Numerical simulations of ceramic target subjected to ballistic impact using combined DEM/FEM approach

Influence of thickness and projectile shape on penetration resistance of the compliant composite

Ballistic impact of a steel projectile on armour steel plate is examined by numerical simulations using 3-D nonlinear dynamic explicit finite element code ANSYS LS-DYNA. Simulations are attempted using a simple strain rate dependent plasticity model that can capture large strain, strain rate hardening and fracture encountered at high velocity ballistic impacts. Initial simulations are carried out for a cylindrical bullet with a semi-spherical nose shape impacting a military vehicle door at two different velocities as a test problem. This is then extended to simulate a real problem of armour piercing shot impact on a thick armour steel plate at ordnance velocity regime. The former is compared with results reported in published literature while the latter is assessed with the experimental findings. The deformation pattern generated in the deformed armour plate, residual projectile velocity and displacement of the projectile are taken as the necessary parameters for evaluating the results of simulation. The study presented in this paper demonstrates the effectiveness of the adopted simple plasticity model to simulate a highly nonlinear phenomenon to reasonably predict the physically measurable impact parameters. Defence Science Journal, Vol. 64, No. 1, January 2014, DOI:10.14429/dsj.64.4521

Numerical Simulation of Ballistic Impact on Armour Plate with a Simple Plasticity Model

Ballistic impact (BI) is a study that deals with a projectile hitting a target and observing its effects in terms of deformation and fragmentation of the target. The Discrete Element Method (DEM) is a powerful numerical technique used to model solid and particulate media. Here, an attempt is made to simulate the BI process using DEM. 1-D DEM for BI is developed and depth of penetration (DOP) is obtained. The DOP is compared with results obtained from 2-D DEM. DEM results are found to match empirical results. Effects of strain rate sensitivity of the material response on DOP are also simulated.

Numerical Simulation of Ballistic Impact on Particulate Composite Target using Discrete Element Method: 1-D and 2-D Models

The bullet-resistant vest (bullet proof vest) is an important accessory to absorb impact energy and stop bullets from penetrating the body. In the present work a sandwich composite structure was designed from different sequential layers of, twinning induced plastic (TWIP) steel, polypropylene – polyethylene (PP-PE) polymer and water for bullet proof vest application. Owing to the difficulty in experimentally testing materials for ballistic impact application, a finite element – smoothed particle hydrodynamic (FE-SPH) coupled simulation was applied for analyzing the impact characteristics of the proposed composite structure. Different structural layers of the composite are simulated to select the most effective thickness of steel/polymer/water layers in energy absorption and penetration prevention. The simulation results displayed that the optimum thickness of the layers are 2 mm steel/20 mm water/2 mm steel , which is able to stop a 9 mm bullet travelling at 360 m/s with less than 10 mm displacement of the inner surface of the composite. This composite is promising and has a great potential in fabrication of effective and light weight bullet proof vest with less expensive materials.

Ballistic Impact Simulation of Proposed Bullet Proof Vest Made of TWIP Steel, Water and Polymer Sandwich Composite Using FE-SPH Coupled Technique

One-dimensional discrete element model for the ballistic impact is used to determine the depth of penetration of a bullet on a thick target. Discrete Element Method (DEM) is a numerical tool where a continuum is modelled as a network of masses connected by normal springs. A one-dimensional discrete element model is developed to obtain the displacements and forces associated with the ballistic impact on a thick target. The depth of penetration of the penetrator into the target is calculated from these DEM results. The simulated results of depth of penetration are found to be in reasonable agreement with the simulation results of other numerical approaches that are available in the literature.

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Simulation of depth of penetration during ballistic impact on thick targets using a one-dimensional discrete element model

The rapid development of the global economy has led to an increased energy demand throughout the world. More than 70% of the world’s energy consumption is from the use of fossil fuels. In the wake of rising global temperatures and increased carbon emissions, policymakers across the globe think about alternate and renewable ways of energy generation, among which wind energy is a promising energy source. Offshore wind turbines are new technologies and are challenging when it comes to their installation in harsh ocean environment as they are subjected to environmental loads caused by wind, wave and currents. These loads are then transferred to foundation. Monopiles are the most common foundations used in offshore wind turbines today and therefore its analysis is important. Monopiles are single large diameter tubular steel piles of diameter 3–7 m driven into the seabed with typical penetration depth of 25–30 m, and are subjected to lateral dynamic loads. Soil structure interaction of monopile is an important aspect to be considered in its design and for the present study, PLAXIS 3D geotechnical software is used for the soil-pile interaction and the corresponding displacement behaviour of the pile under study. The dynamic analysis due to the wave forces on the monopile is carried out using wave data off Gulf of Mannar, near the Tamil Nadu coast, and the embedment length of the pile is varied to study the effect of diameter of pile and embedment length on the displacement characteristics of the pile.

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Soil Structure interaction of Laterally Loaded Piles

Thermal analysis of natural fiber reinforced composites

Discrete Element Method (DEM) is an explicit numerical scheme to model the mechanical response of solid and particulate media. In our paper, we are introducing Quadrilateral Discrete Element Method (QDEM) for the simulation of the separation of elements in fixed beam subjected to impact load. QDEM results are compared with other DEM results available in literature. Impact loads include two cases: (a) a half sine wave and (b) a penetrator hitting the fixed beam. Separation criteria used for the discrete elements is maximum principal stress failure criteria. In QDEM, convergence study for the response of fixed beam is obtained using MATLAB platform. Validation of quadrilateral elements in fixed beam is being carried out by comparing the results with empirical formula available in literature for the impact analysis.Copyright © 2012 by ASME

Rajesh P. Nair

Papers

Simulation of depth of penetration during ballistic impact on thick targets using a one-dimensional discrete element model

Numerical Simulation of Ballistic Impact on Particulate Composite Target using Discrete Element Method: 1-D and 2-D Models

Soil Structure interaction of Laterally Loaded Piles

Thermal analysis of natural fiber reinforced composites

Simulation of failure of a fixed beam subjected to impact load using quadrilateral discrete element method