HTPB推进剂/衬层单轴拉伸及损伤特性试验研究

Experimental study of uniaxial tensile and damage characteristics of HTPB propellant/liner

为研究单轴拉伸过程中固体发动机矩形粘接试件在不同尺寸开口裂纹和加载速率下的力学行为,以及粘接界面在脱粘情况下推进剂/衬层/绝热层细观损伤特性,对端羟基聚丁二烯(HTPB)推进剂/衬层矩形粘接试件进行了开口裂纹尺寸15、20、25、35 mm,加载速率3.85、77.14、385.71 mm/min的单轴拉伸试验,分析了矩形粘接试件单轴拉伸的力学性能变化规律,并推导计算了最大抗拉强度以及界面能的变化情况,利用微CT分析了开口裂纹20 mm、77.14 mm/min条件下试件断裂端面细观形貌和内部孔隙特征。结果表明,单轴拉伸情况下矩形试件的力学性能和加载速率有关,开口裂纹尺寸20 mm,加载速率385.71 mm/min加载条件下最大抗拉强度为1.46 MPa,界面粘接能达到17.66 J。推进剂侧断面主要表现为明显的大孔洞,衬层/绝热层一侧断面有明显的空穴、孔隙和颗粒存在。在拉伸过程中推进剂损伤主要表现为颗粒基体脱湿和孔隙汇集,衬层/绝热层,损伤主要表现为大面积的基体撕裂。

In order to study the mechanical behavior of solid motor rectangular bonded specimens with different sizes of open cracks and loading rates during uniaxial tensile process,as well as the microscopic damage characteristics of the propellant/liner/insulation layer in the case of debonding of bonding interface,the uniaxial tensile tests of HTPB(hydroxyl⁃terminated polybuta⁃diene)propellant/liner rectangular bonded specimens with opening crack sizes of 15 mm,20 mm,25 mm and 35 mm and loading rates of 3.85 mm/min,77.14 mm/min and 385.71 mm/min were carried out.The mechanical properties of rectangular bonded speci⁃mens under uniaxial tension were analyzed,and the changes of maximum tensile strength and interface energy under uniaxial tension test were deduced and calculated.And micro⁃CT was used to extract and analyze the micro⁃morphology and internal pore character⁃istics of the fracture end surface of the specimen under the condition of 20 mm opening crack and 77.14 mm/min loading rate.The results show that the mechanical properties of the rectangular specimen under uniaxial tension are related to the loading rate,and the maximum tensile strength is 1.46 MPa under the conditions of 20 mm opening crack size and 385.71 mm/min loading rate,and the interfacial bonding energy reaches 17.66 J.The cross section of propellant mainly exhibits obvious large holes,pores and particles.The propellant damage is mainly manifested as particle matrix dehumidification and pore aggregation.During the tensile process,the damage of liner/insulation layer mesoscopic scanning is mainly manifested as large matrix tearing.