Krzysztof Majerski

The impact behavior of aluminum hybrid laminates

Purpose – The purpose of this study was to carry out the analysis of impact resistance for aluminum hybrid laminates and polymer matrix composites reinforced with glass and carbon fibers. Damage modes and damages process under varied impact energies are also presented and discussed. Design/methodology/approach – The subject of examination were fiber metal laminates – FMLs (Al/CFRP and Al/GFRP). The samples were subjected to low-velocity impact by using a drop-weight impact tester. The specimens after impact were examined using non-destructive and destructive inspection techniques. Findings – The hybrid laminates are characterized by higher resistance to impact in comparison to the conventional laminates. The delaminations between composite layers as well as the delaminations on metal/composite interface and lateral cracks are the prevailing type of destruction mechanisms. No significant relationships between metal volume friction coefficient vs response to the impact were recorded for the hybrid laminates...

Experimental investigation on the influence of fibers orientation on the failure of carbon hybrid laminates

Purpose – The purpose of this paper is to present microstructural and fractographic analysis of damage in aluminum (2024T3)/carbon-fiber reinforced laminates (AlC) after static tensile test. The influence of fiber orientation on the failure was studied and discussed. Design/methodology/approach – The subject of examination was AlC. The fiber–metal laminates (FMLs) were manufactured by stacking alternating layers of 2024-T3 aluminum alloy (0.3 mm per sheets) and carbon/epoxy composites made of unidirectional prepreg tape HexPly system (Hexcel, USA) in [0], [± 45] and [0/90]S configuration. The fractographic analysis was carried out after static tensile test on the damage area of the specimens. The mechanical tests have been performed in accordance to ASTM D3039. The microstructural and fractographic analysis of FMLs were studied using optical (Nikon SMZ1500, Japan) and scanning electron microscope (Zeiss Ultra Plus, Germany). Findings – FMLs based on aluminum and carbon/epoxy composite are characterized by...

Investigation of the Effect of Forging Temperature on the Microstructure of Grade 5 Titanium ELI

The paper reports the experimental results of an investigation of the effect of forging temperature on the microstructure and hardness of Grade 5 titanium ELI. A growing interest in the use of titanium alloys in implantology results from their unique properties. Grade 5 titanium ELI is widely used in medicine for producing a variety of implants and medical tools such as hip, knee and shoulder joints; bone plates; pacemaker casing and its components; screws; nails; dental materials and tools. In the first part of the paper the properties of Grade 5 titanium ELI are described and examples of medical applications of this alloy are given. In a subsequent section of the paper, forging tests performed on this biomaterial in a temperature range from 750°C to 1100°C are described. Following the forging process, the results of the titanium alloy’s microstructure and hardness are reported. The experimental results are used to determine the most suitable forging temperature range for Grade 5 titanium ELI with respect to its microstructure.

Forming of thin-walled profiles made of FML in autoclave process

Purpose The purpose of the study was to develop the forming methodology for FML laminates with complex shapes, based on aluminium and epoxy – glass composite. Design/methodology/approach The subject of research encompassed Al/GFRP fibre metal laminates. Autoclave process has been selected for FML profiles production. Manufacturing process was followed by quality analysis for laminates produced. Findings The achievement of high stability and dimensional tolerance of thin - walled FML laminates is ensured by developed technology. The values of selected sections angles are significantly limited as a result of forming of FML laminates through the components performing. Failure to adhere to technological recommendations and to high regime of developer technology may lead to the occurrence of defects in FML. Practical implications Thin-walled composite structures could be applied in light weight constructions, such as aircraft structures, which must meet rigorous requirements with regard to operation under comp...

Study of low-cycle fatigue of glass-hybrid laminates

Purpose The purpose of the article is to present the results of research in the scope of fibre metal laminates reinforced with glass fibres in low-cycle fatigue conditions in the range of limited number of cycles. Design/methodology/approach The tests have been carried out on open hole rectangular specimens loaded in tension-tension at high load range of 80 and 85% of maximum force determined in static test, correspondingly. The number of cycles for destruction has been determined experimentally. Findings By means of microscopic observations, it was possible to determine the moment of cracks initiation and their growth rate. Furthermore, it was possible to identify the impact of reinforcing fibres orientation in composite layer, material creating the metal layers, on fatigue life and on nature of cracks propagation. Practical implications This work validates the possibility of increasing the resistance of metal-fiber laminates for low-cycle fatigue by modifying the structure of the laminate. Originality/v...