Identification and modelling of the ballistic performance of advanced Ceramic ArmouR – ICAR

In the framework of the previous Astrid Mhica project (2019-2023) two types of original dynamic experiments were developed: on the one hand ballistic impact tests of API-BZ projectile cores on ceramic/composite bi-layer targets were conducted in a sarcophagus configuration. These tests led to an analysis by microtomography of the damage and multiple-cracking modes in the ceramic, in the composite (delamination) but also in the projectile core (fragmentation). On the other hand, quasi-oedometric compression tests (compression with a confinement ring) were carried out on samples of ceramics pre-fragmented by impact. However, due to the loading path adopted (uniaxial strain) these tests showed a linear behavior, which did not make it possible to identify the failure envelope of the fragmented media. On the other hand, numerical simulation work was carried out using the Abaqus FE code and the JH2 model (Johnson-Holmquist). But this work has come up against serious shortcomings concerning the behavior under confinement of virgin and pre-damaged ceramics.

The ICAR project aims to fill these experimental and numerical gaps. On the experimental level, it is a question of developing a triaxial cell making it possible to carry out triaxial tests on ceramic with virgin or pre-fragmented samples operating at pressures which can exceed 1 GPa. These tests applied to 5 commercial armor ceramics will make it possible to constitute a database supplemented by the work in progress in the thesis of J. Genevois (2020-2023) related to the characterization of ceramics under plate impact tests. This database will allow finalizing the identification of a JH2-DFH plasticity-damage model for each microstructure. This numerical model will be validated by numerical simulation of laboratory impact tests (experimental configuration of the Mhica project). Finally, the numerical tool will be used to conduct a parametric study to compare the performance of armor ceramics in different integration configurations (choice of different ammunition cores and backings). Thus, the project will lead to a better understanding of the influence of the mechanical behavior of armor ceramics under high confinement on their ballistic performance.