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摘要: 采用巴西实验作为间接拉伸加载手段,研究了某PBX(polymer-bondedexplosive)炸药试样拉伸作 用下的断裂损伤特性。发展了PBX炸药的光学制备技术,获得了试样在光学显微镜下的细观表面形貌和断 裂损伤形貌,结合高速摄影和数字相关分析技术获得了试样的形变和破坏过程。实验结果表明该PBX炸药 的静态拉伸强度低于3MPa,破坏应变也非常小。根据观测结果,运用晶体穿晶断裂和临界脱粘理论对PBX 炸药的拉伸断裂模式进行了分析,认为脱粘裂纹在加载早期即可成核;当晶体开始发生断裂后试样发生宏观 破坏。颗粒尺寸较大的晶体容易发生穿晶断裂,颗粒尺寸很小的晶体则容易发生界面脱粘。Abstract: Thequasi-staticBraziliantestwasperformedontheMTSmachinetoinvestigatethetensile fracturemodesofthePBXspecimen.AnopticalpreparationtechniqueforthePBXspecimenwasdevelopedtoobtainmorevividmicrostructurefeaturesunderopticalmicroscopes. Andthedeformation anddamageevolutionsofthespecimenweregainedbyadoptingahigh-speedcameraandthedigital imagecorrelationmethod.ResultsshowthatthetensilestrengthofthePBXislessthan3MPaand itsfailurestrainisconsiderablysmall.Basedontheobservedresults,thetensilefracturemodesofthe PBXexplosivespecimenwereanalyzedbyapplyingtheGriffithfracturecriterionandtheinterface debondingtheory.Analysisrevealsthattheinterfacedebondingcrackwillinitiateintheearlystageof loadandthetransgranularfractureleadstothefailureofthespecimen.Largercrystalsareproneto crackthroughthemselves,andsmalleronescankeepthemselvesfromtrangranularcleavagefracture butonlydebondfromthebinders.
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Key words:
- olidmechanics /
- PBX /
- Braziliantest /
- micro-damageoffracture /
- digitalcorrelationtechnique
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