Energy Absorption Capability Of Composites Research Articles

Interphase enhanced low-velocity impact energy absorption in liquid crystal elastomer-based woven composites

A reasonable approach to enhancing the energy absorption capability of composites is to incorporate elastomers that possess viscoelastic properties capable of enduring considerable elastic deformations and absorbing significant energy without fracturing. From this perspective, using liquid crystal elastomers (LCEs) as a matrix for fiber-reinforced composites could be an excellent option for developing impact-absorbing materials since LCEs possess an outstanding energy dissipation ability compared with amorphous elastomers. Herein, we report excellent energy-dependent impact properties of LCE composites reinforced with carbon fiber (CF) woven fabric. We discovered that the LCE/CF composite can effectively dissipate high amounts of low-velocity impact energy. The exceptional characteristics of LCE, which make it adaptable to impact energy absorption, combined with the presence of an interphase featuring a higher loss modulus compared to the individual composite components, were demonstrated to significantly enhance impact energy absorption of the composite. The developed LCE/CF composite panel is capable of absorbing up to 60 J of impact energy despite its thickness of only about 1 mm and has a substantial damping loss coefficient of about 0.1, which is two orders of magnitude higher than those of typical fiber-reinforced composites.

Tailorable rigidity and energy-absorption capability of 3D printed continuous carbon fiber reinforced polyamide composites

The aim of the present work was to study the tailorable rigidity and energy absorption capability of 3D printed short and continuous carbon fiber reinforced polyamide (3DP-scCFRPA). The synergistic reinforcement of laminates by both short and continuous carbon fibers was superior to the individual carbon fiber reinforcement for the mechanical properties. Continuous carbon fiber raster angle, stacking sequence and loading direction were considered as the main factors affecting mechanical properties of 3DP-scCFRPA in this investigation. The flexural strength, modulus and energy absorption capability of 3DP-scCFRPA were investigated by three-point bending testing. The deformation processes and failure mechanisms of laminated composites were analyzed in association with morphological evolution. The results showed that laminates with 0°continuous fiber raster angle (along with the length direction), separated distribution of continuous carbon fiber layers, and loaded in thickness direction, presented the highest flexural modulus and strength as high as 16.1 GPa and 262.0 MPa, respectively. The printed laminates with ± 45° continuous fiber raster angle, separated distribution of continuous carbon fiber reinforced layers, and loaded in width direction showed the highest energy absorption of 1613.3 MJ/mm3. Continuous fibers with 0° raster angle could effectively improve rigidity of composites. The introduction of ±45° layers into laminates significantly increased the energy absorption capability of composites. Separated continuous fiber reinforced layers were helpful to impede crack propagation and presented better interfaces with higher interfacial strength between 3D printed layers.

Investigation into energy absorption capacity of composites reinforced by three-dimensional-weft knitted fabrics

Energy absorption capacity is of great importance in engineering applications such as bumpers, helmets and packaging. Textile-made composites have attracted world's attention due to their high energy absorption and lightweight. This study aims at evaluating energy absorption capability of composites reinforced by three-dimensional-weft knitted fabrics. To achieve this purpose, weft knitted fabrics with different structures and surface densities were prepared from nylon yarns. Having washed the fabrics, their shapes have changed to three-dimensional ones using a thermoforming process and specific casting. Three-dimensional fabrics were first covered by epoxy resin and then laid in a bed of poly vinyl chloride foam in order to improve their energy absorption capacities. Quasi-static pressure and dynamic pendulum impact tests were carried out for samples. The results were analyzed by the Minitab software and optimal sample was determined.