As shown in Figure 12, the PPPP-untreated and PPPP-treated laminates exhibited almost the same force–displacement curve. Figure 12, Figure 13 and Figure 14 illustrate the force–displacement and maximum force–displacement curves, respectively, for the laminates with ply orientations of 0°/90°2, ±45°2s. The overall impact strength increased by approximately double that of the PPPP-treated laminate by incorporating the interior carbon ply in the PCCP laminate.
The impact behaviour of hybrid composite plates was examined by Sayer et al. . Hybrid composites are more advanced than conventional fibre-reinforced composites and have more potential for application than other composite materials. There are several different definitions of hybrid composites provided by different researchers.
3. Charpy Impact Response
- This characteristic exhibited by LM1 could be due to brittle fibre breakage and matrix cracking that are less obvious in other laminates (LM2, LM3, LM4 and LM5) with a multidirectional layup sequence.
- Contact force–displacement of the hybrid laminates at ply orientations of 0°/90°2, ±45°2s.
- The results demonstrated that the load-carrying capabilities of hybrid composites are significantly improved than carbon/epoxy laminates, with only a minor compromise in stiffness.
- The crack density depends on the degree of mismatch in the properties between the matrix and the fibre, either due to fibre material or orientation .
- This condition is called resonance and to avoid resonance, the natural frequencies of the structure must be altered by making suitable adjustments in the design.
The absorbed energy of the laminates increased to predetermined impact energy and gradually decreased after reaching the maximum energy value. In general, the low-velocity impact of the laminates demonstrated that the stacking sequence had a significant effect on the impact damage response of the laminate, which is in agreement with previous studies queenwin casino review 28,53,54. In addition, the penetration and perforation occurred at the same impact energy level because of using the carbon ply as the interior layer. All the PPPP-treated laminates exhibited better impact strength compared to PPPP-untreated laminates.
2. Tensile Properties
It was discovered that the stacking pattern influenced the impact performance and stiffness of the laminate. In civil engineering, fibre-reinforced polymer composites (FRPs) are used in reinforcing bars, sandwich panels and structural retrofitting 8,9. Moreover, as a result of material symmetry, the flexural and tensile modulus of symmetric cross-ply laminate improved by 59.5% and 3.97% compared to the unsymmetric counterpart. This includes a unidirectional laminate, cross-ply laminates, and quasi-isotropic laminates.
- The laminates with an exterior carbon layer can withstand high impact energy levels up to 27.5 J.
- However, influencing material behaviour by manufacturing composite laminates with different stacking patterns may be an essential technique for improving the capability to withstand bending force before failure.
- In Figure 6, the PPPP-untreated and PPPP-treated laminates exhibited a similar force–displacement curve trend.
- Therefore, detailed analyses of the low-velocity impact behaviour of PALF/carbon hybrid laminate composites were performed in this study.
- Lee and Kim studied free vibration of a thin-walled laminated composite beam, where a general analytical model applicable to the dynamic behavior of a thin-walled channel section composite is developed.
- The stacking layering sequence in the composite structure is another factor that influences the impact strength in addition to ply orientation.
Table 3.
The flexural test reveals the capability of the composite to resist bending deflection under loading conditions. The laminates were evacuated from the autoclave and then demoulded before cutting them into the required dimensions. As shown in Table 2, five laminates were produced, with each sample containing eight layup plies with a total thickness of 3.50 mm.
Table 1. Material elastic properties
Subsequently, UD prepreg tape was cut into sections of approximately 400 mm by 450 mm before laying up each ply with varying stacking patterns into the mould by hand. The prepreg consists of unidirectional (UD), continuous, high-elongation carbon fibres and an epoxy resin system. Likewise, FRP composites’ brittleness and disastrous failure without sufficient onset warning are generally unacceptable in most engineering applications 12,13,14,15. Fibre-reinforced polymer composites (FRPs) are considered in an application where a high strength-to-weight ratio is desirable. However, because of their superior characteristics, synthetic fibres cannot be completely replaced.
Figure 2
Pure torsional vibrations are focused in this study. The mass is also symmetrical with respect to these axes, and, accordingly, the center of mass coincides with the origin of the y-z coordinate system, so that the flexural-torsional coupling not occurs. The laminated beam is modeled and analyzed by the FEM. Also, composite structural elements consisting of a relatively weak matrix reinforced by stronger inclusions or of different materials in contact are of increasing technological importance in engineering. Qiao Pizhong and Zou Guiping presented an analytical study for dynamic behavior of pultruded fiber-reinforced plastic (FRP) composite cantilever I-beams based on a Vlasov-type linear hypothesis.
The FE analysis by using ANSYS is performed to investigate the influences of boundary conditions on torsional frequencies of the laminated beams. In the present paper, the free torsional vibrations of symmetric laminated beams are studied by the classical lamination theory and shear deformation theory. Glass fiber (E-Glass) is used as reinforcement in the form of unidirectional fibers with epoxy resin as matrix for the laminated composite beams. Also, the effects of boundary conditions on the torsional frequencies of the laminated beams are demonstrated. The effects of fiber direction and laminate stacking sequence on the frequencies of torsional vibrations were investigated.
PCCP and CPPC laminates absorbed energy well at low impact; however, they degraded significantly at high impact energies. The situation is visible at the maximum impact energy for both laminates, with the PCCP absorbing nearly all of the energy and the CPPC absorbing just approximately 80%. This explains why the elastic potential energy of the laminates is transformed into impactor kinetic energy, decreasing the absorbed energy .