Mechanical properties of plain-woven CFRP reinforced by spread fiber tow during and after drop-weight impact

Abstract

For this paper, the impact behaviors and the damage state of plain-woven CFRP reinforced by spread tow due to falling weight were evaluated. Stress-Strain responses of the CFRP using spread tows were investigated under drop-weight impact loading at room temperature. Three leveled impact energy was applied to the surface of the specimen in the drop-weight test. The peak load and absorbed energy were then compared with those of a conventional one and the experimental results showed that the peak load and absorbed energy of the developed CFRP were higher. A large amount of energy was absorbed due to the propagation of macro cracks and delaminations near the counter surface in the developed CFRP. When reinforced by spread tow its structure absorbs a large amount of energy after the initial stage of impact damage. The SAI (static strength after impact) and the FAI (fatigue life after impact) were also examined and the tensile test results showed that the static strength retention of the developed CFRP was higher than those of a conventional one. The developed CFRP also has long fatigue life under the tension-tension cyclic load after the impact. It was found that it maintained superior mechanical properties compared to the original, even after the material was damaged due to impact, because critical propagation of the debonding was prevented around the warp of thin cloth. This paper concludes that reinforcing with spread tow is effective for improving the mechanical properties of plain-woven CFRP during and after impact loading.

Evaluation of the influence of preliminary low-velocity impacts on the residual fatigue life of CFRP composites

“…A hemispherical impactor specified in ASTM D7136 ensures the maximum contact area and internal damage area at a relatively small depth, whilst impacts with sharp prismatic impactors cause deeper damages to the material structure and have relatively small contact areas. The paper Toyota et al (2006) examined different materials and studied static strength after impact (SAI) and fatigue life after impact (FAI), which concluded that reinforcing with spread tow is effective for improving the mechanical properties of plain-woven carbon-fibre reinforced plastic (CFRP) during and after impact loading. The experimental data of residual strength obtained by the methods described above can be used for a design utilising reliability methods (Mohabeddine et al, 2021a, b), residual strength models for cyclic and static loads (Mohabeddine et al, 2021a, b), as well as parameters in analytical models of fracture mechanics (Mohabeddine et al, 2022).…”

Mechanical Properties of Thermoplastic Composites Made of Commingled Carbon Fiber/Nylon Fiber

“…With a higher molding pressure, the flexural properties become slightly better, but these were within the margin of error (Figure 12). There have been few reports about the mechanical properties of composites made from commingled carbon/nylon fiber fabrics, Toyota et al evaluated the mechanical properties of fabrics made from spread commingled carbon fiber yarns coated with nylon resin, and reported that the fabrics made from this had a 20% higher elastic modulus and strength than those made from unspread yarns [27]. The tensile modulus of carbon fiber TR50S12L is 235 GPa, therefore, if the volume fraction is 39 % and the nylon fibers' modulus are ignored, the tensile modulus of composites will be 91.7 GPa if the carbon fibers are aligned in the tensile direction.…”

“…On the other hand, to fully demonstrate the strength of carbon fiber, one study shortened the impregnation distance in the film stacking method by applying “open continuously reinforcing fiber tow,” a technique to thinly and widely spread carbon fiber bundles [ 26 ]. It is also known that the “thin-ply effect” can be obtained, which improves the mechanical properties of the composite materials by reducing the thickness of the prepreg to an extremely low level [ 27 , 28 ]. It is expected that a further fiber-spreading treatment of commingled yarns, consisting of thermoplastic and carbon fibers, could produce superior CFRTP, but few studies have been conducted toward that end.…”

An investigation of Crater Diameter on Plain Slab Foamed Concrete Rice Husk Ash (FCRHA) Exposed to Low Impact Loading

“…The steel blunt nose impactor (see Figure 1c) with 17 kg of weight and 40mm diameter (d) was used through drop weight impact method [14][15][16]. This method was applied where, the impactor dropped at various altitudes of 1.2 m, 1.4 m and 1.6 m which equal to 4.8 m/s, 5.2 m/s and 5.6 m/s respectively.…”