The Loading Discrepancies in CONWEP and Fluid-structure Interaction Methods and the Dynamic Response Characteristics of Masonry Wall

The dynamic response behavior of masonry walls under large equivalent blast loading is investigated using a full-scale numerical model of windowed and windowless double-sided masonry walls, which is etablished by a cohesive zone method (CZM). A field experiment with a TNT equivalent of 500 kg and blast distance of 13 m is used as the basis for the study. The numerical simulations are carried out using two blast load application methods, conventional weapons effects program (CONWEP) and coupled-Eulerian-Lagrangian (CEL). The results indicate that the peak incident overpressures calculated by CONWEP and CEL methods are consistent with the experimental result compared to the swept overpressure data measured at the ground surface. However, the arrival time calculated by CEL method is 7. 1% earlier than the test, and the rise time is four times that of the test. On the other hand, the overpressure decay calculated by CONWEP method is slower, and the positive pressure time and impulse volume are 50. 7% and 42. 56% of the test, respectively. It can be seen by comparing the load curve differences of the two blast loading methods that the rise time of overpressure-time curve calculated by CONWEP method is always constant, but the arrival time and rise time of shock wave calculated by CEL method are affected by the distance from explosive source and mesh size, and the larger the distance from explosive source and mesh size are, the longer the rise time is. The differences in the spatial and temporal distributions of shock wave flow field are reflected in the ideal hemispherical shape of wavefront calculated by CONWEP method and the oblate spherical shape of wavefront loaded by CEL method. For the reflected overpressure peak applied to the wall, the peak of CONWEP method loading is larger in each region and the decay rate is the same in all directions, while the decay rate loaded by CEL method in the y (vertical) direction is greater than that in the z (horizontal) direction. In the study of progressive damage law of wall, CEL loading can simulate the local damage characteristics of the wall more accurately. Moreover, the final damage pattern of the wall under CEL loading is closer to that of the test, while CONWEP method has a greater degree of damage. © 2023 China Ordnance Society. All rights reserved.