不同分级循环加卸载模式下六边形蜂窝能量演化规律

Energy evolution of hexagonal honeycomb under different graded cyclic loading and unloading modes

为了阐明循环加卸载路径对六边形蜂窝能量演化的影响规律,设计了3种不同分级循环加卸载试验,揭示了不同分级循环加卸载模式下外界输入总能量、弹性变形能、耗散能、塑性变形能等参数的演化特征及相互关系,研究结果表明:不同分级循环加卸载作用下,蜂窝的初始峰值强度和平台应力与卸载过程蜂窝弹性能的释放程度有关;3种不同分级循环加卸载模式下外界输入总能量、蜂窝的弹性变形能和塑性变形能随着加卸载梯级增大呈现非线性增加的趋势,耗散能在前三级循环作用下随着加载次数增加而减小,在最后一级循环中循环载荷上限较大,扰动效应强于强化效应,耗散能呈现相反趋势;提升循环载荷上限,蜂窝内部损伤增加,且越接近蜂窝初始峰值强度,蜂窝的损伤越严重;同时提升循环载荷下限,蜂窝弹性能释放较少,损伤加剧。

In order to examine the effects of cyclic loading and unloading paths on the energy evolution of hexagonal honeycomb,three different graded cyclic loading and unloading tests were conducted.These tests aimed to reveal the evolution characteristics and interrelationships of total external input energy,elastic deformation energy,dissipation energy and plastic deformation energy under different graded cyclic loading and unloading modes.The findings show that the initial peak strength and platform stress of the honeycomb are influenced by the release of the elastic energy during the unloading process.The total external input energy,elastic deformation energy and plastic deformation energy of the honeycomb exhibit a nonlinear increase as the number of unloading levels rises.However,the dissipation energy decreases with the number of unloading levels in the first three cycles,and the upper limit of the cycle load is larger in the last stage.The disturbance effect is stronger than the enhancement effect,resulting in an inverse trend in the dissipation energy.As the upper limit of the cyclic load is elevated,the damage inside the honeycomb increases,with the severity increasing closer to the initial peak strength of the honeycomb.Furthermore,raising the lower limit of the cyclic load leads to a reduced release of elastic energy and amplifies the level of damage.