<p>Skin can be modeled&nbsp;using a variety of material models to depict its mechanical behavior.&nbsp; Skin shows different behavior like anisotropy, nonlinearity, strain rate dependency, viscoelasticity. Skin is made up of three main layers, namely, Epidermis, Dermis, and Hypodermis. Each layer contains different properties on the microlevel. To reduce the complexity in this paper, we have used whole skin macroscopic models. The macroscopic skin model considers the skin as a single layer and can represent the response of the skin without distinguishing the properties of each layer.&nbsp; Numerous experiments are conducted and presented in the literature for mechanical characterization of skin at the macroscopic level.&nbsp; The primary skin material models are linear elastic, bi-linear elastic, hyperelastic, exponential, and viscoelastic. The best suitable material model among them in case of ballistic or penetrating impact is not studied. &nbsp;The body of a human is almost covered by skin. When a projectile impacted a human body, it has to pass through the skin. It was shown, in previous studies, that the skin plays a significant role in the retardation of the projectile. So, the skin is one of the primary concern targets in ballistic impacts and needs extensive investigation. Furthermore, the injuries created by fragments generated from warheads are the most common cause of injury in recent wars. This makes it essential to simulate the injuries created by fragments in laboratories so that the design of warheads can be improved, producing more effective fragments. There is a requirement of a good skin material model capable of depicting similar responses as natural skin. Thus, the goal of this work is to perform comparative analysis using various available skin material models.</p><p>The sensitivity of choice of the material model on the ballistic response has been studied using nonlinear, transient, dynamic simulations. Towards this end, the data from a projectile-skin impact experiment are used to assess the suitability of a specific material model. The number of ballistic impact simulations are performed using 0.16-, 0.49- and 1.1-gram cylindrical NATO standardized fragment simulating projectile (FSP) using various material models of the skin. The natural fragmentation of warhead is not considered in this paper. Due to the limitation of experimental data in the literature, the controlled parameter analysis in terms of the projectile shape has been done. A dynamic explicit solver LS-Dyna is used to investigate ballistic limit, failure mechanism, and stress-strain responses. Detailed results are presented and discussed in terms of the agreement between simulation and experiments against the aforementioned parameters. This work will be helpful in selecting the skin material model for penetrating ballistic impacts.</p>

Investigation of Skin Material Models for Ballistic Response

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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