Characterisation of the impact induced damage in composites by cross-comparison among experimental non-destructive evaluation techniques and numerical simulations

Abstract

Composite fibre-reinforced materials, under low velocity impacts, can experience simultaneous interacting failure phenomena, such as intra-laminar damage, fibre breakage and matrix cracking, and inter-laminar damage such as delaminations. These failure mechanisms are usually the subject of extensive investigations because they can cause a significant reduction in strength of composites structures leading to premature failure. In the present work, composite plates under low velocity impact are investigated. Experimental data, such as experimental curves and images from non-destructive inspections, are used to characterise the low velocity impacts-induced damage in conjunction with a non-linear explicit Finite element numerical model. The adopted numerical model, implemented in the FE code (Abaqus/Explicit) by a user-defined material subroutine (VUMAT), has been demonstrated to be very effective in predicting the damage onset and evolution and, in general, able to correctly integrate the experimental data by providing useful information about the impact damage localisation and evolution.

Acoustic Emission-Based Detection of Impacts on Thermoplastic Aircraft Control Surfaces: A Preliminary Study

“…The occurrence of impacts from random objects, such as ice particles and debris, presents a considerable obstacle in maintaining the structural integrity of composite components for aircraft systems. Conventionally, C-Scan inspections have been utilized for the appraisal of impact-induced damage [1][2][3]. However, this approach is prone to human inaccuracies, is time-consuming, and does not provide real-time results, as assessments can only be conducted between flight operations.…”

Numerical Analysis of the Effect of Microscale Components Interaction on Measurements of Fiber Optic Strain Sensors Used in Composite Structures

“…Existing technologies allow to create highly sensitive, reliable, and miniature sensors that can be embedded in composite structures during or after the manufacturing stage. Up to now, electric, piezoelectric, acoustic, thermal, electromagnetic, and other sensors, fixed at certain points of the analyzed structure, have often been used as sensors of embedded control [4][5][6][7]. Such sensors are used to passively (i.e., without the possibility of influencing the process) monitor disturbances caused by events resulting in occurrence of damage (for example, quick release of acoustic signals or heat), as well as to capture various types of external influence on the structure (for example, vibration, loading, and interactions with the surrounding media).…”

Experimental and numerical analysis of heat convection in cylindrical composite structures with internal defects

“…7 Some relevant information, comparisons, and applications can be found, for example, in literature. 8 –12 Considering composite materials, NDE is applied in the detection of delaminations, impact damage, water entrapment, inclusions, density variations, and evaluation of adhesive bonds. 13 –16 Thermographic NDE (TNDE) systems range from a simple infrared (IR) camera combinations to fully automated inspection systems capable of thickness or defect measurement and advanced materials characterization.…”