摘要
利用数值分析方法,系统研究了爆炸冲击荷载作用下弹性支撑对拱结构动力特性和动力响应的影响。研究表明:弹性支撑使拱结构自振频率减小,随着弹性支撑刚度系数的增加,各阶频率逐渐增大,其中对低阶频率的影响比高阶频率大;弹性支撑临界刚度系数是弹性支撑拱结构动力特性的分界点,此时结构第一阶、第二阶的频率几乎重合,出现模态转向;弹性支撑并不总是具有缓冲减振的效果,弹性支撑刚度系数较小时,缓冲减振效果较好,但会引起较大的拱脚竖向位移,在工程实际中可能并不适用;弹性支撑刚度系数较大时,在爆炸冲击消失以后,由于非线性振动等因素的影响,会出现振动增强,尤其当弹性支撑刚度系数接近弹性支撑临界刚度系数时,结构振动增强最为剧烈,此时设置阻尼支撑可消除振动增强。本文结果表明应综合设置刚度系数较大的弹性支撑和阻尼支撑以提高结构的抗爆承载能力。
Using numerical analysis method, effects of the elastic supports on the arch structures dynamic characteristics and responses are studied. Results obtained show that the elastic supports decrease the natural frequencies of the structure. Each order frequency increases with the increase of the elastic supports stiffness. The critical stiffness is demarcation point of the dynamic characteristics. Both the first and second frequencies are very close and the modal shift occurs. Elastic supports are not always performing buffer damping effect. When the stiffness coefficient is small, buffer damping effect is good, but it will cause a large vertical displacement at the arch foot. So the small stiffness may be not applied in engineering practice. When the stiffness coefficient is large, the vibration rebound will occur due to the nonlinear vibration and other factors after the explosion shock disappears. Especially if the stiffness closes to the critical stiffness, the vibration rebound occurs most severe. Setting damping supports can eliminate vibration rebound. The elastic supports with large stiffness and the damping supports should be set to improve the anti-knock bearing capacity of the arches.
出处
《应用力学学报》
CSCD
北大核心
2017年第4期679-684,共6页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金(51308540
51208506)
关键词
爆炸冲击
弹性支撑
拱结构
动力响应
explosion shock
elastic supports
arch structures
dynamic responses
