摘要
钢管混凝土构件的安全设计除了需要分析常规荷载外,还要分析偶然荷载,侧向冲击是偶然载荷类型之一。根据材料受力特点,混凝土选择RHT本构模型描述,钢选择John-Cook本构模型,采用动力有限元软件AUTODYN数值分析了侧向冲击条件下,撞击物质量、撞击速度、撞击位置和钢管混凝土端部约束状态对混凝土损伤演化规律的影响。研究发现混凝土损伤起始于碰撞位置,然后向下端、约束端发展,在损伤发展过程中,约束端及挠度最大区域也形成较严重的损伤带。碰撞部位的混凝土严重损伤区主要位于上部;约束端严重损伤区的分布特征与约束类型相关:简支约束端的损伤区位于约束区域内,而固支约束端的损伤区位于约束端外毗邻区域;挠度最大区域的损伤区分布受撞击位置及端部约束类型影响。混凝土内能随撞击物速度、质量及撞击位置偏离中心距离的增加而增加。在撞击作用区域,钢管混凝土径向产生较大塑性变形,钢管混凝土构件抗压性能下降。本研究对于评估钢管混凝土受侧向冲击作用后的稳定性及承载力具有重要意义。
Besides the conventional loads, the accidental loads should be considered on the safety design for the concrete filled steel tube （CFST）, and one of accidental events is the lateral impact. According to the stress state of concrete and steel, the constitutive model of RHT is used for the concrete, and that of John-Cook is used for the steel. The damage evolution rules for the inner concrete are studied using the dynamic finite element software of AUTODYN, in the conditions of the impact varied with mass, velocity and the position contacted with CFST, and different restrained types at the ends. The results show the damage begins from the contact position between the impact and the CFST, and develops toward the bottom of an impact position and the restrained end. During the interaction between the impact and the CFST, the strong damage zones are also generated near the restrained end and the zone of maximum deflection. There is a strong damage zone in the upper concrete near the impact position; and the damage characteristics at the end are decided by the restrained type： the strong damage zone lies in the restrained region for the simple support end, and lies outer for the clamped support; the damage distribution in the maximal deflection is controlled by the relative position between the impact and the center of CFST and the restrained type at the end. The inner energy absorbed by concrete increases with velocity, the weight of impact,and the horizon distance between the impact position and the center of CFST. There is a larger plastic strain near the impact position, which may decrease the capacity of resist compression for the impacted CFST. The results are significant to assess the residual capacity of CFST suffered from the lateral impact.
出处
《工程力学》
EI
CSCD
北大核心
2013年第B06期267-272,共6页
Engineering Mechanics
基金
中央级公益性科研所基本科研业务费专项资金项目(20120919)
中国博士后科学基金项目(20110490344)
关键词
工程力学
钢管混凝土
侧向冲击
混凝土损伤
损伤演化
engineering mechanics
concrete filled steel tube
lateral impact
concrete damage
damageevolution
