基于推广疲劳-蠕变等效转换理论的高温条件载荷谱编制方法

针对现有载荷处理方法对高温条件下保载时间内损伤的忽略或考虑不足问题，对疲劳-蠕变转换理论进行了推广，给出普适的转换模型建立流程，以此修正雨流计数中的等值点压缩、小幅值剔除等数据压缩步骤，从而获得了能够量化全工况保载损伤的高温条件载荷谱编制方法。在航空发动机高压涡轮盘上的应用表明：本方法考虑了全工况等值及小幅值载荷贡献的疲劳-蠕变耦合损伤，其相当于纯疲劳循环（传统雨流法）的298.25%，比常规转换方法多236.91%；寿命预测误差为8.35%，较常规转换方法降低了95%，仅为传统雨流法的2.5%，证明了优化的高温条件载荷谱编制方法的应用价值。     

Preload relaxation analysis and reliable life prediction of space connection and separation device based on accelerated degradation tests

The safety and reliability of space connection and separation device has become a key issue due to the increasing service span of deep space exploration mission. The long-term preload relaxation (a key failure mode) of connection and separation devices is focused in this paper. A series of tests have been designed and implemented to investigate the preload relaxation regulation and a comprehensive method has been constructed to analyze and predict the reliable lifetime of the device. The two-stage preload relaxation law of the device is found and reasonably considered. Due to the different relaxation mechanism, the first-stage preload relaxation is assessed based on the working-condition test results, and the second-stage preload relaxation is characterized by accelerated test results. Finally, the service reliability and reliable life are evaluated. The experiment and assessment results demonstrate the reasonability and effectiveness of the proposed method which can achieve long-service reliability analysis for space connection and separation device within limited time.     

航天橡胶密封材料及制品贮存寿命评估技术进展

橡胶密封材料是航天器重要的组成部件，但受复杂的服役环境影响，有不断老化的趋势和失效风险。因此，橡胶密封材料的贮存寿命研究具有重要意义。本文结合橡胶密封材料在航天产品上的应用，介绍了其贮存寿命评估技术的研究现状及主要技术途径，分析了密封橡胶材料的加速贮存典型寿命预测方法，并依据航天探索的实际迫切需求对未来研究方向进行展望。     

A physically-based representative stress methodology for predicting stress rupture life of Ni-based DS superalloy

Smooth and three types of U-shape single-edge notched plate specimens adopted to experimentally investigate stress rupture behavior of Ni-based Directionally Solidified (DS) superalloy at 850 °C exhibit notch weakening effect and multi-source cracking initiation near the notch root. However, stress rupture behavior of smooth and V-shape notched round bars at 1040 °C revealed by Li et al indicates notch strengthening effect and creep micro-holes originating mostly from the central portion. A combined creep-viscoplastic constitutive model is employed to analyze the distribution of stress, strain and stress Triaxial Factor (TF) near the notch root. The different stress distribution and creep restraint between asymmetric notched plate specimens and symmetric notched round bars are the main reasons for the corresponding failure mechanism. Meanwhile, a good qualitative relationship exists between TF value and stress rupture life of notched specimen. Especially, the area with maximum TF value (TF_max) is highly consistent with creep damage initiation region. Hence, based on the distribution characteristics of the initial tensile loading, a representative stress method independent of time -changing creep load at the location of TF_max is conducted for life prediction. The predicted results of both smooth and notched plate specimens and round bars agrees well with the experimental results.     

航空装备全寿命周期费用多路径管控策略研究

航空装备作为高新技术复杂产品,其经济性设计越来越受到重视。在满足用户需求的前提下,如何控制并尽可能降低全寿命周期费用是航空装备研究的重点。通过对全寿命周期费用管控理论和方法的研究,总结以往航空装备研制中经济性工作的经验和教训,结合我国军工产品经费管理的特点,从思想观念、管理和技术等方面入手,提出一套在设计阶段适合我国航空装备全寿命周期费用多路径管控的策略,并在某型飞机研制中试点应用。结果表明:某型飞机研制费用管控效果较好,验证了该策略的合理性和有效性。