基于对数正态分布的VFD加速寿命试验研究

Investigation on accelerated life test of VFD based on lognormal distribution

为了能在较短的时间内预测真空荧光显示屏(VFD)寿命,提出了一种加速寿命预测的试验方案.通过加大VFD灯丝应力温度,开展了两组恒定应力温度加速寿命试验和一组步进应力温度加速寿命试验.应用对数正态分布函数描述了VFD寿命分布,利用最小二乘法(LSM)估计出均值和标准差,完成了恒定及步进应力温度试验数据的统计和分析,并自行开发了寿命预测软件.数值结果表明,该试验方案是正确可行的,VFD的寿命服从对数正态分布,其加速模型符合阿伦尼斯方程,加速参数的精确计算使得快速估算VFD的寿命成为可能.

To forecast the life of vacuum fluorescent display （VFD） in shorter time, an experimental scheme of the accelerated predicted-life test was presented. When the VFD filament stress temperature was increased, two groups of constant stress temperature accelerated life tests and a group of step stress temperature accelerated life test were conducted. After the life distribution of VFD was described by applying the lognormal distribution function, the equalizing value and the standard deviation were estimated using the least square method （LSM）, and the statistics and analysis on constant stress and step stress temperature test data were achieved. The predicted-life software was self-designed. The numerical results show that the scheme is correct and feasible, and that the VFD life is characterized by lognormal distribution, the accelerated model meets Arrhenius equation. Accurate calculation of the acceleration parameters enables rapid estimation of VFD life.