摘要:
开展了圆柱形爆炸容器逐级加载和破坏实验,根据容器最终的断裂面和微观形貌观测,提出了爆
炸容器绝热剪切失效模式。建立了应变率-应变空间内的绝热剪切损伤演化模型,将绝热剪切不同演化阶段
的临界状态与宏观的力学条件联系起来,并将这些力学临界条件作为动态失效准则引入到宏观计算程序中,
模拟爆炸容器发生绝热剪切的的瞬态过程,模拟结果成功预测了爆炸容器最终的断裂形貌。数值模拟结果还
表明,爆炸载荷和率相关失效准则是控制绝热剪切失效模式的2个主要因素,细观初始缺陷往往导致绝热剪
切的激发,但对容器最终的失效模式的影响是次要的。当容器在爆炸载荷作用下发生绝热剪切破坏模式时,
裂纹(剪切带)扩展速度较快,此时若仍采用整体塑性应变失效准则考察容器的动力响应并作为失效判据,将
不能预见材料局部的弱化和破坏。
Abstract:
Destructiontestswereperformedonacylindricalexplosioncontainmentvessel(ECV)by
applyingtheexplosiveloadswiththeincreasingchargemassesofTNT.Anadiabaticshearfailure
modeforECVswaspresentedbasedonthefractureandthemicro-opticalobservationofthedestructedvessel.
AdamageevolutionmodelforECVssubjectedtoadiabaticshearwasconstructed,where
themechanicalconditionsincludingstrainrateandstrain werelinked withthedifferentevolution
statesoftheadiabaticshearbands(ASBs).AndthesemechanicalconditionswereemployedinthenumericalcodeasthefailurecriteriatosimulatethetransientprocessoftheASBevolution.
Thesimulatedfractureprofileshowsagoodagreementwiththeexperimentalresult.
Thesimulatedresultindicatesthattherate-
dependentcriticalstrain,aswellasexplosiveload,governstheadiabaticshearfailuremode.
ThoughtheinitialmaterialimperfectionignitestheASBs,ithasaminorinfluenceonthe
finalfractureprofile.FortheECVswiththeadiabaticshearfailuremode,thecrack (orASB)expandsfasterthanforthosewiththeplasticinstabilityfailuremode.
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