Deformation and failure of thin domed-scored metallic disc under impulsive loading

Abstract

This paper presents the structural deformation and failure of a thin domed-scored metallic disc (SMD) applied at the bottom of a pressurized rocket silo which needs to withstand a storage pressure and undergo instantaneous rupture under an impulsive pressure. Initially, the large deformation and rupture of a flat-thin SMD subjected to a pressure impulse is numerically studied and validated with experimental results. Subsequently, the behavior of a domed-thin SMD is investigated for the aforementioned loadings in the rocket silo. The influence of loading rates ( P · ) , score depth and width-to-disc thickness ratio (t 1 /t and b/t), diameter-to-disc thickness ratio (D/t), dome height-to-disc diameter ratio (H/D), score length-to-disc radius ratio (l/R), score pattern, and score geometry on the deformation and failure response of the domed-thin SMD is investigated. The studies demonstrate that (1) the failure initiation point shifts from 1/4th radius to the disc center for loading rates > 10 MPa/s; (2) under impulse loading, the responses are (i) sensitive to the loading rates up to 100 MPa/s, (ii) sensitive to score’s depth, only up to half the disc thickness and insensitive to score’s width, (iii) unaffected for number of scores N > 6, (iv) stabilized for l/R > 0.4, and (vii) almost the same for semi-circular, rectangular and triangular score geometries; (3) the failure do not initiate and propagate along all scores for N > 10 in the disc; and (4) behavior of the domed SMD approaches to that of a spherical dome for H/D > 0.3.