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Nowadays, the increasing use of plastic materials in friction and wear applications, particularly in industrial robotic grippers, is a growing trend in modern industry. Plastics are replacing traditional materials like metals and composites due to their unique properties and significant advantages. Plastic materials used in industrial robotic grippers offer several advantages, such as their low friction coefficient, enabling smooth and precise movement of the gripper and minimizing the risk of damaging the objects being manipulated. This paper presents a comparative study and analysis of the friction coefficient between various plastic materials and the C45 alloy steel, a superior alloy used in industrial applications. The investigated materials include PETG, PLA, PLA with aluminum, ABS, two types of TPU, and two types of UV-sensitive resins. This study aims to evaluate the friction performance of these materials in order to identify the most suitable options for friction and wear applications, such as industrial robotic grippers. To achieve this, dry kinetic friction tests were conducted between 3D printed plastic material samples manufactured by using FDM and SLA technologies, and the C45 alloy steel on the CETR UMT-2 tribometer. The friction coefficient was measured by recording the force required for displacement in two horizontal directions.

The plastic speed meter housing for automobiles requires accurate parts and assembly to inform the driver of their exact speed. For accurate assembly, the molded speed meter should have a minimize amount of deformation. In this study, to obtain injection molding conditions that minimize the deformation of the speed meter, the main molding conditions that cause the deformation of the speed meter were identified using the Taguchi method. By combining the confirmed molding conditions, 150 data sets were created, and machine learning was conducted using the data set. The model with the best accuracy learned through machine learning was the Linear Regression model. The results of this Linear Regression model were then validated with test data. The optimal injection molding conditions were derived by inputting 5000 molding conditions data into the learned Linear Regression model. Injection molding analysis was performed using the derived injection molding conditions, and the amount of deformation was reduced by about 6.4% compared to the case where current molding conditions were applied. The optimal molding conditions obtained by machine learning were applied to actcual molding. The amount of deformation of the mold amount of the molded speed meter housing was smaller than the amount of deformation predicted in the machine learning model.

This study has proved the value of the bioplastics in replacing the classical polymers used for various applications by employing a new and original econometric model which underlines the interdependence between the bioplastics price and the following mechanical properties: Young modulus, Tensile strength and Elongation at break. The model was applied for 5 different bioplastics: polylactic acid (PLA), cellulose acetate (CA), poly (butylene succinate) (PBS), Bio-polyethylene (Bio-PE) and Bio-polyethylene terephthalate (Bio-PET). The biopolymers cover a large range of bioplastics both biodegradable and non-biodegradable. The developed model was run on Gretl software using the OLS (ordinary least squares) method. The residuals values are acceptable which means that the interdependence model fitted well the known data. Among all bioplastics studied, polylactic acid (PLA) exhibits the best constants in terms of reproducibility. All the regression equations obtained for the econometric study offer the possibility of forecasting the price for any other sort of bioplastic and it is a useful tool for assessment the financial impact of a bioplastic.

The paper proposes the analysis of strain and stress state, through experimental and numerical means, of a circular hole type concentrator. The strain state is analyzed through the microscopic Digital Image Correlation technique, due to the small scale of the samples, whose calibrated region is 10x8 mm. The numerical analysis is conducted using the Finite Element Method, through a static structural analysis, using a linear-elastic material model. The results from the two procedures are compared by means of strain field distribution around the stress concentrator and stress variation at the concentrator peak cross section. For validation, the analytical gross stress concentrator of the problem is used as baseline, Ktg. The results show that accurate reading can be achieved on this small scale. Additionally, the experimental method has also successfully identified crack initiations and propagations on the tested samples, significantly smaller than 1 mm, which can reveal future fracture mechanics analysis and supply data to models adapted to microscopic scale phenomena.

The main objective of the research was to study the influence of the abrasive water jet cutting (AWJC) parameters on the surface roughness parameters Rz1max and Rt, obtained when processing Kevlar fiber-reinforced polymers (KFRP). For this purpose, a full factorial experimental program was designed and roughness evaluations were carried out in two different zones of the cut slot. In this way, it was possible to test the statistical significance of the input parameters effects and characterize both these regions, by means of prediction models proposed for each roughness parameter. Finally, response surfaces and level curves were represented to facilitate the selection of proper factors combination to achieve surface finish requirements.

A study was conducted on SEBS-based composites granules containing different volume fractions of carbon nanotubes (CNTs) using a twin extruder and hot pressing procedure to produce a SEBS/CNTs membrane. SEM was used to study the membrane`s morphology, revealing a 3-D network of CNTs. TGA was utilized to measure the degradation temperature of SEBS polymer and determine the actual volume fraction of CNTs. The mechanical properties, electrical conductivity, and cyclic strain sensing behavior of the SEBS/CNTs were investigated using a tensile testing machine and pico-ammeter. Mathematical models were used to fit the measured data, demonstrating the strain sensing potential of the composites. The composite membrane with 2 wt.% of CNTs exhibited superior electromagnetic wave absorption performance with a minimum reflection loss (RLmin) value. This study provides promising opportunities for the development of advanced materials.

Using the experimental determinations obtained on the basis of compressive stress, some mechanical properties were studied for composite materials with the matrix of three types of resin, epoxy, unsaturated polyester and hybrid based on Dammar natural resin, which was reinforced with isophthalic resin granules NPG (Neopentyl Glycol) Chromat Kayan / Javari / Payette type. The stress-strain diagrams, compressive yield strength, compressive strength and modulus of elasticity in uniaxial compression were obtained. With the EDS analysis, the graphical distribution of the atomic spectra of the elements identified in the hybrid resin was determined and the image of the fracture surface of a hybrid resin specimen was presented based on the stereomicroscopic analysis (SEM).

Acoustic protection is an important aspect in various industrial, commercial and residential applications. In order to reduce the transmission of noise, perforated panels are frequently used as a barrier. The present study aims to conduct a numerical analysis of plastic perforated panels for acoustic protection. The study employed a finite element method (FEM) approach and focused on the propagation of acoustic waves through perforations of varying diameters (30 mm, 40 mm, 50 mm, 60 mm, 70 mm and 90 mm) and at different frequencies (250 Hz, 500 Hz, 1000 Hz and 1500 Hz). The numerical analysis was conducted using the finite element software ANSYS. This work offers numerical analysis models of acoustic wave propagation, which can be used by those interested in similar problems, for different environments, in closed or open spaces. The results showed that the perforation diameter and frequency play a crucial role in the performance of the plastic perforated panels as an acoustic barrier. The results of the author’s research pointed out that the plastic materials can be used successfully in the construction of acoustic barriers. Next to it, the findings of this study can provide valuable insights for engineers and designers in the selection and optimization of plastic perforated panels for acoustic protection applications.

To attain good geometric shape and size, machining of high-strength metal Fiber laminate becomes inevitable in the field of automotive industries. In this research, aluminum foam sandwiched with glass fiber reinforced polymer (GFRP) composites fabricated using a hand layup process. The glass Fiber composite was fabricated using aluminum foam with a thickness of 1 mm. The effect of abrasive water jet parameters such as pressure (P), stand-off distance (L), and nozzle diameter (D) on material removal rate (MRR) and Kerf angle (Ka) and Surface roughness were investigated. The results were compared without aluminum foam composites. Glass fiber composites with aluminum foam reduced the kerf angle by 44.18 %, and surface roughness (Ra) by 41.77 % as compared with glass fiber composites without aluminum foam. From the investigation, it was noticed that maximum pressure (220 Bar) and minimum stand-off distance (1mm) were optimum parameters for reducing the kerf angle and surface roughness. Also, Optical images of the hole were analyzed for surface quality.

This paper aims to investigate the mechanical properties of polyurethane cement (different ratios) at different ambient temperatures. The temperature and proportion which affect the constitutive relation of the material were analyzed by axial tensile test. The microstructure and failure mode of polyurethane cement were studied using scanning electron microscope technology. At -40oC ~40oC, the stress-strain curves of polyurethane cement with different proportions were roughly similar. When the temperature was higher than 40oC, with the rise of temperature, the ultimate tensile strength of polyurethane cement specimens would decrease but the ultimate strain would increase. When the temperature was lower than -40oC, with the decline of temperature, the ultimate strain and tensile strength of polyurethane cement specimens would decrease. The ultimate stress of polyurethane cement with different ratios was different. With the rise of the proportion of polyurethane components, the ultimate stress would increase but the elastic modulus would decrease. Macroscopically, the failure modes of polyurethane specimens were different with the change of temperature. Brittle fracture occurred at low temperatures. At high temperatures, the specimen did not fracture, but a large number of “V”shaped cracks appeared at the edge. The higher the temperature, the more obvious this phenomenon was. At the microscopic level, the fibers didn`t break at high temperatures, and there were obvious cracks and more stubble on the surface of cracks at room temperature.