发泡陶瓷有约束轴向压溃特性及泊松比测量

为了揭示发泡陶瓷的力学特性，进一步验证塑性变形特征，对发泡陶瓷进行有约束轴向压溃实验。针对有约束实验中柱形压头固定和柱形压头与约束套筒共轴的问题，优化设计了一套简单实用的实验装置，包括简单夹具固定柱形压头，止推轴承钢保持架叠放垫片实现柱形压头和不锈钢套筒在实验过程中实时共轴。在有约束和无约束实验条件下，分别得出两组不同密度发泡陶瓷的屈服极限和弹性模量。根据平均屈服极限由经验公式间接计算出较小的泊松比，分别为0.100 9和0.073 45。对两组样品无约束组和有约束组屈服极限和弹性模量进行两组样品t检验，检验结果表明在统计学意义上发泡陶瓷的泊松比可能为0。

Confined uniaxial crushing characteristics and Poisson’s ratio of foamed ceramics

In order to reveal the mechanical characteristics of foamed ceramics and further verify the plastic deformation characteristics, the foamed ceramics were tested with constrained axial crushing. In view of the problems to hold the compression head properly and keep the axial alignment with a compression head, a cylindrical con-straint, a specimen and the experiment machine, a set of simple and practical experimental devices is designed and optimized, including a simple fixture to hold the compression head and a freely skidding platform to keep real-time alignment of the head and constraint. The yield limit and elastic modulus of foamed ceramics with different densities are obtained based on experimental results, and the Poisson ratio is calculated to be 0.1009 and 0.07345 with empirical formulas based on obtained yield limit of two different density groups – heavier and lighter, respectively. The two-sample t-test of the yield limit and elastic modulus reveals that there is no statistical difference between the unconstrained and constrained experimental yield limits and elastic moduli, and the Poisson ratio of the foamed ceramic is not statistically nonzero.