Acoustic Signal Processing Method in Friction Welding Process
A technology of welding process and processing method, which is applied in the field of acoustic signal processing, can solve the problems of poor practicability and achieve the effect of strong practicability
Inactive Publication Date: 2017-10-10
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology
[0003] In order to overcome the shortcomings of poor practicability of the acoustic signal processing method in the existing friction welding process, the present invention provides an acoustic signal processing method in the friction welding process
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[0014] refer to figure 1 . The specific steps of the acoustic signal processing method in the friction welding welding process of the present invention are as follows:
[0015] 1. Select the MicW i436 handheld microphone as the audible signal acquisition tool.
[0016] 2. Conduct continuous drive friction welding test on 2024-T6 aluminum alloy bar (sample specification: diameter 25mm, length 100mm, roughness of end surface to be welded 0.8), friction welding process parameters are set as: speed 1500RPM, friction pressure 80MPa , the upsetting pressure is 120MPa, the frictional shortening is 5mm, and the upsetting mechanism is carried out simultaneously with brake upsetting. Acoustic signals emitted during welding are collected using a microphone.
[0017] 3. Short-time Fourier transform is performed on the collected friction welding sound signal to obtain the time-frequency joint distribution map of the sound signal. The transformation parameters are: FFT length, 2560; win...
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The invention discloses a processing method for sound signals in the friction welding process. The processing method is used for solving the technical problem that an existing processing method for sound signals in the friction welding process is poor in practicality. According to the technical scheme, a capacitive type microphone is used for collecting the sound signals sent in the whole friction welding process; short-time Fourier transform is carried out on the collected sound signals, and a time-frequency combination distribution diagram of the sound signals is obtained; the maximum value point of the FFT calculation result of each frame in the time-frequency combination distribution diagram is screened, and the maximum value scatter diagram of the FFT calculation result of each frame is obtained; the points with the frequency value lower than 5,000 Hz in the maximum value scatter diagrams of the FFT calculation results of all the frames are filtered out; and according to the aggregation morphology of data points in the scatter diagrams, all the points are divided into three classes, and the three classes correspond to a quasi-steady stage, a steady stage and a brake stage in the friction welding process respectively. The sound signals in the friction welding process are simply processed, the friction welding process can be effectively distinguished, and the high practicality is achieved.
Description
technical field [0001] The invention relates to an acoustic signal processing method, in particular to an acoustic signal processing method in the friction welding process. Background technique [0002] An important prerequisite for real-time detection of friction welding is to study it in stages, which will help to further understand the forming mechanism of the joint and lay a theoretical foundation for the precise control of joint quality. The traditional method is to divide the welding process into four stages: initial, quasi-stable, stable, and brake upsetting according to the change of friction torque during the welding process. The most important technical problem involved is the measurement of friction torque. The measurement of friction torque includes two methods: direct measurement and indirect measurement. The direct method directly obtains torque data by attaching strain gauges to the workpiece or the spindle. Although the result is accurate, it is not suitable ...
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IPC IPC(8): B23K20/26B23K20/12G10L25/18
CPCB23K20/12B23K20/26G10L25/18
Inventor 傅莉白雪垠
Owner NORTHWESTERN POLYTECHNICAL UNIV