用时频分析法研究铝合金电阻点焊过程中的声音信号

研究了铝合金点焊过程中声音信号的时频域能量分布，并应用它来识别点焊的熔核状态。点焊过程中的声音信号包含着熔核形成信息，是点焊质量监控的重要参数。为了能够确定熔核的变化状态，作者尝试采用非平稳过程的时频分析方法对声音信号进行研究，试验与计算结果表明，Choi-williams时频分布是一种较好的铝合金点焊声音分析方法，可以区分不同熔核状态，其计算结果可作为铝合金点焊过程的监控参数和质量检验的依据，具有一定的实用价值，同时它对其它焊接方法中的信号分析与处理也有较高的参考价值。

Application of time-frequency analysis to air-borne acoustic signals of aluminum alloys spot welding

This paper investigates energy distribution of air-borne acoustic signals in time-frequency domain during aluminum alloys spot welding in order to identify weld nugget states. Experiment results indicate that air-borne acoustic signals contain information about weld nugget states and can be viewed as a kind of parameters that indicate the welding quality. Methods of time-frequency analysis are put forward to analyze the non-stationary signals. The results of experiment and calculation show that Choi-Williams distribution, a kind of time-frequency analysis, has been proved to be a better approach to discriminate weld nugget states by analyzing the signals. As a result, it can be employed to recognize signals in the industrial application and can provide a new way for various welding processes.