Fatigue Behavior of Al 7075-T6 Plates Repaired with Composite Patch under the Effect of Overload

Repair of aeronautical structures by composite patch bonding has shown its effectiveness in several studies during the last few decades. This repair technique leads to a retardation in the propagation of repaired cracks via load bridging across the patch throughout the adhesive layer, interfacing it with the repaired structure. The purpose of this study is to analyze the behavior of patch-repaired cracks present in thin plates made of aluminum alloy 7075-T6 and subjected to a single tensile overload. The sequence of application of overload on the fatigue behavior was also studied. Fatigue tests were conducted on Al 7075-T6 notched specimens where crack growth and number of cycles to failure were monitored for different patching/overload scenarios. A detailed fractographic study was performed on failed specimens to analyze the micromechanical behavior of the crack growth related to each scenario. The obtained results showed that the application of the overload before bonding the patch leads to an almost infinite fatigue life of the repaired plates

Fatigue Behavior of Al 7075-T6 Plates Repaired with Composite Patch under the Effect of Overload

Repair of aeronautical structures by composite patch bonding has shown its effectiveness in several studies during the last few decades. This repair technique leads to a retardation in the propagation of repaired cracks via load bridging across the patch throughout the adhesive layer, interfacing it with the repaired structure. The purpose of this study is to analyze the behavior of patch-repaired cracks present in thin plates made of aluminum alloy 7075-T6 and subjected to a single tensile overload. The sequence of application of overload on the fatigue behavior was also studied. Fatigue tests were conducted on Al 7075-T6 notched specimens where crack growth and number of cycles to failure were monitored for different patching/overload scenarios. A detailed fractographic study was performed on failed specimens to analyze the micromechanical behavior of the crack growth related to each scenario. The obtained results showed that the application of the overload before bonding the patch leads to an almost infinite fatigue life of the repaired plates

Potential of recycled polypropylene: A study on effect of natural fiber on the morphology and properties of biocomposite

This research explores the innovative fabrication and characterization of recycled polypropylene composites that reinforced by natural fibers, specifically date palm micro fibers (DPF). Employed a twin-screw extruder for the mixing, and injection molding technique for the samples fabrication. DPF was incorporated at varying weight percentages (0, 2, 5, and 10 wt%). A comprehensive analysis, including thermal gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), was conducted to assess thermal stability, chemical interactions and crystalline structure. Mechanical properties were evaluated through shore-D hardness and uniaxial tensile tests. Notably, the study revealed that an increased DPF filler content resulted in superior mechanical properties, such as enhanced shore-D hardness and tensile strength. This improvement was attributed to the alignment of DPF fillers and the recycled polypropylene matrix. The significance of this research lies in showcasing the promising potential of DPF as an eco-friendly reinforcement material in recycled polypropylene biocomposites, providing a sustainable and environmentally friendly alternative for various engineering applications. The work contributes to advancing greener solutions in material science and highlights the unique advantages of DPF in enhancing composite materials