Resumo:
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.
