Mechanical performance and damage mechanisms of thin rectangular carbon/ Elium® tubular thermoplastic composites under flexure and low-velocity impact

This work investigates the effects of interlayer hybrid fiber dispersion on the impact response of carbon-flax epoxy hybrid laminates at low carbon volume fractions, and benchmarks the mechanical performance enhancement against the non-hybrid flax epoxy. Five hybrid laminate stacking sequences with similar carbon-to-flax weight ratio were fabricated and subjected to low-velocity impact at three different energy values, generating non-perforated and perforated damage states. A virtual drop-weight impact test that models intralaminar failure based on continuum damage mechanics approach, and delamination using cohesive elements, was also implemented to evaluate the material behavior and damage development in the composites. Simulation results were then verified against experimental data. Results suggested that positioning stiffer carbon plies at the impact face does not necessarily lead to enhancement of the hybrid's impact properties. On the contrary, flax plies at the impacted side lead to significant improvement in impact resistance compared to the non-hybrid flax composite with similar thickness. Results of finite element analysis showed that carbon plies play a significant role in the hybrid laminate's energy absorption characteristics due to lower failure strain.

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NUMERICAL MODEL OF TUBULAR COMPOSITE SANDWICH STRUCTURES UNDER LOW-VELOCITY IMPACT

10.12783/asc36/35809 ◽

2021 ◽

Author(s):

CHAO ZHANG ◽

ISAIAH KAISER ◽

K. T. TAN

Keyword(s):

Sandwich Structures ◽

Matrix Cracking ◽

Impact Response ◽

Low Velocity Impact ◽

Core Material ◽

Low Velocity ◽

Damage Mechanisms ◽

Velocity Impact ◽

Composite Sandwich ◽

Composite Sandwich Structures

This study aims to investigate the dynamic impact response of tubular composite structures with honeycomb sandwich core under transverse low-velocity impact (LVI) test. We establish a finite element analysis (FEA) model of composite sandwich structures. Simulation results are compared with experimental results to verify the correctness of the model and analysis method. This model can accurately predict the impact response and damage mechanisms of a composite sandwich structure, as validated by experimental testing, specifically capturing major failure modes. LVI experiments are conducted utilizing cylindrical impact striker to enact both point and line impact. Damage mechanisms, such as matrix cracking, delamination, and fiber breakage/rupture, occur in the facesheet, as well as honeycomb crushing and breakage in the core. The combination of experimental and numerical results illustrates the effects of facesheet thickness and core thickness on failure mechanisms. A three-dimensional model can also be used to clearly visualize the effect of different core material properties on the failure mechanism and dynamic response during an impact event.

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