Numerical-experimental correlation of rifle firing loads: integrating high-speed dic with explicit dynamics

Abstract

This work proposes and implements a methodological framework for the mechanical characterization of a precision rifle chassis subjected to highly transient loading conditions induced by the firing event. The proposed approach combines high-speed experimental measurements using the Digital Image Correlation (DIC) technique with numerical modeling based on Finite Element Analysis (FEA) in an explicit dynamics framework, aiming at obtaining a consistent experimental–numerical description of the structural response of the system. From an experimental standpoint, the DIC technique enabled the acquisition of full-field displacement and strain measurements under dynamic conditions, providing a robust basis for the identification of structurally critical regions and for the validation of the numerical models. From a computational perspective, an explicit finite element formulation was adopted, which is well suited for representing phenomena characterized by short time scales, high strain rates, and significant inertial effects. The validation strategy, based on the direct comparison between experimental fields obtained via High-speed DIC (HS-DIC) and numerical results, proved to be effective in assessing the adequacy of the modeling assumptions, boundary conditions, and load descriptions. Additionally, this work discusses the importance of constitutive modeling of polymeric materials under dynamic loading, highlighting the limitations of simplified formulations and the need for strain-rate-sensitive models in order to obtain physically consistent predictions. In this context, a strain-rate-dependent constitutive framework is presented, built upon a phenomenological formulation oriented toward computational modeling, with parameters extracted and systematized from data available in the literature, aiming at an adequate representation of the mechanical behavior of the material under high strain-rate regimes.