Teyeb Ahmed, Salimi Mohamad, El Masri Evelyne, Balachandran Wamadeva, Gan Tat-Hean
Brunel Innovation Centre, Brunel University London, Uxbridge UB8 3PH, UK.
Department of Electronic and Electrical Engineering, Brunel University London, Uxbridge UB8 3PH, UK.
Materials (Basel). 2023 Jan 1;16(1):410. doi: 10.3390/ma16010410.
This paper explains the use of remote ultrasound vibration at the optimum position and frequencies to vibrate plates under welding, with the aim of initiating cavitation in the molten pool area. It has been shown in the literature that ultrasound cavitation changes microstructure morphology and refines the grain of the weld. In practice, the plates are excited through narrow-band high-power ultrasound transducers (HPUTs). Therefore, a theoretical investigation is carried out to identify the plate-mode shapes due to the ultrasound vibration aligned with the frequency bandwidth of HPUTs available in the marketplace. The effect of exciting the plate at different locations and frequencies is studied to find the optimum position and frequencies to achieve the maximum pressure at the area of the fusion zone. It was shown that applying the excitation from the side of the plate produces an order of 103 higher vibration displacement amplitude, compared with excitation from the corner. The forced vibration of cavitation and bursting time are studied to identify vibration amplitude and the time required to generate and implode cavities, hence specifying the vibration-assisted welding time. Thus, the proposed computational platform enables efficient multiparametric analysis of cavitation, initiated by remote ultrasound excitation, in the molten pool under welding.
本文阐述了在焊接过程中，利用最佳位置和频率的远程超声振动来振动板材，目的是在熔池区域引发空化现象。文献表明，超声空化会改变微观结构形态并细化焊缝晶粒。在实际操作中，板材通过窄带高功率超声换能器（HPUTs）进行激发。因此，开展了一项理论研究，以确定与市场上现有HPUTs频率带宽一致的超声振动所导致的板材模态形状。研究了在不同位置和频率下激发板材的效果，以找到在熔合区实现最大压力的最佳位置和频率。结果表明，与从角部激发相比，从板材侧面施加激发会产生高103倍的振动位移振幅。研究了空化的强迫振动和破裂时间，以确定振动幅度以及产生和内爆空化所需的时间，从而确定振动辅助焊接时间。因此，所提出的计算平台能够对焊接过程中熔池内由远程超声激发引发的空化进行高效多参数分析。
