Composition Of Components Research Articles

Study on the critical conditions for ductile-brittle transition in ultrasonic-assisted grinding of SiC particle-reinforced Al-MMCs

High volume fraction (45 %) silicon carbide particle-reinforced aluminum matrix composites (SiCp/Al-MMCs) play a significant role in various engineering fields due to their outstanding performance. However, damages characterized by SiC particle fracture during machining lead to poor surface integrity, which severely affects the fatigue performance of SiCp/Al composite structural components. Ultrasonic-assisted grinding (UAG) is acknowledged as beneficial for promoting ductile grinding in hard and brittle materials. This study focuses on the critical conditions for ductile-brittle transition in ultrasonic-assisted grinding of SiCp/Al composites and develops a mechanism and data driven model of critical undeformed chip thickness (UCT) for ductile grinding to accurately predict the material removal mode. The model thoroughly integrates considerations of chip morphology, removal mode transition mechanism, and grinding surface damage characteristics. Response surface methodology (RSM) and genetic algorithms (GA) were utilized to correct the impact of processing parameters on the removal regime. Experiments on ultrasonic-assisted side and end grinding were conducted to thoroughly discuss the effects of different undeformed chip thicknesses, grinding speeds and ultrasonic vibration amplitude on surface damage and the critical conditions for the ductile-brittle transition. The findings corroborate the experimental data with the predicted values. Ultrasonic vibration can effectively reduce the brittle fracture of SiC particles in SiCp/Al composites. Appropriately increasing the grinding speed and reducing the chip thickness can enhance the critical chip thickness for ductile grinding and decrease the proportion of brittle surfaces, thereby achieving a balance between surface integrity and grinding efficiency. This research provides guidance for high-performance machining of SiCp/Al composites.

Comprehensive analysis of thermal performance and low-grade energy charging efficiency of pipe-embedded building envelopes enhanced with single-level tree-shaped fin structures

Pipe-embedded walls (CnPWs) are structural and energy composite building components that can resist external disturbances by forming stealth thermal shielding layers. To tackle the mismatch between the heat charging rate and heat diffusion rate during energy charging processes, as well as the unsatisfactory robustness of stealth thermal shielding layers, the single-level tree-shaped metal finnd pipe-embedded walls (TfPWs) are proposed. To verify the effectiveness of TfPWs and obtain dynamic performances, a simulation study is conducted on 8 risk variables in 4 pairs through the validated numerical model. Results showed that the improved design was effective in obtaining more robust thermal shielding layers in auxiliary energy supply mode, the effect gained prominence as both the injection temperature and pipe spacing were augmented. In room heat load reduction mode, favorable benefits arise when pipe spacing exceeds 400 mm. The maximum increase rate of total injected energy under different reduction ratios of external insulation layer was 11.83%–31.91 %, while the maximum extra total heat loss was 5.33 %. Secondly, the trunk fins and branch fins played different roles in minimizing the excessive heat accumulation surrounding pipes, and the vertical and horizontal sizes of heat accumulation region mainly increased with the increase in trunk fin size and branch fin size respectively. Meanwhile, the utilization efficiency of fin material was higher when trunk fin size was smaller, and parameter combinations with trunk fin size of 0.2b and branch fin size of 0.4a/0.6a could achieve a better balance between material input and performance increase. Thirdly, the improvement effect of single left branch fin schemes was close to that of double branch fin schemes and significantly better than that of single right branch fin schemes. It was recommended to use single left branch fin schemes with an inclination angle of 60°. Finally, even if the reduction ratio of external insulation layer in different cities increased to 80 %, the inside surface temperature of TfPWs was still greater than room air. Taking CnPWs with standard external insulation layer as references, the TfPWs applied in Harbin, Beijing, and Shanghai could achieve similar or better results even when the reduction ratio of external insulation layer increased to 60 %, while TfPWs applied in Guangzhou could exhibit better performance even when the reduction ratio of external insulation layer increases to 80 %.

Analysis of free amino acids and evaluation of the quality of gallnut honeys from different geographical areas

AbstractGallnut honey, a typical Chinese medicinal commodity, is produced from the nectar of Rhus chinensis Mill. Gallnut honey is very popular with consumers because of its health effects and nutritional value, but its specific nutritional composition and medicinal components are not clear. Free amino acids are important nutritional components of honey, and can provide relevant information about the honey, such as geographical and botanical origin, as well as adulterations. The aim of this paper was to explore the free amino acid characteristics of gallnut honeys in different areas. 18 free amino acids from 17 places in China were determined by automatic amino acid analyser analysis, and the geographical characteristics were studied by principal component analysis and cluster analysis. Results showed that gallnut honey is rich in free amino acids. A total of 12 types of free amino acids were detected in all honey-producing areas, and the total amino acid content was 0.132–0.292 g/100 g. Due to its free amino acid content gallnut honey has high nutritional supplement potential, and exhibits good pharmacodynamic activity and special taste characteristics. Flavour-related free amino acids were primarily aromatic free amino acids and umami free amino acids. Pharmacodynamic free amino acids accounted for 61.22–83.85%. Results also showed that free amino acids contribute to the geographical tracing of honey, and samples of gallnut honey at different altitudes can be distinguished by cluster analysis.

Freeform trajectory generation for fiber reinforced polymer composites additive manufacturing with variable-deposition-width

Continuous carbon fiber-reinforced polymers (CCFRPs) printing is a unique additive manufacturing (AM) technique that enhances design flexibility and enables on-demand production of lightweight, high-strength composite parts. However, current trajectory generation methods for CCFRPs-AM have limited control over fiber placement and flexible matrix path infill, particularly in complex regions, often using constant deposition widths that restrict path coverage and mechanical properties. To address these limitations, this paper presents a variable-deposition-width (VDW) trajectory generation method for CCFRPs-AM. The approach integrates a streamline-based technique for fiber paths with a Voronoi diagram-based method for matrix path generation, optimizing path placement based on 2D stress fields while accommodating user-defined fiber paths. Mechanical tests by us on fabricated open-hole composite components demonstrate that the proposed approach enhances the interfacial bonding and increases the maximal loading capacity under tensile stress.

The Relationship between Resting Metabolic Rate and Body Composition in People Living with Overweight and Obesity.

Background/Objectives: Resting metabolic rate (RMR) is an important contributor of energy balance and displays a well-documented relationship with sex, age, race and fat-free mass (FFM) in the existing scientific literature. However, the impact of other body composition components such as fat and liver fat on RMR remains unclear. This study aims to investigate the correlation of RMR with body composition parameters in a sample of patients with overweight and obesity. Methods: Retrospective data of patients with overweight or obesity referred for magnetic resonance imaging of liver fat during the period 2018-2023 were utilized for this study. Demographic and anthropometric data were collected, including body composition parameters (body fat, muscle mass) and RMR measured by bioelectrical impedance and indirect calorimetry, respectively. Results: The final sample included 53 patients (66% male), with a mean age of 48 years (±11.2) and a mean body mass index (ΒΜΙ) of 38.5 kg/m2 (32.7, 44.7). Simple correlation models revealed that RMR was separately correlated with gender, age, BMI, muscle mass, and liver fat (all p < 0.05) but not with fat mass. When multiple regression models were employed, only muscle mass retained its statistically significant influence on RMR, while total and hepatic fat did not significantly affect RMR after controlling for other parameters (gender, age, muscle mass). Conclusions: These findings confirm the known correlation between muscle mass and RMR while highlighting the lack of association between total and hepatic fat and RMR in individuals with overweight and obesity.

A friction-based method for measuring the radial compaction response of fibre tows

High performance fibre reinforced composite components are typically compacted to a high fibre volume fraction during manufacture. As such, it is important to understand the compaction behaviour of these materials to better design and model composite manufacturing processes. While most manufacturing processes apply transverse compaction pressure to planar textiles, continuous fibre composite 3D printing processes can apply a radial compaction pressure to a single tow in the printing nozzle. A similar mode of compaction is also seen in processes such as pultrusion of circular cross-sections. This work describes a new friction-based method for measuring the radial compaction response of single tows, or groups of tows. The radial compaction behaviour of a single 40K carbon fibre tow is measured and presented. Radial compaction of the characterised tow showed a steeper nonlinear relationship between compaction pressure and fibre volume fraction, than typically found for transverse compaction of 2D textile reinforcements.

Tailoring Failure Interactions for Validation Testing of Composite Laminate Progressive Failure Models

Efficient validation of numerical models for predicting failures in composite structures is imperative due to the intricate nature of such failures. The multifaceted aspects, including multimodal, multiscale, and interactive factors, pose challenges in the calibration and validation of models. Constraints in cost and time often limit the comprehensive testing required for model validation across diverse failure response scenarios. This study proposes an optimal test selection approach, building upon previous insights that optimizing measures derived from progressive failure responses can unveil failure mode interactions sensitive to stochastic variations. Calibration designs should minimize interaction while maximizing sensitivity to calibration parameters, whereas validation models must encompass varied interactions to understand predictability limits. However, optimizing progressive failure analyses for composites is computationally intensive. A straightforward design of experiments exploration is demonstrated here, focusing on efficiently identifying designs sensitive to stochastic effects, which reveal mode interactions and suitability for calibration/validation. This method is exemplified using computational models for composite bolted joints subjected to pin-bearing loads, showcasing their intricate failure modes. Designs displaying high sensitivity to parameter changes offer insights into failure mechanisms, aiding in model validation and enhancement. Thus, employing such critical designs as test cases can refine numerical models, resulting in more accurate representations of complex failure behaviors in diverse composite components.

Subtractive manufacturing of composite materials with robotic manipulators: a comprehensive review

AbstractRobotic manipulators play an innovative role as a new method for high-precision, large-scale manufacturing of composite components. However, machining composite materials with these systems presents unique challenges. Unlike traditional monolithic materials, composites exhibit complex behaviour and inconsistent results during machining. Additionally, robotic manipulator as a machine tool often associates with stiffness and vibration issues which adds another layer of complexity to this approach. By employing a comprehensive analysis and a combination of quantitative and qualitative review methodology, this review paper aims to survey diverse properties of composite materials by different categories and their interaction with machining processes. Subsequently, a survey of manufacturing techniques for composite machining following with a review in various modeling practices to capture material machining behaviour under a systematic framework is presented. Thereafter, the reviewed literature examines the errors inherent in robotic systems, alongside ongoing research efforts in modeling to characterise robot behaviour and enhance its performance. Afterward, the paper explores the application of data-driven modelling methods, with a primary focus on digital twins, in enabling real-time monitoring and process optimisation. Finally, this paper aims to identify the gap in this field and suggests the potential routes for future research and application as well as their challenges.

Chromatographic Methods in the Identification and Determination of the Component Composition and Quality of Wines

Chromatographic Methods in the Identification and Determination of the Component Composition and Quality of Wines

Objectives for the use of raw materials and component composition for the production of low-lactose ice cream from goat milk

A huge number of people all over the world suffer from lactose intolerance. The second problem is an allergy to cow milk protein. People with lactose intolerance, as well as those who suffer from cow milk allergies, are forced to significantly limit their choice of ice cream or give it up completely. The article describes a solution to the problem of eating ice cream by children and adults suffering from lactose intolerance and an allergy to cow milk protein, and presents ways to overcome it.The goal of the research. Objectives for the use of raw materials and component composition for the production of low-lactose ice cream from goat milk. During the research, the quality indicators of the selected raw materials have been studied, the characteristics of the main ingredients for the production of low-lactose ice cream have been substantiated and given. Goat milk, in terms of its quality indicators, is most suitable for the production of ice cream, because it contains more protein, fat, solids, less lactose and does not cause allergies, and therefore it has been chosen as the main raw material for the production of ice cream. A theoretical and practical analysis of the chemical composition and properties of goat milk has been carried out, and compared with cow. To reduce the lactose content, a dual method of lactose hydrolysis has been chosen - the use of probiotic starter cultures and the lactase enzyme. In the process of combined hydrolysis at a temperature of 37-39⁰ C for 4-6 hours, a reduction in lactose content of less than 0.9% is achieved, while the concentration of cells of probiotic microorganisms in active form reaches 108 CFU/cm3. It is proposed to use the “Lactomix KM” stabilization system, which is usually used in the production of fermented milk products.

КЕРАМИКАЛЫҚ ЖОЛ ТӨСЕНІШТЕРДІ ӨНДІРУДЕГІ КЕРАМИКАЛЫҚ МАССА КОМПОЗИЦИЯСЫН ЖЕТІЛДІРУ

The article presents the results of a study of the chemical and mineralogical composition of the raw material components in the ceramic mass and provides techniques for the technology of laying ceramic material by vibropressing using talc rock in the mass and methods for determining the composition of clay raw materials. Formulations for the production of ceramic road surfaces, taking into account the factors of preference for mixtures to improve the properties of the finished product as a molding, drying and ceramic material, have been studied in two different components. It was found that the introduction of talc into the ceramic composition has an effect on the formation of high-temperature augite and amphibole phases and the intensification of the formation of minerals in clay, on the formation of high-temperature phases - sanidine, ackermanite elements. This process leads to an increase in the physical and mechanical properties of the resulting samples.The main patterns of formation of the structure and phase of ceramic compositions by firing in the temperature range 1000оC-1100оC were studied by isothermal control.In this pattern, sintering processes with solid and solid liquid-phase syntheses were carried out to ensure the phase - mineral composition, the study clarified the production of high-strength and frost-resistant ceramic pavement. In order to be used in the improvement of the city territory (sidewalks, alleys, park areas, playgrounds, etc.), the possibility of obtaining ceramic road surfaces that meet environmental and operational requirements has been proven. It has been established that one of the priority properties of ceramic road surfaces is a significant abundance of their porosity (25-30%), which allows you to quickly absorb moisture from precipitation (rain, sleet, etc.) and filter water through the body into the ground.Such properties of ceramic paving stones prevent the accumulation of moisture on the surface of the roadway and create comfortable conditions during pedestrian movement, reducing the likelihood of ice formation on the surface of the paving stones in the cold season.

Investigating the chemical composition, digestion and fermentation of Alternanthera sessilis red plant and its effect on the performance of fattening lambs.

The present experiment was conducted to evaluate the nutritional value of red Alternanthera sessilis for fattening lambs when they were replaced with alfalfa forage. Forty growing lambs with an average weight of 21.12kg and an age of 5 months were randomly assigned to four experimental treatments. Growth performance, nutrient digestibility, rumen fermentation parameters, protozoa population, blood parameters, and composition of carcass components were evaluated. The results of this experiment showed that the use of Alternanthera sessilis in the diet significantly reduced feed intake, increased the average daily weight gain, and improved the feed conversion ratio compared to the control treatment (P < 0.05). The digestibility of dry matter and protein was significantly increased (P < 0.05), while the digestibility of neutral detergent fiber, acid detergent fiber, and organic matter showed a numerical increase. Diets containing different levels of the Alternanthera sessilis plant did not affect pH, but the increase in the amount of this plant in the diet led to an increase ammonia nitrogen concentration and rumen protozoa population (P < 0.05). The addition of Alternanthera sessilis to the diet significantly reduced the concentration of blood glucose and cholesterol and increased the concentration of blood urea nitrogen (P < 0.05). Except for the weight of the thigh and neck, the effect of experimental treatments on other carcass components was not significant. Overall, the results of this experiment showed that using the Alternanthera sessilis plant in the rations of fattened lambs as a substitute for alfalfa forage not only had no negative effect on the studied parameters but also improved them in some cases. Therefore, Alternanthera sessilis can be used in rations of fattened lambs as a substitute for part of alfalfa forage.

Thermodynamic analysis of interactions between the components of the charge during the production of metallurgical silicon

The theoretical foundations of the recovery process and the technology of silicon smelting in electric arc furnaces are considered. The results of a study of thermodynamics, reaction kinetics, and mechanisms of the melting process are presented. Production issues are covered: charge preparation, smelting, refining, gas purification. Physicochemical models of the carbothermal process were developed, proposed and tested under industrial conditions (Tau-Ken-Temir LLP), which made it possible to assess the influence of the specified technological parameters of the smelting (chemical composition and loading coefficients of charge components, temperature) on silicon recovery and grade. To obtain the base material, metallurgical grade silicon is used, obtained by melting in ore-thermal furnaces (RTP). In this regard, the research goal is determined, which consists in studying ways to improve the quality (chemical purity) of silicon, and methods for achieving it at this stage of the study - modeling the carbothermal process for producing silicon.The article describes the main mechanism for the recovery of silica in the furnace, presents one of the designs of the furnace and the technological scheme for the production of silicon. The author suggested studying the process of producing metallurgical silicon in RTP using the HSC Chemistry software package. A model of silicon smelting in RTP was formed, which adequately describes the technological process for producing metallurgical silicon.

Очистка торфяных грунтовых вод методом ультрафильтрации и ионного обмена

Purpose: assessing the effectiveness of peat groundwater purification using a combination of two methods of ultrafiltration and membrane purification. Identify specific characteristics of the composition of peat or groundwater, determine possible possible methods of treating these waters to ensure compliance with the requirements of SanPiN 2.1.3684–21 “Sanitary and epidemiological requirements for the maintenance of territories of urban and rural settlements, for water bodies, drinking water and drinking water supply to the population, atmospheric air, soil, residential premises, operation of industrial and public premises, organization and implementation of sanitary and anti-epidemic (preventive) measures” to the quality of drinking water. Determine the list of composition indicators that require cleaning. Conduct an assessment of wastewater treatment methods used to treat peat groundwater. Togo, Conduct research on the composition of purified groundwater before and after treatment, determine the effectiveness of the treatment methods used according to various indicators. Determination of the concentrations of groundwater composition components was carried out using approved methods in accordance with GOST R 57164-2010 clause 5; GOST R 57164-2010 clause 6; PND F 14.1:2:4.207-04; PND F 14.1.2:3:4.121-97; PND F 14.1:2:4.114-97; GOST 31594-2012 Method A; PND F 14.1:2:4.50-96; PND F 14.1.2:3:4.111-97; PND F 14.1.2:3:4.111- 97; PND F 14.1.2:3.154-99; PND F 14.1.2:3:4.123-97; GOST 31859-2012; PND F 14.1.2:3:4.4-95; GOST 31940-2012 clause 6; PND F 14.1.2:4.178-02; PND F 14.1.2:4.214-06. An analysis of the results of laboratory studies of the composition of peat groundwater before and after treatment was carried out, and the effectiveness of ultrafiltration and membrane water purification methods was determined. The results of studies of the effectiveness of purification of peat groundwater using ultrafiltration and membrane purification methods show that purified groundwater meets the sanitary and epidemiological requirements for the quality of drinking and domestic water supply established by SanPiN 2.1.3684-21. Practical significance: the results obtained from studies of the effectiveness of peat groundwater treatment using ultrafiltration and membrane treatment methods indicate the possibility of using these methods, because they ensure that water quality meets the requirements of SanPiN 2.1.3684-21.

Insights into the pelletization behaviors of artificial lignocellulosic biomass based on cellulose, hemicellulose and lignin: A simplex lattice mixture design approach

The use of high quality densified pellet as an alternative to traditional fossil fuels is a promising avenue of research due to their interesting higher density, superior heating values, and enhanced combustion performance. However, little is known about the pelletization behaviors from the aspect of lignocellulosic biomass fundamental components (cellulose, hemicellulose and lignin) and their mixtures. This study presents an artificial biomass developed based on cellulose, hemicellulose and lignin using a simplex lattice design approach, aiming to understand the detailed role of major components and its effects on pellet quality. The correlation between the experimental data obtained from the simplex lattice design and the predicted response parameters were effectively explained by Scheffé's special cubic model, with a coefficient of determination beyond 90 %. Parameter estimates showed a significant synergetic effect of each components for density and Meyer hardness. Results revealed that xylan may be softened like lignin and thereby potentially act as binder. The use of a high cellulose concentration resulted in enhanced pellet strength by acting as a supporting skeleton. Xylan and cellulose played a major role in the thermal degradation of densified pellets. Based on the results obtained, the optimal components composition was determined to be 34.5 % lignin, 36.3 % cellulose, and 29.2 % xylan. Under this, the pellet exhibited the best density and Meyer hardness beyond 1500 kg/m3 and 80 N/mm2, respectively. The results provide a foundation for future efforts to be able to predict pellet properties from the perspective of biomass composition.

CO-PROCESSING OF COTTON SOAPSTOCK, COAL DUST AND POLYMER WASTE BY PYROLYSIS METHOD

The work is aimed at solving the problems of rational consumption of secondary raw materials on the basis of carbon-containing waste of industries, saturation of the market with additional products and protection of the environment from the toxic effects of waste. Aim of work: the study of the co-pyrolysis process of gossypol resin (GR) from cotton soapstock of "Shymkentmay" JSC, coal dust (CD) of Kulan deposit and plastics waste (PW) in N2 medium. The methodology of work included the establishment of optimal modes of the process, determination of yield, composition and properties of pyrolysis products. Analysis of pyrolysis products by IR spectroscopy, XRD, chromatomass spectrometry. Study of the component composition of liquid pyrolysis products by the method of extraction separation in Soxhlet apparatus into oils, asphaltenes and resins. Assessment of perspectivity of co- pyrolytic processing of carbon-containing wastes from different industries for industrial development. Results and discussion. The optimum temperature of GR pyrolysis (T=450 ⁰С) was established, at which the yield of liquid product was on average 33.01 wt.%, gas yield – 60.33 wt.%, yield of solid residue – 6.65 wt.%. The co-pyrolysis of GR and CD at 1:1 ratio and T=500 ⁰C in N2 atmosphere was investigated for the first time. A high yield of liquid product – 47.34 wt.%, low gas formation – 2.31 wt.% and a large amount of solid residue – 50.34 wt.% were observed, which is apparently due to the formation of coal semicoke and coke. The process of co- pyrolysis of GR, CD with D=90 μm and PW (PE:HPPP – 1:1) at the ratio of 1:1:1 and temperatures of 500 ⁰С-700 ⁰С in N2 atmosphere was investigated for the first time. It is shown that the main contribution to the formation of liquid products in the given temperature regimes is made by GR and PW. Conclusion. Co-processing of carbon-containing wastes was found to be of interest and practical importance, both in terms of obtaining marketable products and maintaining a safe ecology.

The effect of functional ingredients on the quality of the curd product and its storage capacity

The solution to the problem of rationalizing the nutrition of the population, reducing the negative impact on the human body of harmful factors (physical, chemical) of the external environment is possible by creating functional products that include proteins, vitamins, antioxidants, pectins and other essential nutrients, the deficiency of which has been noted by biomedical research. Based on theoretical and experimental studies, the components were selected including functional ingredients: zosterin – a natural polysaccharide and vegetable filler – honeysuckle berry juice. Low-fat cottage cheese, which includes proteins, minerals, sulfur-containing compounds and other substances, was chosen as the basis of the functional product. As a result of the conducted research, technological approaches were formed and the component composition of the curd product with zosterin and berry juice was justified. The ratios of zosterol and honeysuckle juice in relation to the mass of cottage cheese have been established, ensuring proper technological and preventive effect. The organoleptic, structural-mechanical, physico-chemical parameters of the curd product have been studied. The nutritional and energy value is calculated. The developed curd product has an increased nutritional value, it contains biologically important components – vitamins, mineral salts, polyphenolic substances, pectins. It has a high digestibility due to the homogenization of all components and complementary organoleptics: pleasant aroma and taste, homogeneous, delicate consistency, attractive external characteristics. The effect of zosterol and berry juice on the quality of the curd product during storage has been studied. It has been proven that the introduction of zosterol and berry juice allows you to slow down undesirable processes, and, consequently, extend the shelf life of the product.

Predicting the fatigue life of T800 carbon fiber composite structural component based on fatigue experiments of unidirectional laminates

This study is based on the fatigue experiment results of unidirectional laminates and investigates the fatigue performance of T800 carbon fiber/epoxy resin composite structural components through experimental and numerical analysis. Fatigue experiments were performed on [0]16, [90]16, and [±45]8 laminates individually, obtaining the fundamental fatigue parameters necessary for modeling. The fatigue life model for T800 carbon fiber/epoxy resin unidirectional laminates was refined, and fatigue degradation rules were provided for the fatigue progressive damage model. A fatigue progressive damage analysis model for T800 laminates was established based on the 3D Hashin criterion, predicting the fatigue life and fatigue damage failure process of the laminates. A fatigue life prediction model was developed for T800 carbon fiber composite I-beam structural components, which can predict the primary types of fatigue failure, fatigue life and the location of fatigue failure occurrence. The predicted fatigue life of structural components shows good consistency with the experimental results. This method can calculate structural components including ply angles of 0°, 45°, and 90° and obtain the fatigue life contour.

PREDICTION OF STRENGTH DEPENDING ON THE INFLUENCE OF THE CHEMICAL COMPOSITION IN THE 40КХНМ ALLOY

Introduction. The study is devoted to the analysis of the influence of the chemical composition of the 40КХНМ alloy on its hardness. The relevance of the work lies in the fact that mechanical tests require significant material and time costs. For the operational assessment of metal quality criteria, it is proposed to apply mathematical modeling in the work. Materials and methods. A study of the effect of the chemical composition on the hardness of the 40KHNM alloy, which meets the requirements of the state standard 51397, was carried out. The results of the experiment. In the course of research, it was found that changes in the chemical composition of the 40КХНМ alloy significantly affect its mechanical properties, including hardness and resistance to shock loads. An increase in the content of carbon, molybdenum and chromium in the alloy leads to an increase in its hardness. This is with the formation of stronger carbide and molybdenum phases in the structure of the alloy, which leads to an improvement in its mechanical properties. Increased hardness makes the alloy more resistant to wear and increases its durability in operating conditions. An increase in the nickel content in the alloy leads to an increase in its resistance to shock loads. This is caused by an increase in plasticity and impact toughness of the alloy with an increased nickel content. Higher resistance to shock loads makes the alloy suitable for use in conditions that require high resistance to shocks, for example, in the production of machine parts and equipment. A mathematical model of the dependence of the strength of the alloy on the percentage content of the components of the chemical composition was built, which allows to control the indicators of the strength of the alloy in the process of its manufacture. Conclusions. The research results confirm that changes in the chemical composition of the 40КХНМ alloy have a significant impact on its mechanical properties. As a result of the experiments, it was established that the chemical composition of the metal significantly affects the hardness of the material. By changing the composition of the metal, it was possible to achieve a significant increase in hardness to levels that meet the requirements of quality standards. These results are an important step in optimizing the production processes and improving the properties of the final products from the 40КХНМ alloy.

Tribotechnical processes of the soil environment interaction with the working bodies of soil tillage and earthmoving machines reinforced with composite materials

The work presents the study results of the stress-strain state of the soil, as a continuous medium filled with abrasive particles under the action of the working bodies of soil tillage and earthmoving machines. One of the main properties of the soil, which determines the specifics of the force interaction of the working surfaces of the working bodies of soil tillage and earthmoving machines with the technological environment, is taken into account, namely the tendency of the contact layer of the treated layer to compaction. The relationship between stress in the soil and the wear of the working bodies of soil tillage and earthmoving machines has been established experimentally. A theoretical analysis is presented for the stress-strain state of the local region of the strengthened surface layer that is used in the working bodies of soil tillage and earthmoving machines, in which the filler, inclusion or strengthening phase is placed. An analysis of the contact characteristics of the stress-strain state and their changes during friction and wear was carried out based on the formulation and solution of the contact interaction problems of abrasive soil particles with the inhomogeneities of the composite coatings components based on ultra-high molecular weight polyethylene with fillers during strengthening of the working bodies of soil tillage and earthmoving machines. Computer modeling was performed to study the nature of stress distribution in the reinforced surface layer of the working bodies of soil tillage and earthmoving machines in the area of the contact zone in stationary and dynamic conditions. The contact problem is formulated, the boundary conditions and the solution in the form of components of the stress field are given. The characteristics of the filler, their content in the composite material and coating are taken into account, the relationship between the stress-strain state and wear is established.