EI、Scopus 收录
中文核心期刊

HTPB复合底排药压缩屈服应力模型研究

RESEARCH ON MODELING OF COMPRESSIVE YIELD BEHAVIOR FOR HTPB COMPOSITE BASE BLEED GRAIN

  • 摘要: 目前广泛应用于底排增程技术的 HTPB 复合底排药 (composite base bleed grain,CBBG) 是一种颗粒填充含能材料,战场环境中将承受冲击、温度等载荷作用. 为研究 HTPB CBBG 冲击压缩力学性能,进行了不同温度 (233\sim323 K) 和应变率 (1100\sim7900 s^-1) 下的分离式霍普金森压杆实验. 实验结果表明,各工况下,应力应变曲线均呈现屈服-\!-应变硬化特征,HTPB CBBG 保持高韧性. 提高应变率和降低温度均导致相同应变下的应力幅值上升,但温度较应变率对HTPB CBBG 冲击压缩力学性能的影响更为显著. 基于所研究温度范围高于 HTPB CBBG 玻璃化转变温度,通过将水平、垂直移位因子与温度的关系表示为 WLF 方程的形式,将时温等效原理引入协同模型,并计及内应力的应变率增强效应,提出了一种新的屈服应力模型.选取参考温度,利用水平、垂直移位因子-\!-温度曲线和屈服应力主曲线拟合模型参数.模型预测值与实验数据对比结果表明:该模型可准确表征 233\sim323 K 时 HTPB CBBG 屈服应力的双线性应变率相关性,明确了较低和较高应变率时,应变率效应分别主要由内应力和驱动力贡献.

     

    Abstract: HTPB composite base bleed grain (CBBG), which has been widely applied to the base bleed extended-range technology, is a typical particle-filled energetic material and bears both impact and temperature loads in battlefield environments. In order to investigate impact compressive mechanical properties of HTBP CBBG, split Hopkinson pressure bar experiments were conducted at various temperatures and strain rates, ranging from 233 to 323 K and from 1100 to 7900 s^-1. True stress-true strain curves shows that HTPB CBBG yields and then deforms plastically with strain hardening effect and maintains high toughness under each experimental condition. The stress value at a certain strain increases with the increase of strain rate and the decrease of temperature, but temperature has a more significant influence on impact compressive mechanical behaviors of HTPB CBBG than strain rate. On the one hand, the time-temperature superposition principle was introduced into the cooperative model by taking the correlations between horizontal/vertical shift factor and temperature as WLF function-type equations based on the fact that the temperature range discussed here was higher than the glassy transition temperature of HTPB CBBG. One the other hand, the enhancement effect of strain rate of internal stress was also taken into consideration, and then a new stress model was proposed. The smooth horizontal shift factor-temperature curve, vertical shift factor-temperature curve and master curve of yield stress were built at a reference temperature according to experimental results to obtain the parameters in the proposed model. The comparison between the model prediction and experimental data indicates that the developed model can precisely describe the bilinear dependence of yield stress on strain rate at temperatures of 233\sim 323 K. The proposed model points out that the strain rate effect is derived from internal stress at low strain rates while it is derived from drive stress at high strain rates.

     

/

返回文章
返回