【摘要】 早期发现车轮的初始疲劳裂纹是避免铁路车辆行车事故的最有效的方法。采用弹性力学的理论,分析了疲劳裂纹产生时弹性波的主要传播形式及声发射现象,分析了疲劳裂纹信号与噪声信号在波形、频率和幅度上的明显区别,提出了测量点位的确定原则和用宽带声发射传感器接收疲劳裂纹信号采取的措施及硬软件去噪的方法。建立了应变能与疲劳裂纹信号之间的数学模型。通过高保真宽带传感器实时真实地获取被测材料结构中产生的宽带声发射信号,并分析研究源产生的超声波模式,找出对应模式波的内在持征,即可进行缺陷的参数识别和定位。为车轮早期疲劳裂纹的识别提供了一种新方法。更多还原

【Abstract】 It’s an effective method to avoid the rupture of the train wheels that finding the initial tired flaws at early stage. The main transmitting styles of elastic waves and acoustic emissions when tired flaws bring are analyzed in this paper using the theory of elastic mechanics. Obvious differentiation of the tired flaw signals from the noises signals in waveforms, frequency and amplitude are analyzed when the broadband acoustic emission sensors are adopted to collect acoustic emission signals. The certainty principles to measure the point position, the measurements adopted in receiving tired flaw signals using broadband acoustic emission sensors and the methods to remove noises with hardware and software are brought forward. Mathematic model between strain energy and tired flaw signals is established. Broadband acoustic emission signals produced in the measured materials are acquired real time and really by the high fidelity broadband acoustic emission sensors. Ultrasonic modes brought at the source are analyzed and inherent characters of corresponding mode waves are found out, by which parametric recognition and orientation of the disfigurement could be processed. A new method to identify the initial tired flaws is provided.更多还原