循环载荷下粘接接头真空性能的实验研究

Experimental study on vacuum performance of adhesively bonded joint under cyclic load

粘接接头在经历反复冷却、复温后能否保持良好的真空密封性,是决定无磁杜瓦耐用性的一个重要因素。该文实验研究了循环载荷对粘接接头气密性的影响。用MTS 810材料试验机对玻璃钢管状粘接试样施加循环载荷,并用动态真空法测量试样真空度的变化。结果一半试样的真空度随循环次数的增加而降低,而其余试样破坏前真空度变化不大。因此,无磁杜瓦在使用过程中反复冷却及复温所产生的循环应力载荷,是导致其真空性能下降的一个重要原因。

Whether the adhesively bonded joints keep good vacuum tightness after experiencing repeatedly cooling and heating is an impertant factor that determines the durability of nonmagnetic Dewar. In this study, effect of cyclic load on the vacuum tightness of the adhesively bonded joint was investigated experimentally. Cyclic load was exerted on the glass fiber reinforced plastic （GFRP） sample that was composed of adhesively bonded tubular joint by MTS 810 material test system. Vacuum of sample was measured using dynamic vacuumpumping method. Results show that vacuum of half of samples decreased with the increase of cycle index while that of the others hardly changes before samples fail. Therefore, the cyclic stress caused by repeatedly cooling and heating during the usage of non-magnetic Dewar is one of the important reasons that causes the decrease of vacuum performance.