Ultrasonic method has the advantages of si...
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IPC IPC(8): G01L5/00
CPCG01L5/0047
Inventor 刘海波刘天然王永青李亚鹏刘彦坤贾振元
Owner DALIAN UNIV OF TECH