Physically-sound simulation of low-velocity impact on fiber reinforced laminates

• Mesoscale simulation of low-velocity impact (LVI) on composite laminates by means of Continuum Damage Models and Cohesive Models implemented in Finite Element software package Abaqus.
• Implementation of user subroutines for damage models.
• Exploration of different numerical techniques for the correct simulation of LVI on composite laminates at constitutive and kinematic level, as for instance cohesive contacting surfaces and mesh alignment with orthotropic material directions.
• Comparison with experimental results and reference to state-of-the-art work in the literature.
• Remarkable results are obtained at several impact energies. With the use of general-application modeling techniques, the simulations are able to capture delamination, matrix cracks, fiber splitting, permanent specimen indentation and perforation. This represents a remarkable improvement with what is reported in the available literature, and to the author's beliefs, will represent a breakthrough in the way laminated composites are modeled when under impact loading.

A high-fidelity virtual tool for the numerical simulation of low-velocity impact damage in unidirectional composite laminates is proposed. A continuum material model for the simulation of intraply damage phenomena is implemented in a numerical scheme as a user subroutine of the commercially available Abaqus finite element package. Delaminations are simulated using of cohesive surfaces. The use of structured meshes, aligned with fiber directions allows the physically-sound simulation of matrix cracks parallel to fiber directions, and their interaction with the development of delaminations. The implementation of element erosion criteria and the application of intraply and interlaminar friction allow for the simulation of fiber splits and their entanglement, which in turn results in permanent indentation in the impacted laminate. It is shown that this simulation strategy gives sound results for impact energies bellow and above the Barely Visible Impact Damage threshold, up to laminate perforation conditions.