基于计算热力学的CaO-Al_2O_3-SiO_2熔渣SAW致氧机理分析

基于熔渣的分子离子共存理论,结合高温相图,对CaO-Al2O3-SiO2三元渣系进行了热力学计算,定量分析了不同碱度下熔渣结构单元的变化特征,以及碱度对高温熔渣结构单元活度的影响。通过对CaO-Al2O3-SiO2三元渣系不同碱度下各组元变化规律的分析,定量地解释了随熔渣碱度的增大,熔渣的分子特性相对减弱,而离子特性逐渐明显的原因。对比熔渣不同碱度下,激冷熔滴热化学增氧和电化学增氧的变化趋势,解释了直流埋弧焊正反接时,激冷熔滴含氧量不同的原因,为冶金化学增氧分析提供了一种新的思路。

基于虚拟仪器的多信息融合电阻点焊质量检测系统研究

采用虚拟仪器技术和多信息融合技术建立了对铝合金点焊质量的检测系统。系统应用分形理论对焊接过程中采集的数据信息进行了处理,使用虚拟仪器工具编程提取了更能反映所采集信号统计特征和变化特征的盒维数。在对焊点质量与焊接过程中信息的盒维数统计物理关系的分析基础上建立了基于模糊控制理论的焊点质量判定系统。仿真实验结果表明,本系统能够准确地判定电阻点焊的焊点质量。与传统的电阻点焊质量检测系统相比,具有更加准确、快速和成本低廉的优点。

氧含量对CaO-Al_2O_3-SiO_2渣直流SAW金属熔滴组织的影响

采用实验室自制的不同碱度焊剂,使用水冷铜板提取激冷熔滴,同时采用先进的分析手段对熔滴的氧含量进行分析,并根据共存理论对熔滴反应区的增氧机理进行了探讨,分别从电化学和热化学方面分析了氧含量对熔滴的尺寸、显微组织及内部夹杂物变化规律的影响,给出了比较合理的解释。

Eigenvalue extraction of current signal during spot welding based on space-phase reconstruction

Nonlinear methods are used to analyze current signal of spot welding and the minimum embedding dimension, correlation dimension, the optimal time delay and the largest Lyapunav exponent of current signal time series are calculated in this paper. The chaotic character of current signal time series is discovered. Then a chaotic neural network is built and used to predict the future current signal. Means of residual error out of the network are used as eigenvalue of current signal during spot welding. It is shown that spatter can greatly affect the means of residual error of spot welding after analysis, the mean values of output errors of signal contaminated by spatter noise are more than 0. 08, but the mean values of output errors of the signal with no spatter noise are less than 0. 04, so mean of residual errors can be employed as the character of spatter.