振动与冲击
振動與遲擊
진동여충격
JOURNAL OF VIBRATION AND SHOCK
2015年
2期
119-124,133
,共7页
冲击荷载%动力稳定性%判定准则%参数分析
遲擊荷載%動力穩定性%判定準則%參數分析
충격하재%동력은정성%판정준칙%삼수분석
impact load%dynamic stability%discriminant criterion%parametric analysis
针对冲击荷载不同于地震作用,而常规动力稳定性判定准则不适用问题,阐述求解冲击问题的基本理论及冲击荷载取值;据冲击荷载特性提出适合冲击碰撞问题的单层网壳结构动力稳定性判定准则;选 K6型单层网壳结构模型,利用非线性有限元软件 ANSYS /LS -DYNA 进行结构冲击作用下动力稳定性分析,通过大量算例,分析其在不同冲击物质量比及速度作用下全过程动力响应,结合动力响应模式获得冲击荷载作用下单层网壳动力失稳的临界能量区域,并从矢跨比、跨度、杆件截面三方面对结构进行参数分析。结果表明,基于网壳动力响应模式与冲击能量相结合方法对单层网壳进行动力稳定性判定合理;结构刚度越小,冲击作用下动力稳定性越差;加大主肋利于提高结构动力稳定性。
針對遲擊荷載不同于地震作用,而常規動力穩定性判定準則不適用問題,闡述求解遲擊問題的基本理論及遲擊荷載取值;據遲擊荷載特性提齣適閤遲擊踫撞問題的單層網殼結構動力穩定性判定準則;選 K6型單層網殼結構模型,利用非線性有限元軟件 ANSYS /LS -DYNA 進行結構遲擊作用下動力穩定性分析,通過大量算例,分析其在不同遲擊物質量比及速度作用下全過程動力響應,結閤動力響應模式穫得遲擊荷載作用下單層網殼動力失穩的臨界能量區域,併從矢跨比、跨度、桿件截麵三方麵對結構進行參數分析。結果錶明,基于網殼動力響應模式與遲擊能量相結閤方法對單層網殼進行動力穩定性判定閤理;結構剛度越小,遲擊作用下動力穩定性越差;加大主肋利于提高結構動力穩定性。
침대충격하재불동우지진작용,이상규동력은정성판정준칙불괄용문제,천술구해충격문제적기본이론급충격하재취치;거충격하재특성제출괄합충격팽당문제적단층망각결구동력은정성판정준칙;선 K6형단층망각결구모형,이용비선성유한원연건 ANSYS /LS -DYNA 진행결구충격작용하동력은정성분석,통과대량산례,분석기재불동충격물질량비급속도작용하전과정동력향응,결합동력향응모식획득충격하재작용하단층망각동력실은적림계능량구역,병종시과비、과도、간건절면삼방면대결구진행삼수분석。결과표명,기우망각동력향응모식여충격능량상결합방법대단층망각진행동력은정성판정합리;결구강도월소,충격작용하동력은정성월차;가대주륵리우제고결구동력은정성。
Unlike for the case of seismic action,the conventional dynamic stability criteria are no longer applicable for the case of impact load.The basic theory of solving the impact problem and the problem of how to take resonably the value of impact load were expounded.According to the impact load characteristics,the dynamic stability criterion suitable for impact collision problem of single-layer reticulated shell structure was proposed.Taking a K6 single-layer reticulated shell model as an object,the dynamic stability analysis under impact was carried out by using the nonlinear finite element software ANSYS /LS-DYNA.The whole process of dynamic response under the action of different quality and speed of impact loads was analyzed.The critical energy region of dynamic instability of the single-layer reticulated shell under impact loads was obtained based on the dynamic response model.The dynamic stability under earthquake was also analysed in order to get the instability critical load which was then compared with that under impact action.From the aspects of rise-span ratio,span and bar cross-section,a parameter analysis was carried out.The results show the dynamic stability discriminant method for single-layer reticulated shell structures,which combines the dynamic response model with the impact energy is reasonable.The smaller the structure stiffness,the worse the dynamic stability under impact load. Increasing the main bar section is most conducive to improve the structure dynamic stability.