选区激光熔化成形Ti6Al4V的性能可靠性分析

Performance reliability analysis of Ti6Al4V manufactured by selective laser melting

  • 摘要:
    目的 该文以选区激光熔化(Selection laser melting, SLM)成形的Ti6Al4V为例,分析主要加工参数对材料性能的影响情况。
    方法 采用Elman神经网络(Elman neural network,ENN),在少量试验数据的基础上获取三水平三因素全因子设计数据,以节省时间和成本。采用多元回归分析(Multiple regression analysis,MRA)对三水平三因素全因子设计的数据进行拟合,得到各性能关于工艺参数的多项式。利用拟合的多项式获得各性能对应的极限状态方程,并使用二阶矩法(Second moment method,SM)计算选区激光熔化成形Ti6Al4V试样的可靠度,与蒙特卡洛法(Monte Carlo method,MCM)得到的结果进行对比。通过对可靠性灵敏度的计算,分析各工艺参数对各性能可靠性的影响程度。
    结果 ENN对Ti6Al4V试样的抗剪强度、硬度和密度3种性能均有较好的预测能力。MRA获得各性能的拟合方程均具有良好的预测精度。采用蒙特卡洛法和二阶矩法计算可靠性指标、失效概率和可靠度,2种方法的计算结果都很接近。在给定的工艺参数和性能值条件下,获得合格产品的可靠度为0.999675
    结论 激光功率与可靠性呈正相关,扫描速度和扫描间距与可靠性呈负相关。各变量对可靠性的影响由大到小依次为扫描速度、激光功率和扫描间距。

     

    Abstract: Objective This paper takes Ti6Al4V manufactured by selective laser melting as an example to analyze the influence of the main parameters on the material performances. Methods Elman neural network (ENN) is used to obtain three-level and three-factor all-factor design data based on a small amount of experimental data so as to save time and cost. Multiple regression analysis (MRA) is used to fit the data of three-level and three-factor full-factor design so as to obtain the polynomiasl of each performance with respect to parameters. The limit state equations corresponding to each performance are obtained by the polynomials. Second moment method (SM) is used to calculate the reliability of Ti6Al4V manufactured by SLM. The results are compared with those obtained by Monte Carlo method (MCM). Through the calculation of reliability sensitivity, the influence degree of each parameter on the reliability of each performance is analyzed. Results ENN has a good predictive ability for the three properties of Ti6Al4V specimen, such as shear strength, hardness and density. The fitting equations of each performance obtained by MRA all have good prediction accuracy. The reliability index, failure probability and reliability are calculated by the Monte Carlo method and the second moment method. The calculation results of the two methods are very close. Under the given parameters and performance values, the reliability of obtaining qualified products is 0.999675. Conclusion Laser power is positively correlated with reliability, while scanning speed and scanning spacing are negatively correlated with reliability. The order of influence of each variable on reliability from large to small is scanning speed, laser power and scanning spacing.

     

/

返回文章
返回