Volume 66, Issue 2

Data streams in science and economy are becoming increasingly automatized. This has various advantages compared to previous, user-dependent analyses, in which the same results are analyzed differently by different persons. Even though these differences are only of a certain degree, they can lead to false estimations of underlying material and process parameters as well as to missing comparability. In order to automatize previously user-dependent processes in the analysis of material tests, a modular database management system, called idCarl, has been developed. This system places a module as  analysis pipeline between the experimental machine and the database. The database management system can be expanded with diverse modules, enabling the generation of user-independent data, which are fed automatically into the database. To provide an example, a module is applied to the common procedure of tensile testing based on DIN EN ISO 6892 and CWA 15261-2. The module determines automatically Young’s modulus and other parameters derived thereof. The method for determining the measurement uncertainties of the Young’s modulus is improved and compatibility with the “Guide to the expression of uncertainty in measurement” (GUM) is achieved. The existing method in ISO and CWA standards provides in some cases an underestimation of about 112 %.

Sandwich panels are used as body components of vehicles in many sectors, such as defense, aircraft, and aviation, due to their advanced mechanical properties and lightness. This study aims to investigate the effect of core configurations on mechanical performance and deformation behavior of metallic sandwich panels under low-velocity impact loading. For this purpose, metallic sandwich panels having monolithic and sliced core configurations were first produced. Low-velocity impact tests were carried out using varying energy levels (20, 40, 60 J) to examine how the intensity of influence affects the deformation of the sandwich panel. The perforation and deformation behavior on the upper surface plates of sandwich panels were evaluated. Experimental results showed that the core design significantly affects the impact behavior of sandwich panel samples. The sliced core configuration produced approximately 10 % more maximum contact force and absorbed 14 % more impact energy at high-impact energy levels. Additionally, the sliced core configuration delayed core collapse of the core in deformation situations where complete perforation does not occur.

The total heat input by the laser directly affects the temperature distribution of the rotor shaft during the cladding process, and then affects its coaxiality. This article uses ANSYS for numerical simulation to study the effect of laser heat input on the deformation of the rotor shaft during laser cladding process. Simulate and analyze the temperature and stress fields inside the rotor shaft using thermal coupling. The results show that by changing the pitch, axial cladding width and laser irradiation duration to change the laser induced total heat input, a more uniform temperature distribution can be generated in the rotor shaft. The increase of temperature distribution uniformity can reduce the deformation of rotor shaft during cladding. Using a cladding equipment, iron based customized alloy powder was coated on the 45 steel rotor shaft for cladding experiments. And the mechanical properties and coaxiality of the rotor shaft after cladding were measured. The results showed that the hardness and wear resistance of the cladding layer were significantly improved compared to the substrate, and the changes in coaxiality of the rotor shaft were consistent with the simulation results, with relatively small errors. It is of great significance for repairing damaged rotor shafts.

Hexaaluminates are drawing attention due to their exceptional mechanical and thermal stability. They can be proposed for applications as catalysts or catalyst support materials in high-temperature reactions. In this study, various LaFe x Al 12− x O 19 samples ( x  = 0.25, 0.5, 1, and 2) have been synthesized using the sol–gel method. Subsequently, these hexaaluminate samples were impregnated with cobalt oxide to form more active centers on the hexaaluminate support. The influence of the iron (Fe) content on the crystal structure, redox properties, and oxygen immobility has been investigated through X-ray diffraction, hydrogen temperature-programmed reduction, and oxygen temperature-programmed desorption techniques. Among the Co 3 O 4 @LaFe x Al 12− x O 19 samples, those with x  ≥ 1 exhibited a hexaaluminate crystalline structure, demonstrating a higher lattice oxygen mobility.

This study experimentally investigated the energy-absorbing capability of foam-filled 6063-T5 aluminum tubes. Thus, different sample combinations were created with two different foams, PVC (80 kg m −3 ) and aluminum (200, 350 kg m −3 ), which were used as filling materials. The first group of samples consisted of uniform foam-filled aluminum tubes. In contrast, tubes were filled with radially graded foams in the second group, which included a ring PVC foam and a cylindrical aluminum foam in the center. Empty tube absorbed 329 J, while it reached the values of 384, 488, and 606 J by using PVC and low- and high-density aluminum foams, respectively. The specific energy absorption value of the empty tube was obtained as 23.2 J g −1 . In comparison, it was 19.3 J g −1 in the high-density aluminum foam-filled sample, although it absorbed the highest energy value. This shows that high-density aluminum foam was inefficient in terms of the crashworthiness of the structure. Finally, the best sample regarding the specific energy absorption and crush force efficiency was obtained in the sample where the PVC foam ring and high-density aluminum tube were used together. This sample had 7 % higher specific energy absorption and 34 % higher crush force efficiency than the empty tube.

One of the most researched technologies among technologies used for producing complex and diverse parts today is additive manufacturing. In additive manufacturing, production can be carried out using thermoplastic and metal materials without requiring an additional process. Among the additive manufacturing technologies, the Fused Filament Fabrication (FFF) method is the most widely used method worldwide due to its affordability and broad application area. FFF is a method in which part formation is achieved by depositing melted materials on each other. In recent years, polymer materials such as polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and acrylonitrile butadiene styrene (ABS) have been frequently used in many industrial areas in the FFF method because they are lightweight, inexpensive, sustainable, and provide sufficient strength for engineering applications. This study conducted tensile, three-point bending, Charpy, and compression tests on PLA, PETG, and ABS materials at angles of 15°–75° and 30°–60°, and the results were compared.

Si 3 N 4 and Invar alloy brazed joints were achieved using two types of Ag-based interlayers: a Ag–Cu–In–Ti foil and a Ag–Cu–In–Ti/Cu/Ag–Cu multi-interlayer. The results showed that when only using a single Ag–Cu–In–Ti filler, the wave-shaped Fe 2 Ti + Ni 3 Ti intermetallic compounds are concentrated in the middle of the brazing seam. When adding Cu as the interlayer, the dissolution of the Cu interlayer formed a large number of Cu(s,s) blocks of different sizes in the brazing seam, which hindered the concentrated distribution of Fe 2 Ti + Ni 3 Ti intermetallic compounds in the brazing seam. As a result, Fe 2 Ti and Ni 3 Ti were dispersedly distributed in the brazing seam, increasing the shear strength of the brazed joint. The shear strength of brazed joints was increased by 82 % compared to joints brazed with a single Ag–Cu–In–Ti filler when the Cu interlayer was added.

In recent years, alternative approaches have been implemented in the automotive sector to reduce raw material costs and protect the environment. An increase in weight causes both fuel consumption and CO 2 emissions to rise. This study aims to reduce exhaust emissions due to weight reduction by using foamed polypropylene in the door panel production of a subcompact crossover SUV car and saving energy by shortening the injection cycle time. The newly produced 2 % ITP 822 chemical foaming agent added door panel was compared with the current door panel performances. As a result of foam morphology structure, impact, and hardness tests, it was decided that ITP 822 is a suitable chemical foaming agent. In addition, a weight reduction of 5.2 % was achieved. Moreover, the injection cycle time has been reduced by approximately 12 %, reducing the total cycle time from 35 s to 31 s.

The effects of zinc, steel, aluminum, and brass materials that can be used instead of copper in brake friction composites on braking performance were investigated in this study. The specimens containing three different ratios of metallic shavings were produced by the dry mixing method. In terms of comparison, a total of 16 specimens were examined by producing the specimen containing copper at the same rates and the specimen containing no metallic chip. The weight loss, specific wear rate, and friction coefficient of the specimens were determined by the brake test results. The hardness and density tests were carried out. Thermal conductivity tests of the specimens were carried out to determine the thermal characteristic of copper. Among the metallic chips used, aluminum and steel wool were found to be good alternatives to copper.

This study aimed to produce hybrid composites with a AA2024 matrix reinforced by TiC/B 4 C/nano-graphite through a microwave-assisted sintering technique at 560 °C for 60 min. The nano-graphite ratio in the produced composite samples was kept constant as 1 wt.%. TiC and B 4 C were used in equal ratios at 2, 6 and 10 % by weight total to determine their effects on tribological properties. Wear tests were conducted under three different loads: 3, 5 and 10 N. In the hybrid composites produced, an inverse correlation was observed between the increase in reinforcement ratio and sinterability, while a direct correlation relationship was found in hardness and wear resistance. Compared to the sample containing 2 % TiC/B 4 C in total by weight, a ∼50 % increase in Brinell hardness and a 52–68 % decrease in wear rate was obtained in the sample containing 10 % TiC/B 4 C. As the reinforcement ratio increased, tribofilm formation increased, and abrasive wear was replaced by mild-oxidative wear type.

AA6082-T6 aluminum alloy is used in different engineering applications. The erosive wear takes places in many machine parts. The prediction of wear amounts for aluminum alloy materials is complicated and nonlinear phenomena. The fuzzy inference systems (FIS) and the artificial neural networks (ANNs) have a series of properties on modeling nonlinear systems. In this study, it was aimed to determine the optimum erosive wear parameters in terms of wear resistance. This study suggests a meta-heuristic (sine–cosine algorithm-SCA) Based ANFIS prediction model for prediction of wear behavior of AA6082-T6 aluminum alloy within various impingement pressure, impact velocity, impingement angle and particle sizes. In this study, a model is developed that determines the optimum erosive wear parameters to achieve the minimum wear rate. The erosion rate-SCA Based ANFIS prediction model extracted reasonable results. Estimation capability has been achieved to 99.81 % by the proposed model.

Safety in elevators is extremely important phenomenon. Elevator accidents occurring today are at a level that seriously threatens the safety of life and property, and especially elevator ropes and belts have a very important place in these systems in order not to endanger human life. As with every mechanism, stress, fatigue and deformations occur in elevator parts and equipments such as ropes and belts over time causing impairment and reduce their strength. In this study, artificial defects were given to the 8 × 19 Warrington steel wire rope and polyurethane coated elevator belt to examine the effects of different type of corrosion and elevated temperature deterioration on mechanical properties and their comparisons were made. Results indicate that the percent reduction in lifting capacity of the elevator belt investigated was lower than that of the 8 × 19 Warrington rope in all degradation types examined.

Friction stir-based variants have entirely changed the outdated component manufacturing method. Magnanimously, it has reached notable achievement in the joining, fabricating and processing of aluminum materials. This research article aims to review the various classifications of friction stir-based techniques. Friction stir-based techniques have improved the joining method along with microstructure and mechanical properties of the material. This article will enlighten the recent progress on friction stir additive manufacturing techniques applied on alloys or fabrication of composites, friction stir welding, additive friction stir deposition, friction stir processing and friction stir cladding. Mechanical properties, feasibility, applications, limitations and process parameters are discussed in details. This review article will help industry persons and academicians to know the process parameters of various techniques along with the outcomes and changes in mechanical and microstructural properties. In the last, challenges in variants of friction stir-based processes were also mentioned.

Cryogenic cooling and minimum quantity lubrication (MQL) are regarded as effective green manufacturing techniques since they eliminate the excessive utilization of conventional cutting fluids (CCFs) that are known to have adverse impacts on both the environment and human health. Moreover, these methods have promising effects on surface integrity in machining hard-to-cut materials. This study investigates the impact of hybrid and cryogenic lubri-cooling methods on surface integrity (surface roughness, microhardness, and residual stresses) in hard turning of AISI 52100 bearing steel (62 HRC) with conventional and wiper CBN inserts. For that purpose, a precooling-based hybrid (a combination of precryogenic cooling of the workpiece and MQL) and direct cryogenic cooling techniques were used for comparison during the hard turning tests. The tests were carried out at a constant cutting speed (200 m/min), feed (0.1 mm∙rev −1 ), and depth of cut (0.1 mm) under dry, carbon dioxide (CO 2 ), liquid nitrogen (LN 2 ), CO 2 + MQL, and LN 2 + MQL conditions. The results show that hybrid lubri-cooling condition (CO 2 + MQL) improved the surface quality and increased the compressive residual stresses at the machined surface when wiper inserts were employed. On the other hand, effective cooling under direct CO 2 condition provided better surface integrity when machining with conventional inserts.