Approximate Calculation Method for Noncentral t-Distribution Quantile

In the process of structural design and performance evaluation, inference reliable life structure representative value material strength is a necessary work. The determination presumption quantile normal distribution, confidence level distribution involves noncentral t-distribution function. However, calculation very complicated often provided in form numerical table, which multiparameter interpolation calculation, so it not convenient to apply. existing approximate methods for quantiles have strict application conditions, relatively cumbersome. It still difficult meet actual needs terms fitting accuracy, range, convenience. this paper, new method proposed by introducing probability expressions related distributions, based on theoretical derivation fitting. comparative analysis results show that only but also has advantages higher accuracy wider more line with engineering.