爆炸载荷下薄板异常动力响应模式及载荷特征影响研究

STUDY ON THE ABNORMAL DYNAMIC RESPONSES OF THIN PLATE SUBJECTED TO EXTREME LOADING AND INFLUENCES OF LOADING CHARACTERISTICS

薄板在爆炸冲击载荷作用下的动力行为复杂,具有大变形、瞬时性、高度非线性等特点.当冲击波冲量较小时,薄板容易发生异常动力响应.然而,爆炸冲击波特征对薄板异常动力响应的影响尚不明晰.为此,本文采用经实验数据验证的自主开发爆炸载荷模型,首先成功地模拟了方形薄板的反直观异常动力响应;然后通过数值仿真研究了冲击波负压描述方法、正压衰减系数等对薄板异常动力响应的影响;最后,发现了在距离当量比一定时,随着爆炸距离的增加薄板依次发生继发直观、反直观、混合、始发直观四种行为模式,并分析了不同行为模式下响应历程与塑性耗散能之间的关系.

The dynamic behavior of thin plate under impulsive loading is of high complexity,characterized by large deformation,instantaneity,and severe nonlinearity.When a thin plate is subjected to a shock wave of low impulse,abnormal dynamic response is prone to occur.However,effects of loading characteristics on the abnormal dynamic response of thin plate are not clear.An impulsive loading model validated by experimental data is successfully used to simulate the counter-intuitive response of a thin square plate,and then the effects of negative pressure and decaying parameter on the abnormal dynamic response are studied.Finally,when the stand-off distance increases with a fixed scaled distance,four different modes-secondary intuitive,counter-intuitive,mixed,and initial intuitive modes-are found.The relationship between the different dynamic behavior modes and the plastic dissipation energy is examined.