Study of Crater in the Gobi Desert Induced by Ground Explosion of Large Amounts of TNT Explosive up to 10 Tons

Explosion craters on the ground surface induced by contact or near-field explosions have important implications, which can be used to assess blast consequences, guide the design of the explosion, or develop a protective strategy. In this study, to understand the crater characteristics induced by the contact explosion of large weight explosives, four field contact explosion tests were conducted on the surface of the Gobi Desert with large TNT charge weights of 1 ton, 3 tons, and 10 tons (test conducted twice). Cratering on the ground surface generated by large amounts of explosives was measured and evaluated, including the shape, depth, and diameter. A fine-mesh numerical model was developed and validated on the AUTODYN software platform, and a detailed parametric study was performed on the resulting craters. The effects of sand and gravel density, initiation method, shear modulus, and failure criteria were analyzed and discussed. An energy conversion coefficient was determined, and the corresponding theoretical equations were derived to predict the dimensions of the craters resulting from the large weight contact explosion. The calculated cratering characteristics were consistent with previous data and hence can be used in future engineering applications.

Strength analysis of warship hull’s bottom loaded by the pressure wave from a non-contact explosion of sea mine explosion of sea mine

The study was based on the analysis of stamina of steel flat bottom section of transport warships, burdened by the spherical pressure wave from the non-contact explosion of TNT at a distance of 20 m under the keel. This study aims to determine the TNT mass required to break the hull. The task was solved by finite element method (FEM) explicite using CAE program [1], in which the hull’s bottom was modelled as thin shell space. The hull’s burden with pressure wave was modelled as a pressure impulse specified by the formula introduced by T.L. Geers, K.S. Hunter and R.S. Price [2]. To describe the material properties, considering high-speed strain, the Johnson-Cook model was used [3]. Therefore, the main goal of the hereby paper is to present how to correctly model the impact of large, concentrated masses of the ship’s equipment on its hull. The study presents the results of the calculated stress and strain states of the analysed section of the construction of the hull.

Safety Evaluation of Arch Dam Subjected to Underwater Contact Explosion

The stability of an arch dam can be significantly damaged by an extreme underwater explosion. This study proposed a damage index for assessing the degree of local damage of an arch dam after the dam was subjected to an underwater explosion. The damage index was applied to assess local damage at the middle part of the dam, surcharge holes, and abutment. A model was developed to evaluate the stability of the entire dam based on the spatial distribution of damage and the damage on the base interface. Results showed that local explosion damage at flood discharge holes or abutments might cause instability of the arch dam. When the contact explosion action location is on the abutment, it only needs 310 kg to cause the overall damage of the arch dam, while when the action location is on the middle part of the dam, the quantity of explosive required is 2800 kg.

Ship Blast Analysis

Naval vessels and Submarines structures in their fighting role are susceptible to explosion of torpedoes, mines, TNT etc. The damage inflicted by Contact explosion consists of direct shock wave damage to hull, whipping damage to keel and mechanical damage to onboard equipment and associated systems. The order to design a shock resistant structure, it is important to simulate these structures and loads and then subsequently analyze the same to predict the response (as performing experiments would be expensive). The TNT (Trinitrotoluene) explosion analysis of large structures like ships could be considered as one of the most complicated numerical analysis. Loads can be calculated by using published empirical formulas, which are complicated if calculated the large structure. By using of the FE Software ANSYS, backed up with in the developed software, for Explosion analysis of structures.

Damage Characteristics of Polymer Plates under the Impact of the Near-Field and Contact Underwater Explosion

In order to study the damage characteristics of polymer plates under the impact of the underwater explosion, the underwater contact and near-field explosion tests of polymer plates were conducted using different explosive quantities. In this paper, eight polymer plates with the size of 500 mm × 500 mm × 60 mm were made, and eight groups of explosion tests were carried out by using the rock emulsion explosive and nonconductive detonators. The damage modes and spatial distribution characteristics of the polymer plate generated by the underwater contact and near-field explosion impact with different explosive quantities are compared and analyzed. In addition, the characteristics of the shock wave propagation in the plates are investigated. It can be observed that the main damage mode of polymer plate is overall damage under the contact underwater explosion. For the near-field explosion, the main damage mode changes to overall failure, and the damage of contact explosion to polymer plate is greater than that of underwater near-field explosion. The polymer plate can reduce and delay the shock wave effectively, but the effect decreases with the increase of explosive quantity in the underwater contact explosion.