Characterization of Counter-Surface Substrates for a Laboratory Abrasion Tester (LAT100) Compared with Asphalt and Concrete to Predict Car Tire Performance

Tire performance is determined based on the interaction between the tire and the road as a counter-surface, and is of the utmost importance for driving safety. When studying tire friction and abrasion, the characteristics of the roads/counter-surfaces are crucial. The excitations on the tire come from the road asperities. A proper characterization of the counter-surface texture is, therefore, an absolute necessity in order to optimize tire performance. The present study provides the required knowledge over the counter-surfaces employed as common substrates in a Laboratory Abrasion Tester (LAT100), which are typically based on embedded corundum particles for dry/wet friction and abrasion experiments. All surfaces are scanned and characterized by laser microscopy. The surface micro and macro roughness/textures are evaluated and compared with asphalt and concrete as the real roads by power spectral densities (PSD). The reliability of the high-frequency data based on the device type should be considered carefully. The reliable cut-off wavenumber of the PSDs is investigated based on image analyses on the range of tested frequency for micro and macro textures obtained by optical scanning devices. The influence of the texture wavelength range on the rubber−surface interaction is studied on a laboratory scale.

Determining patterns in the use of finishing formulations for trimming the Crust leather

This paper has considered the possibility of using new finishing formulations to finish the Crust leather, manufactured from cattle raw materials aimed to finish shoes and leather garments.The quality indicators of finishing formulations and their elementary chemical composition have been investigated. It was found that the finishing formulations possess a high covering capacity due to the presence of mineral pigments in their composition. X-ray fluorescent analysis has proven that the presence of chromium pigments and copper compounds renders the green color to the composition; the compounds of cobalt, copper, iron, chromium ‒ blue color; cobalt compounds ‒ reddish-brown color.It has been established that the finishing formulations are resistant to the effect of electrolytes of different nature over a wide pH interval, from 2 to 11.When determining the uniformity of the composition by using a chromatography method involving fan-shaped paper, it was found that the composition of blue has a pronounced purple hue, of reddish-brown – red.The effectiveness of the use of finishing formulations to finish the Crust leather has been proven by determining the indicators of its quality. The finishing formulations give the Crust high resistance to dry (exceeding 500 rotations) and wet friction (exceeding 150 rotations), multiple bending (exceeding 50,000 rotations), the effect of water (2 to 5 points), and organic solvents (2 to 4 points). At the same time, the finishing formulations are characterized by rapid diffusion into the structure of the leather with a natural front surface with the simultaneous provision of specific properties to it. Specifically: water-repelling properties (hydrophobicity), shine, wax grain, matte, saturated homogeneous color. The leather with the introduced finishing formulations does not require fixing the resulting coating with water-based varnish.It is recommended to use the finishing formulations in the production of Crust leather shoe top by applying them onto the surface by spraying or using a brush to create the desired effect

Studying the similarities of deformation properties of leather materials in the process of creating a model of shoes

Determination of values and dependencies of deformation and physical and mechanical properties of materials of shoe models and finished products. According to the results of theoretical, analytical and marketing research, a number of experimental tests of materials have been carried out to prove the practical significance of the work, namely tests for: deformation of the vamp part of the product, uniaxial and biaxial stretching, bending, dry and wet friction, adhesion, elongation and tearing. There has been established the nature of the distribution of the total elongations of the samples of the vamps cut from different areas of the leather, as well as the ability of the leather material to be formed when improving the shape of the product or changing the shape of the shoetree. The processes of deformation of the vamp part of shoe blanks, physical and mechanical properties of different groups of modern materials and values analysis of similarity of their deformation properties have been studied. There has been created a working model-transformer for carrying out preliminary measurement of clients’ feet at the individual order. The expediency of these works has been proved experimentally. A working version of a model-transformer for foot measurements has been made and as a result of the works approbation, a sample of shoes has been made. The ergonomic properties of the manufactured footwear have been improved due to the use of materials with enhanced physical and mechanical properties. The article investigates the deformation of the most vulnerable vamp part of the men's model of a typical model, as well as the physical and mechanical characteristics of leather materials for manufacturing models and shoes of this type. Providing high quality and comfort of footwear, accuracy of parameters selection of foot measurement, zones of beams and achievement of form stability of footwear with a top from genuine leathers has been predicted.

Condition Monitoring Method for Automatic Transmission Clutches

This paper presents the development of a condition monitoring method for wet friction clutches which might be useful for automatic transmission applications. The method is developedbased on quantifying the change of the relative rotational velocity signal measured between the input and output shaft of a clutch. Prior to quantifying the change, the raw velocity signal is preprocessed to capture the relative velocity signal of interest. Three dimensionless parameters, namely the normalized engagement duration, the normalized Euclidean distance and the spectral angle mapper distance, that can be easily extracted from the signal of interest are proposed in this paper to quantify the change. In order to experimentally evaluate and verify the potential of the proposed method, clutches’ life data obtained by conducting accelerated life tests on some commercial clutches with different lining friction materials using a fully instrumented SAE#2 test setup, are utilized for this purpose. The aforementioned parameters extracted from the experimental data clearly exhibit progressive changes during the clutch service life and are well correlated with the evolution of the mean coefficient of friction (COF), which can be seen as a reference feature. Hence, the quantities proposed in this paper can therefore be seen as principle features that may enable us to monitor and assess the condition of wet friction clutches.