基于DIC古建筑青砖受冻融循环作用的损伤演化

Damage Evolution of Ancient Building Blue Bricks under Freeze‑Thaw Cycle Based on DIC

以内蒙古隆盛庄古建筑青砖砌体为研究对象,通过数字图像相关(DIC)技术,研究古建筑青砖在冻融循环作用下的损伤破坏规律,采用双因子——损伤程度因子和损伤局部化因子来表征古建筑青砖的单轴压缩损伤过程,并根据双因子损伤演化曲线建立了不同冻融循环次数下的损伤演化模型.结果表明:古建筑青砖在单轴压缩下的破坏过程可分为初始损伤闭合阶段、线弹性损伤阶段、弹塑性损伤阶段和塑性损伤阶段4个阶段;随着冻融循环次数的增加,青砖表面应变集中程度增大,使其承载能力降低;冻融循环会缩短双因子曲线的线弹性阶段,同时利用双因子建立的损伤演化模型能有效反映冻融循环作用下古建筑青砖材料的损伤演化过程.

Taking the ancient building wall of Longshengzhuang in Inner Mongolia as the research object,the damage and failure law of ancient building blue bricks under freeze-thaw cycles were investigated by digital image correlation(DIC)technology.Two-factor—damage degree factor and damage localization factor were used to characterize the uniaxial compression damage process of ancient building blue bricks.Based on the two-factor damage evolution curve,a damage evolution model was established under different freeze-thaw cycles.The results show that the failure process of ancient building blue bricks under uniaxial compression can be divided into four stages—initial damage closure stage,linear elastic damage stage,elastic-plastic damage stage and plastic damage stage.With the increase of freeze-thaw cycles,the strain concentration on the surface of blue brick increases,resulting in a decrease in bearing capacity.Freeze-thaw cycles will shorten the linear elastic stage in the two-factor curve.At the same time,the damage evolution model established by the two-factor can effectively reflect the damage evolution process of the ancient building blue brick material under the action of freeze-thaw cycles.