In this paper, the large inelastic deformation and failure mechanism of single and multi-layered circular plates under repeated uniform impulsive loading were studied. The ballistic pendulum was used to conduct a series of experiments (67 experiments) on aluminum alloy plates with different structural configurations. Three different layering configurations including single, double, and triple-layered plates made of the same material were considered and tested for the range of charge masses from 1.5g to 12.5g up to five times for repeated loading. The experimental results indicated large plastic global deformation with thinning happening at the clamped boundary and also tearing for some experiments. The results also represented that the maximum permanent deflections of plates were increased by the increase of the charge mass and the number of blast loads. On the other hand, the progressive deflection of the plates at the center was decreased exponentially with increasing the number of blasts. Furthermore, in the numerical modeling section, the Group Method of Data Handling (GMDH) neural network was used to present a mathematical model based on dimensionless numbers to predict the maximum permanent deflection of single and multi-layered circular plates under repeated impulsive loading. In order to increase the prediction capability of the proposed neural network for this process, the experimental data were divided into two training and prediction sets. Good agreement between the proposed model and the corresponding experimental results is obtained and all and 77% of data points are within the <10% error range for single and multi-layered plates, respectively.

In the last decade, the gas mixture detonation forming (GDF) method has been introduced as a novel and alternative method instead of other high-velocity forming (HVF) methods such as explosive method. Due to the lack of research in this field, the present study investigates the free and die forming of circular metallic plates under gas mixture detonation loading. In this series of experiments, steel plates with thicknesses of 1, 2, and 3mm, aluminum plates with a thickness of 3mm, and brass plates with a thickness of 1mm were used. Furthermore, the test specimens were loaded in the impulse range of 4.12 to 54.68N·s. For better comparison, the same areal density condition was considered to compare the results of steel, aluminum, and brass plates under the same loading conditions. Experimental results showed that using a die with an apex angle of 60° leads to the decrease of the maximum permanent deflection by 14.8, 20.2, and 21.4% in 1, 2, and 3mm steel plates, respectively. Under the same loading and areal density conditions, for free forming, the use of aluminum and brass plates lead to increasing the maximum permanent deflection by 19.4 and 13.1% compared to the steel sample, respectively. However, in die forming, these values were 5 and 2%, respectively. Also, the comparison of the results for aluminum and brass plates shows that the using die forming reduces the maximum permanent deflection of the specimen by 12.1 and 10.6%.