艇载固体发动机药柱蠕变-疲劳损伤分析

关键词:大型固体发动机；立式贮存；交互试验；累积损伤；艇载

关键词:  大型固体发动机  立式贮存  交互试验  累积损伤  艇载

Key words:  Large-scale solid rocket motor  Vertical storage  Interaction test  Cumulative damage  Onboard

摘要:

为研究大型艇载固体发动机立式贮存状态下药柱经受长期自重和低频振动载荷作用下的累积损伤，开展HTPB推进剂定应力持续加载破坏试验、定应力幅值往复拉伸试验以及蠕变-疲劳交互试验，拟合了交互损伤本构方程；开展发动机固化降温、长期重力和低频振动联合作用下的有限元计算，得到了药柱应力应变分布规律；并基于Miner线性损伤理论对发动机药柱关键点和关键路径的累积损伤进行了计算。研究结果表明:蠕变作用与疲劳作用具有非对称性的交互作用；长期自重载荷作用下，药柱整体下沉，从头部至尾部下沉量依次减少，蠕应变占据药柱总应变的60%以上；周期性的低频振动后，应力应变呈现周期性变化；药柱内部累积损伤随时间呈线性关系，艇载贮存半年的累积损伤为0.0219。

Abstract:

In order to study the cumulative damage of large-scale solid motor grains on-board suffering gravity and low frequency vibration for a long time，the sustained loading destruction test, cyclic loading test with fixed stress and creep-fatigue interaction test of HTPB propellant were carried out, and the constitutive equation of interaction damage was obtained. The grain’s stress and strain distribution rules were obtained，by the motor’s finite element calculation under combined loadings of curing, long-time gravity and low frequency vibration. The cumulative damage of the key points and paths on the inner grain was calculated，based on the Miner’s linear damage theory. The results show that creep and fatigue possess asymmetric interaction. The whole grain sinks with long-time gravity, and the displacement decreases successively from the head to the tail, the creep strain accounts for more than 60% of the total strain. The stress and strain change periodically with periodical vibration. The cu?mulative damage of inner grain is linear with storage time, the damage for half a year on vertical storage is 0.0219.