3D打印类岩石材料强度特性与动态损伤本构模型

为研究基于3D打印的层状类岩石材料动态损伤力学行为,对5组不同倾角的岩样,采用分离式霍普金森杆对其进行动态压缩试验。依据所得的应力-应变数据,以朱-王-唐本构模型为基础,建立一种线性弹簧体、Weibull分布损伤体和Maxwell体并联的黏弹性本构模型,并结合试样的残余强度特性引入损伤修正系数。最后,将其推广应用于黑色页岩的变形规律研究,以检验该本构模型的适用性。结果表明：动态冲击下岩样峰值应力随着倾角的增加呈现先减小后增大的“V”形变化趋势,与天然层状岩石的变化规律相符合;所构建的损伤本构模型,能准确地表征3D打印的层状类岩石材料的应力-应变曲线形状及其力学特征;考虑损伤修正后,其还可较好地反映试样峰后阶段应力应变变化特性与残余强度。研究结果对揭示层状岩石动载下变形规律具有一定参考价值。

Strength property and dynamic damage constitutive model of 3D printed rock-like material

To investigate the dynamic damage mechanical behaviors of bedded rock-like material based on 3D printing, dynamic compression tests on five groups of printed samples with different dip angles were carried out using a split-Hopkinson pressure bar. Then, according to the obtained stress-strain data and Zhu-Wang-Tang constitutive model, a viscoelastic constitutive model was constructed by connecting the linear spring body, the Weibull distribution damage body, and the Maxwell body in parallel, and the damage correction coefficient was introduced in combination with the residual strength properties of the samples. Finally, the model was extended to explore the deformation patterns of black shale to verify its applicability. Results showed that under impact loading, the peak stress of samples displayed a "V" shaped trend with the increase in dip angle, which was consistent with the variation pattern of natural layered rock. The damage constitutive model accurately characterized the shape of the stress-strain curve and the mechanical behaviors of the 3D printed bedded rock-like material. After considering the damage correction, it also better depicted the stress-strain change characteristics and residual strength of the samples at the post-peak stage. This study is useful for understanding the deformation pattern of bedded rock subjected to dynamic loading.