Sudden failure is a type of failure that occurs for a short time, is very difficult to prevent, and happens instantaneously due to abnormal loads such as those induced by the impact of a vehicle colliding with the structure, or those triggered by an explosion. Therefore, prediction of such events is necessary in order to make use of the structures for a longer time. In this thesis, to determine the effects of sudden failure of members on the dynamic response of steel trusses, a meshless numerical method based on the use of exponential functions called “the step-by-step time-weighted residual method” has been used. The main idea of this method is to use pre-integration relationships along with weighted satisfaction of equilibrium equations in successive time steps. In this method, by dividing the computational domain into several subsets, the acceleration field in each time step is considered as a combination of an unknown function, in terms of the spatial variable, and a series consisting of exponential base functions satisfying the strong form of the governing equation. In this method, the initial conditions are accurately satisfied and the equilibrium equations are approximately satisfied using the weighted residual method. Boundary conditions are also satisfied at both ends of each element and at the end of each time step. In this study, using the step-by-step time-weighted residual method, the dynamic response of several steel truss models under sudden failure of members, for different scenarios of member removal, has been eva‎luated numerically. in this process, by having the displacement values of nodes and elements of a truss in time domain, the changes in the axial forces of the elements, in time-space at each time step, are calculated and by defining the mechanism of sudden failure of members, according to their ultimate capacity before failure, the behavior of the structure after removed of the failed member is examined.

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مجتبي ازهري، حسين عموشاهي