Numerical Simulation Of Masonry Walls Under Blast Loading

Masonry wall is widely used in engineering due to its good economy performance. Either as the main structural member of masonry buildings, or as the envelope components of frame structure and frame-shear wall structure, it is still widely used in our country. Compared with reinforced concrete structures, masonry wall is more likely to produce high-speed debris under high-speed impact load explosion because of its much more brittleness, which is dangerous to building users. Therefore, since the sept.11 terrorist attacks, with the more and more blast attacks, government and research institutions around the world have carried out extensive and intensive research about the behavior of masonry walls under blast loading. Because masonry walls are widely used as building envelope component of reinforced concrete structures in cities and towns, it is particular necessary to carry out research of its behavior under blast loading. In recent decades, with the development of computer technology and finite element technology, it is possible to conduct structural analysis under blast loading with finite element analysis software for. Based on the above background, ANSYS/AUTODYN software and its comparison to data of the Impact of Drop Hammer Machine test of masonry walls.In this thesis, he dynamic response, failure process,debris eject rule of the 120 mm masonry wall,240 mm masonry wall, and reinforcement 240 mm wall has been studied. The main research work is as follow.The explosive load distribution rule of masonry wall under close range blast load is investigated by using finite element analysis software ANSYS/AUTODYN. The simulation results shows that explosive impact load is extremely uneven when the explosion distance is short. With the increase of explosion distance, the impact load distributions is more evenly. Increasing the critical distance can significantly reduce explosion overpressure load.The dynamic response and failure process of 120 mm wall, 240 mm wall, and reinforcement 240 mm wall under close range blast load is studied with numerical simulation. The results show that all 3 walls tend to collapsed failure under the close range hand-carried explosives, the destruction laws of masonry walls are similar, but there are differences in the extent of damage. The ejecting speed of 240 mm wall and strengthened 240 mm wall declined obviously compared with 120 mm masonry wall. Because of the consolidated film of PU, the ejecting speed and displacement of strengthened of 240 mm wall declined significantly. In addition, the relationship between ejecting speed and scaled distance is similar to the relationship between scaled distance and peak overpressure.The simulation analysis results meet the Impact of Drop Hammer Machine tests' results quite well on the failure process of masonry walls. Besides, the loading rate of drop hammer impact test tends slower significantly than the explosive impacts'.