Response of a Thin Flat Scored Metallic Disc Under Pressure Impulse

K. Gopinath; V. Narayanamurthy; Y.V.D. Rao

doi:10.14429/dsj.72.17755

K. Gopinath Department of Mechanical Engineering, BITS Pilani-Hyderabad, India- 500 078 https://orcid.org/0000-0001-8060-2295
V. Narayanamurthy Directorate of Systems Integration, Research Centre Imarat, Hyderabad, India - 500 069 https://orcid.org/0000-0002-7194-5242
Y.V.D. Rao Department of Mechanical Engineering, BITS Pilani-Hyderabad, India- 500 078 https://orcid.org/0000-0003-3452-5115

DOI: https://doi.org/10.14429/dsj.72.17755

Keywords: Flat scored metallic disc, Score geometry, Score pattern, Large deformation, Failure, Impulsive load, Explicit finite element analysis

Abstract

This paper presents the large deformation, and failure response of a thin flat scored metallic disc (FSMD) subjected to a pressure impulse as experienced in a break-away disc or an explosion vent. The response of this thin FSMD is numerically simulated for a loading rate and validated with an experiment, where a good agreement is found on plastic strains, burst pressure, and deformation pattern. The loading rate and several geometric parameters of FSMD significantly influence its response. Therefore, the influence of loading rate ( P& ), score depth and width-todisc thickness ratio (t 1 /t and b/t), diameter-to-disc thickness ratio (D/t), score length-to-disc radius ratio (l/R), score pattern, and score geometry on the deformation and failure response of the thin FSMD is thoroughly investigated. The studies demonstrate that 1) the failure initiation point shifts from disc centre to between 1/5th and 1/3rd radius for loading rates ≤ 25 MPa/s; 2) the responses such as burst pressure, burst time, central deflection, and equivalent strain are i) sensitive to the loading rates up to 100 MPa/s, ii) sensitive to score’s depth, only up to 0.6t and insensitive to score’s width, iii) significantly unaffected for the number of scores N > 8, iv) stabilised for l/R > 0.5 and D/t > 250, v) almost the same for semi-circular, rectangular and triangular score geometries, and vi) very minimal for the number of scores N = 3; and 3) the failure do not initiate and propagate along all scores for N > 4 in the disc.