摘要
超塑性材料具有伸长率非常高,可以成形复杂构件等优点,已得到广泛应用。研究超塑性材料薄壁圆筒受内压的应力和应变率,导出壁厚变化和理论断裂时间计算公式,讨论不同材料壁厚和理论断裂时间的变化规律。计算结果表明:(1)圆筒越薄,理论断裂时间越小,越容易断裂。(2)应变速率敏感性指数m值与成形时间关系很大,m值增大使尺寸不同的材料的成形时间之间的差别趋于减小。(3)压力越大,理论断裂时间越小。当压力增大时,不同m值的理论断裂时间之间的差别趋于减小。(4)成形开始时,壁厚变化速度较慢;当成形时间接近理论断裂时间时,壁厚变化速度急剧增大。
Superplastic materials have advantages like high elongation, forming complex structures easily and so on, thus they have been widely used. Stresses and strain rates of superplastic thin walled cylinder under internal pressure were studied. Wall thickness variation and theory fracture times were derived. Yariation of different materials on wall thickness and theory fracture times was discussed. The results show that, （1） A thinner walled cylinder has a smaller theory fracture time, namely, the cylinder breaks more easily. （2） Strain-rate sensitivity index m has a lot to do with forming time. The m value increase enables forming time difference between different sizes of materials to tend to reduce. （3） The greater the pressure, the smaller the theoretical fracture time. The pressure increase enables theo~.＇y ti＇acture times ditt＇erence between different m values to tend to reduce. （4） Wall thickness variation is slow at the beginning of torming. When forming time close to theory fi＇acture time, wall thickness variation rate increases rapidly.
出处
《机械强度》
CAS
CSCD
北大核心
2013年第3期372-375,共4页
Journal of Mechanical Strength
基金
淮海工学院2011年自然科学类校内课题资助(Z2011132)
关键词
超塑性
应变速率敏感性指数
薄壁圆筒
理论断裂时间
厚度比
Snperplasticity
Strain-rate sensitivity index
Thin walled cylinder
Theory fracture time
Thickness ratio
