发泡陶瓷的压溃特性实验研究

Experimental Study on Crushing Characteristics of Foam Ceramics

通过轴向准静态无约束压溃实验,揭示了发泡陶瓷受压溃变的破坏形态和压应力-应变特点。实验观测发现,发泡陶瓷在屈服后的朔性段出现朔性强化段。对此段出现的原因,认为是由于溃变粉化碎片积累在压溃界面的孔隙中造成实际接触面积增加所导致,并通过加卸载实验证实。为进一步证实在压溃界面上的这种效应,进行发泡陶瓷加盖实验,发现加盖后屈服应力会急剧增加。此外,提出了符合发泡陶瓷实验观测结果的六段压溃本构特征。

Failure modes and compressive stress-strain characteristics of foamed ceramics under compression are revealed through uniaxial quasi-static unconstrained crushing experiments.The strain hardening after yielding in the first plastic section of stress-strain diagrams is observed,which is abnormal for porous materials usually.The hypothesis to explain the hardening is that the actual contact areas between sample ending surfaces and surfaces of the loading heads increase due to the accumulation of pulverized debris filled into the pores at the contact interface,which is confirmed with the designed loading-unloading experiments.In order to further confirm the area effect at the contact interface,the capping experiment of foamed ceramics is carried out,and finds that the yield stress can increase sharply.In addition,a six-stage crushing constitutive characteristic,which is consistent with the experimental observations,is proposed.