Numerical Simulation of Dynamic Response and Collapse for Steel Frame Structures Subjected to Blast Load

The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA. The multi-material Eulerian and Lagrangian coupling algorithm was adopted. A flu-id-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground, multiple ALE element for simulating air and TNT explosive material. Numerical simulations of the blast pressure wave propagation, struc-tural dynamic responses and deformation, and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed. The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure. The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation. The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic defor-mation subjected to intensive blast waves, and columns lost carrying capacity, subsequently lead-ing to the collapse of the whole structure. The approach coupling influence between struc-tural deformation and fluid load well simulated the progressive collapse process of structures, and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load.     

Numerical Simulation of Dynamic Response and Collapse for Steel Frame Structures Subjected to Blast Load

The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA.The multi-material Eulerian and Lagrangian coupling algorithm was adopted.A fluid-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground,multiple ALE element for simulating air and TNT explosive material.Numerical simulations of the blast pressure wave propagation,structural dynamic responses and deformation,and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed.The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure.The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation.The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic deformation subjected to intensive blast waves,and columns lost carrying capacity,subsequently leading to the collapse of the whole structure.The approach coupling influence between structural deformation and fluid load well simulated the progressive collapse process of structures,and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load.     

Simulation of the Response of Glass Window Under Blast Load

In the investigation of accidental explosion scene, the damage on the glass is one of the typi-cal traces which can be used to decide the characteristic of the explosion source. To analyze the re-sponse of glass under the blast load, a numerical model was developed. In the model, the brittleness glass model was adopted. A‘node release’method, which had some special merits compared with the erosion method was used to simulate the rupture of the glass In the calculation, several problems which play major role in the response of the glass were discussed. The velocity and the displacement of the glass fragment were two major factors. The numerical results are very helpful for the design and hazard assessment.     

Damage assessment for buried structures against internal blast load

The soil-structure interaction (SSI) decoupling is applied to simplify buried structure against internal blast load as spring effect. Shear failure, bending failure and combined failure modes are considered based on five transverse velocity profiles for the rigid-plastic structural element. The critical equations for shear and bending failure are derived respectively. Pressureimpulse diagrams are accordingly developed to assess damage of the buried structures against internal blast load. Comparison is done to show influences of soil-structure interaction and shear-to-bending strength ratio of a structural element. A case study is conducted to show the application of damage assessment to a reinforced concrete beam element of buried structure.     

用Excel完成高炉鼓风机选型的计算

本文简述了实际工作中编写的高炉鼓风机选型计算程序及其完成的功能和使用方法。给出具体应用示例并总结归纳其特点。     

焊瓶钢板缺陷分析及改进措施

文章通过检验废品,分析生产工艺缺陷,找出HP295成瓶率低的原因,并提出相应的改进措施.     

高可靠的双机热备控制系统

运行相同控制程序的配量相同的控制主机,通过实时数据交换模块形成互为热备份的冗余结构,利用可以自动切换的冗余配置的通讯网络以及冗余的现场控制单元,构成完整的双机热备控制,可极大提高控制系统的可靠性和安全性,满足如大型火电站、核电站、易燃易爆等特殊场合的控制要求.     

浅谈对低温地板辐射采暖的几点认识

本重点介绍低温地板辐射采暖的发展、特点及施工中的注意事项。     

Numerical Calculation of Concrete Slab Response to Blast Loading

In the present paper, a dynamic plastic damage model for concrete has been employed to estimate responses of a reinforced concrete slab subjected to blast loading. The interaction between the blast wave and the concrete slab is considered in 3D simulation. In the first stage, the initial detonation and blast wave propagation is modelled in 2D simulation before the blast wave reaches the concrete slab, then the results obtained from 2D calculation are remapped to a 3D model. The calculated blast load is compared with that obtained from TM5-1300. Numerical results of the concrete slab response are compared with the explosive test carried out- in the Weapons System Division, Defence Science and Technology Organisation, Department of Defence, Australia.     

Enhancing rice resistance to fungal pathogens by transformation with cell wall degrading enzyme genes from Trichoderma atroviride

INTRODUCTION Rice sheath blight (Rhizoctonia solani) and rice blast (Magnaporthe grisea) are two serious plantdiseases in China. Rice cultivars with high level and durable resistance to these two pathogens are noteasy to obtain by traditional breeding methods due to the lack of germplasm resistant to R. solani and the high genetic diversity of M. grisea. Cell wall degrading enzyme (CWDE) genes from biocontrol fungi belonging to the genus Trichoderma have been demonstrated to encode …