A comprehensive investigation of the low-velocity impact response of enhanced GFRP composites with single and hybrid loading of various types of nanoparticles.

This study investigates the effects of incorporating various types of nanoparticles, both singularly and in hybrid form, on the low-velocity impact (LVI) response of glass fiber reinforced polymer (GFRP) composites. GFRP composites were fabricated using the hand lay-up method and different weight percentages (wt. %) of multi-walled carbon nanotubes (MWCNT), clay, TiO2, and CuO nanoparticles were added into the matrix of composites. To test the LVI response, 14 types of specimens were fabricated with single and hybrid nanoparticle loadings, and LVI tests were conducted using 5 and 10-cm span dimensions at two levels of subjected energy. The experimental results reveal that specimens with a single loading of MWCNT or nano-clay have a lower maximum contact force compared to pure specimens with fully rebounding behavior. This indicates that neither 5 nor 10 cm spans result in severe damages during the impact tests. Furthermore, incorporating more MWCNTs results in stiffer behavior and more brittleness. The study also explores the synergetic effect of adding hybrid nanoparticles in the fabricated composites and discusses the calculated results for absorbed energy. Finally, scanning electron microscopy (SEM) images are analyzed to evaluate the enhancement mechanisms resulting from the addition of nanoparticles to GFRP composite specimens.

A comparative study of 3D printing and heat-compressing methods for manufacturing the thermoplastic composite bone fixation plate: Design, characterization, and in vitro biomechanical experimentation.

Metallic bone fixations, due to their high rigidity, can cause long-term complications. To alleviate metallic biomaterials' drawbacks, in this research new Glass Fiber/Polypropylene (GF/PP) composite internal fixations were developed, and an investigation of their mechanical behavior was performed through in vitro biomechanical experiments. Short randomly oriented, long unidirectional prepreg, and long unidirectional fiber yarn were considered as reinforcements, and the effects on their mechanical properties of different manufacturing processes, that is, 3D printing and heat-compressing, were investigated. The constructed fixation plates were tested in the transversely fractured diaphysis of bovine tibia under axial compression loading. The overall stiffness and the Von Mises strain field of the fixation plates were obtained within stable and unstable fracture conditions. The samples were loaded until failure to determine their failure loads, strains, and mechanisms. Based on the results, the GF/PP composite fixation plates can provide adequate interfragmentary movement to amplify bone ossification, so they can provide proper support for bone healing. Moreover, their potential for stress shielding reduction and their load-bearing capacity suggest their merits in replacing traditional metallic plates.

Biomechanical evaluation of glass fiber/polypropylene composite bone fracture fixation plates: Experimental and numerical analysis.

Little is known about the impact behavior of composite fixation plate used in the fracture healing of long bones diaphysis. Hence, this study examined polypropylene composite fixation plates using different glass fibers and measured their biomechanical responses under axial impact loading experimentally and numerically. Short randomly oriented, long unidirectional prepregs and fiber yarn of glass were considered as reinforcements, and fixation plates were fabricated through two different heat-compressing and 3D printing processes. Furthermore, assessing the fixation plate structures impact behavior was carried out using in vitro impact test and finite element analysis (FEA). Impact damping behavior, damage mechanisms, and stress and strain pattern of the composite fixation plate structures were obtained under various bone fractures and impact energies. The impact load-time responses and the failure mechanisms demonstrated that fixation plate structures with more plastic behavior and lower stiffness could act as an initial shock absorber and dampen the transmission of axial impact load by distributing the impact energy over time. Therefore, considering the ability of stress shielding and adequate interfragmentary movement which amplifies bone ossification, the proposed Glass Fiber/PP (GF/PP) composite fixation plates could serve as a proper alternative in orthopedics.

Enhancement of the Electrical Conductivity and Interlaminar Shear Strength of CNT/GFRP Hierarchical Composite Using an Electrophoretic Deposition Technique.

In this work, an electrophoretic deposition (EPD) technique has been used for deposition of carbon nanotubes (CNTs) on the surface of glass fiber textures (GTs) to increase the volume conductivity and the interlaminar shear strength (ILSS) of CNT/glass fiber-reinforced polymers (GFRPs) composites. Comprehensive experimental studies have been conducted to establish the influence of electric field strength, CNT concentration in EPD suspension, surface quality of GTs, and process duration on the quality of deposited CNT layers. CNT deposition increased remarkably when the surface of glass fibers was treated with coupling agents. Deposition of CNTs was optimized by measuring CNT's deposition mass and process current density diagrams. The effect of optimum field strength on CNT deposition mass is around 8.5 times, and the effect of optimum suspension concentration on deposition rate is around 5.5 times. In the optimum experimental setting, the current density values of EPD were bounded between 0.5 and 1 mA/cm². Based on the cumulative deposition diagram, it was found that the first three minutes of EPD is the effective deposition time. Applying optimized EPD in composite fabrication of treated GTs caused a drastic improvement on the order of 108 times in the volume conductivity of the nanocomposite laminate in comparison with simple GTs specimens. Optimized CNT deposition also enhanced the ILSS of hierarchical nanocomposites by 42%.