Internal Explosion Load Characteristics Analysis And Simplified Models In Blast Resistant Chamber

Blast resistant chamber is a kind of reinforced concrete structure that can produce or store antiknock risk items and withstand internal explosion.With the development of civil explosive industry in China,blast resistant chamber has been widely used,It is of great significance to study the load propagation law and simplified model of explosion action in blast resistant chamber for improving the explosion-proof standard of blast resistant chamber and improving the anti-explosion performance of building structure.In this paper,The AUTODYN software was used to establish the model of reinforced concrete blast resistant chamber under various working conditions,analyze the load law and structural response of indoor explosion target wallboard,and put forward a simplified model of internal explosion load based on equivalent failure principle of target wallboard.The main research contents and achievements of this paper are as follows:(1)The AUTODYN software was used to establish the numerical model of explosion in the blast resistant chamber to simulate the interaction process between the indoor explosion shock wave and the blast resistant chamber,and the explosion test in a confined space and the anti-detonation test of four sides fixed support plate were simulated and verified.The results show that the time-history curve of overpressure,the peak value of structural displacement and the cloud image of structural failure obtained by numerical simulation are in good agreement with the experimental results,and the numerical simulation method can be used to analyze the characteristics of internal explosion load and structural response accurately.(2)A series of indoor explosion numerical models were established for parameter analysis to research the influence of TNT mass,height of TNT above ground,area of detonation vent and room size on the law of indoor explosion load and structural displacement response characteristics.The results show that when the explosion occurs in symmetry axis position of the blast resistant chamber,the peak value of overpressure decreases with the increase of proportional distance,but increases at the boundary of the wall due to reflection and superposition effect,the minimum value occurred at about200 mm to 500 mm from the wall panel boundary.Under indoor blast load,the front face of the target wallboard is shear failure with four sides fixed support,and the back face is central bending failure.With the increase of TNT mass,the peak value of overpressure is larger and the duration is shorter.The wallboard oscillation peak is larger and the period is longer.The damage degree of near-surface explosion is stronger due to the influence of reflection superposition and Mach wave.The vent is beneficial to reduce the effect of indoor explosion,the overpressure peak is less affected,and the displacement of wall panel is more affected.The larger the size of the blast resistant chamber,the lower the absolute bearing capacity of the target wallboard,and the longer side direction is easier to damage than the short side direction.(3)Based on a large number of numerical simulation results and the principle of equivalent failure of target wallboard,when the explosion occurs in the blast resistant chamber,a simplified model chart of the explosion load acting on the target wallboard is established,which can consider different TNT mass,arbitrary explosive position,room size,concrete strength grade and wall thickness parameters.The error of the simplified model is less than 5%,which can be applied to engineering practice.