高温SHPB冲击实验技术及其应用

A High Temperature SHPB Impact Experimental Technique and Its Application

为研究高温下材料的动态力学性能,研制了一套适用于分离式霍普金森压杆(SplitHopkinson Pressure Bar,SHPB)高温冲击实验的温控系统。利用该温控系统和Ф100mm常规SHPB装置,对混凝土在高温下的动态力学性能进行了实验研究,实验温度分别为20、200、400、600、800和1 000℃。结果表明:由管式实时加热装置和箱式预加热炉组成的温控系统操作方便,实验效率高,试件组装方法简便可行;热传导导致的试件温度分布不均匀和压杆局部温升对实验结果产生的影响可以忽略,实验技术可靠;高温下混凝土动态力学性能的温度效应十分明显,相同冲击速率下,随温度升高,平均应变率逐渐增大,动态应力-应变曲线逐渐表现出塑性特性,动态抗压强度随温度升高先增大后减小,动态峰值应变随温度升高不断增大。

A set of temperature-controlling system adapted to high temperature split Hopkinson pres- sure bar （SHPB） experiments is developed and presented. Using this high temperature SHPB system comprised of a temperature-controlling system and a general Φ100 mm SHPB apparatus,the dynamic mechanical properties of concrete are investigated at 20,200,400,600,800 and 1 000 ℃, respectively. The experimental results show that the temperature-controlling system composed of a box preheating furnace and a tube real-time heating device is convenient to operate and can improve efficiency greatly, and the sample assembly method is simple and feasible;the temperature variance of sample and the lo- cal temperature rising of pressure bar due to heat conduction can be ignored, and the experimental technique is reliable. Temperature effects on dynamic mechanical properties of concrete at high temper- ature are obvious. With temperature increasing, the average strain rate and dynamic peak strain in- crease gradually, and the dynamic stress-strain curves exhibit plastic properties;moreover, the dynamic compressive strength rises at first and then falls.