PSI - Issue 14

S.Thalapathi Raj et al. / Procedia Structural Integrity 14 (2019) 395–402 S Thalapathi Raj / Structural Integrity Procedia 00 (2018) 000 – 000

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1. Introduction

Modelling of structural damages is a tool for making blast damage assessments resulting from an explosion on a localized area. This can be used as a damage/ injury assessment tool to determine the amount of blast damage/injury done to individual structures/ persons in a certain geographical area due to the detonation of explosives at ground level or at a specified height above the ground. Many of the Defence, S&T and Space research organizations are using explosive as a key component in their various stages of Design & Development of explosive driven systems and Shock & Detonics studies. As these activities are hazardous and risky in nature it is mandatory to have suitable engineering control measures and Risk Assessment methodology to protect the man, material, equipments and buildings from the accidental damages. The prediction of hazard level and other parameters can be done by using H igh Ex plosive D amage A ssessment M odeling (HEXDAM) software. This paper helps to predict the structural damages of an experimental bay building of a space research organization using HEXDAM modelling software when the facility is subjected to explosive testing of quantity of 500 gm Equivalent TNT. The modelling helps to predict the blast parameters at various points and the structural damages caused to the structures with in a facility which will help in getting safety clearance for the facility. The basic outputs of structural damage analysis are designed to provide data such as before/after blast display; damage/injury table; damage vs distance; pressure contours; damage/injury contours and the data tables for overpressure, dynamic pressure and damage/injury at each grid point.  To predict the human and structural effects of explosions  To ensure worker’s safe ty and minimize facility damage  The degree of risk can be minimized by ensuring such a way that the adjacent explosives stocks and facilities & personnel near to the explosives stocks are located at a pre-determined, practical standard distance. Specialized explosion modeling software allows facilities to input potential explosion scenarios based on the type of materials they use and store as well as the structural components of the building itself 2. Modelling Methodology This Structural Damage analysis software has the capability to model an unlimited number of structures, each with different dimensions and structural properties. It utilizes widely accepted dynamic pressure and overpressure curves to predict the pressure level at each structure / persons location. 2.1 Steps involved in HEXDAM Analysis 1) The first step in modelling is to specify a primary explosion with in or around a facility consisting of one or more structures and personnel. 2) In HEXDAM user can place an explosion within a layout. The explosive content was converted into equivalent TNT weight as follows. First the bare charge equivalent is calculated using the following formula. Bare charge equivalent = …………………… (1) And the equivalent TNT value is calculated with the respect to the explosive factor. For example, the TNT equivalent for Explosive Type I is 1.5. 3) Then the user must make the layout of the building/facility and shall provide the input data about the structures 4) Models have been pre-programmed for standard types of structural elements. 5) The model can predict the pressures received by each structure and person in the facility and then calculate the damage/ injury to each structure and person based on the magnitude of the pressure received and the ability to withstand the pressure.