Fulltext search in archive

Titanium alloy Ti6Al4V fabricated using Selective Laser Melting (SLM) has gained significant attention in biomedical and aerospace applications due to its superior mechanical properties and design flexibility. However, its machining characteristics, particularly in milling, remain challenging due to the material's hardness and thermal conductivity. This study investigates the milling performance of SLM-manufactured Ti6Al4V by optimizing surface roughness using the Taguchi method. An L9 orthogonal array was employed, considering spindle speed, feed rate, and depth of cut as control factors. Surface roughness measurements were analyzed using Signal-to-Noise (S/N) ratios, and Analysis of Variance (ANOVA). Results indicate that spindle speed significantly affects surface roughness, contributing over 83.67% of the total variation. The optimized milling parameters resulted in a notable improvement in surface quality, highlighting the effectiveness of the Taguchi method in achieving better machinability for additively manufactured titanium alloys. This study offers useful insights to improve the milling process of SLM-made Ti6Al4V, helping boost performance in industrial use.

The article deals with the experimental measurement of the load on the cervical vertebrae when driving a passenger car over bumps. The measurement was done experimentally. The load on the human spine was measured in the area of the C7 cervical vertebra and also in the area of the top of the head. Vehicle crossings over speed bumps. The measurement was carried out at different crossing speeds and at different heights of speed bumps. Three-axis acceleration sensors were placed on selected parts of the vehicle and on the human body. The proposed measurement methodology was verified by the conducted pilot experiment for the possibility of conducting further experiments. The results of the work showed that the crew of vehicles in road transport is more stressed than previous scientific findings indicate.

Aiming at the problem of feature extraction and fault recognition for rolling bearings, a fault diagnosis mthod based on multi-scale entropy and ensemble learning is proposed in this paper. Firstly, the variable mode decomposition algorithm is used to decompose the vibration signal, and then the cross-correlation number method is used to reconstruct the signal to realize the signal denoising. Subsequently, in order to improve the effectiveness of feature extraction for rolling bearings, a feature extraction method based on Refined Composite Multiscale Reverse Permutation Entropy (RCMRPE) is proposed. Then, in order to improve the accuracy of rolling bearing fault identification, this paper proposes a fault diagnosis model based on Stacking- CatBoost ensemble learning. Finally, relevant experiments were conducted on signal denoising, feature extraction, and fault recognition. The RCMRPE entropy extraction method was compared with the common entropy extraction methods, and the proposed fault diagnosis model was compared with the common machine learning models. The experimental results show that the feature extraction error based on RCMRPE is small and can comprehensively reflect the actual fault information of bearings; the accuracy and recall of the fault diagnosis model based on Stacking- CatBoost ensemble learning are both above 99%, and the diagnostic effect is significantly better than other models.

Manufacturing inaccuracies in vehicle suspension systems inevitably lead to uncertainties in the parameters of their structural components. Simultaneously, the road excitation impacting nonlinear vehicle systems exhibits pronounced randomness and time-variant characteristics. Consequently, it is crucial to conduct a stochastic dynamics analysis on nonlinear suspension systems, taking into account these uncertain factors. In this paper, a seven-degree-of-freedom (7-DOF) nonlinear suspension system dynamics model has been established. The stochastic process of road irregularities is simulated using the harmonic superposition method. Moreover, based on the direct probability density integral method, the stochastic dynamic equations of the nonlinear suspension system and their corresponding solution strategies have been developed and explored. Through MATLAB, the time-varying probability density function of the vibration response for a nonlinear vehicle suspension system was calculated under the combined effects of stochastic road irregularity excitation and random coupling of system structural parameters. Additionally, analyses were conducted on how different coefficients of variation and the intensity of nonlinearity in the suspension system influence the probability density of the output body displacement of the nonlinear vehicle suspension system. The research outcomes demonstrate that the direct probability density integral method offers superior efficiency and accuracy when computing nonlinear vehicle suspension systems. Furthermore, altering the coefficients of variation for various system parameters reveals that as these coefficients increase, the disparity in the probability density of body displacement becomes more pronounced, leading to more intense vehicle vibrations. Under soft nonlinear conditions with lower suspension spring stiffness, the probability density function of body displacement shifts slightly to the right with minimal change. However, under strong nonlinear conditions, body displacement significantly increases, resulting in diminished vibration isolation capabilities of the suspension system. This leads to severe jolts and a noticeable decline in ride comfort during vehicle operation.

Unfortunately, in connection with the application of the Actavia anti-plagiarism system, we cannot accurately describe our paper, which deals with the production of non-compact materials based on zinc and tin alloys, which have a higher density than aluminium (ρ = 2700 kg.m^-3 ) and its alloys, such as zinc alloys (ρ = 6980 kg.m^-3 ) or tin (ρ = 7580 kg.m^-3 ). Test samples were prepared from these materials, which were characterized by material non-compactness based on the use of NaCl particles. For this purpose, two different size groups of NaCl particles (3 to 5 mm and 5 to 7 mm) were used. In the production of non-compact metallic materials, it is assumed that half of the volume of the workpiece cavity will be occupied by NaCl particles and half of the volume of the work piece cavity will be filled with a melt of the relevant alloy (ZnAl4Cu1 or Sn89Pb). This is different from our previous experiments [24, 25]. In the case of this paper, the fabrication consisted in the fact that in a spe-cial preparation, the melt of the respective alloy was forced between the NaCl particles. The produced samples of non-compact material were analyzed and their specific gravities were determined. In a standard manner (as may be against the findings of the Actavia system), the microstructure was observed on an electron microscope and EDS analysis was also performed. It is anticipated that the non-compact materials thus produced from these two alloys will be used to produce not only filters but also bodies for liquid hydrogen storage.

In the realm of engineering the quest for optimization is ceaseless. This article explores the intricate relation-ship between cubic equations and the practical world of production technologies, unearthing the profound connections that underpin mathematical symmetry and its role in engineering. Cubic equations, often arising in the analysis of mechanical systems, electric circuits, and robotics, serve as indispensable tools for under-standing and enhancing real-world applications. This study delves into the methods for finding the roots of cubic equations, shedding light on the vital role of mathematics in engineering and manufacturing technology.

The aim of the research was to assess the influence of additions of different proportions of alumini-um waste chips from the machining technology on the melt quality and final properties of AlSi7Mg0.3 alloy casts. All casts were created using by gravity casting technology into preheated metal mold. The first cast was a pure AlSi7Mg0.3 alloy, followed by other samples with contents of 10, 30, 50, 70 wt.% of aluminum waste chips in the batches. All the samples were subjected to the Brinnel hardness and Vickers microhardness of solid solution of α(Al). Also, Density index was measured. At the end of research, the microstructures of the samples were analyzed using a Laser Confocal Microscope Olympus Lext OLS 5000.

Over the last decades, nickel-based superalloys with TBC coatings have been used as the main material for hot section turbine parts. The next step in the development of engines and increasing the combustion temperature is the use of Ceramic Matrix Composites (CMC). Nevertheless, in the presence of water vapour or molten salts, accelerated degradation of substrate material. This problems can be pre-vented by additional layers or coatings produced on its surface, or combinations of layers and coatings that form Environmental Barrier Coatings (EBCs). The aim of the research was the preparation of sam-ples of a mixture of erbium oxide powders with silicon oxide with the addition of: polyvinyl alcohol, starch and cellulose gum. Then their technological properties were examined. A mixture with the most favourable properties was selected and sprayed using HV-APS method using with various process parameters and investigated. Conducted research showed that energy of HV-APS process is too low for synthesis of erbium disilicate in the resulting coating. The material was only melted, not vaporized. Making powder agglomerates with an average size of 150 μm with the addition of 3% PVA leads to a significant decrease in the surface area of powder grains. This results in a significant increase in flowability and allows it to be used as a charge material for APS plasma spraying.

Laser cladding technology, a novel surface modification technique, is widely employed in tasks such as metal surface strengthening and repair. However, the quality post-cladding often falls short of usage requirements, harbouring defects like cracks and pores. In pursuit of a crack-free cladding method, surface texture technology is integrated with laser cladding technology to establish a multi-field coupled numerical simulation model. This model investigates the temperature, stress, and fluid fields during laser cladding with and without texture, aiming to identify the optimal cladding parameters. The results indicate that the optimal cladding parameters are a laser power of 1200 W, a scanning speed of 7 mm.s^-1, and a spot radius of 2 mm. In comparison with cladding without texture, the minimum temperature has increased by approximately 50 %, while the peak temperature has remained almost unchanged. The maximum residual stress of the cladding layer without texture is 369.46 MPa, whereas that of the cladding layer with pre-set texture is 338.46 MPa, representing a reduction of approximately 8.39 %. The bottom of the cladding layer has decreased by about 29.1 %, effectively enhancing the mechanical properties at the metallurgical bond of the cladding layer. The pre-set texture induces a decreasing trend in the flow velocity inside the molten pool, eliminating the double-vortex effect, and resulting in a more uniform temperature distribution within the molten pool, consequently reducing the residual stress of the cladding layer. This paper employs multi-field coupled numerical simulation technology to monitor the internal state of the molten pool, offering insights for enhancing the quality of the cladding layer in subsequent endeavours.

This paper describes β-Sn to α-Sn transformation in its initial phase. This process is also known as a tin pest and currently it causes problems mainly in the field of soldering materials. To avoid misrepresenta-tion of the results of artificial ageing of the samples; we have decided to use historical materials for our study. A sample from historical organ pipes was indented by naturally formed α-Sn polycrystalline parti-cles by the load of 1 kg. The sample in the initial state was observed by SEM and analysed by EBSD mapping. The position of inoculator particles was documented again by SEM observation. Subseqently, the sample was freezed at -50 °C. The evolution of cracks started after 2.5h in the vicinity of indented α-Sn particle. After 5 h of freezing, new cracks were observed also in the untouched parts of the sample. The crystallografical interconnectedness was not proven for polycrystalline samples.

The geometric accuracy of a machine is primarily determined by the accuracy of assembly, manufactur-ing, and overall setup. Standardized procedures for assessing geometric accuracy are established and detailed in delivery protocols for various types of machining machines. To effectively monitor and ana-lyze machining machine errors, the most suitable approach is to construct a comprehensive error balance that accounts for the overall performance of the machine. This error balance methodology, a tool within the realm of system analysis, is utilized for predicting and managing systemic errors. The errors ob-served in machined components are intimately connected to the errors present in the machining ma-chines themselves. These errors are further intertwined with the design and physical properties of indi-vidual machine components, as well as their interactions. In the case of multi-axis machines, they col-lectively determine the overall accuracy of the produced components. The objective of this study is to analyze machining machine errors using the Renishaw XL-80 laser interferometric system. The findings of this study reveal that errors in machining machines can also be the result of the dynamics of the cut-ting process, which may have a significant impact on accuracy.

Composite materials have consistently been applied in areas where a combination of properties such as strength, stiffness, and low weight is crucial. Motorcycle construction is no exception, as these parameters significantly impact riding characteristics, safety, and overall performance. This article focuses on quantifying the torsional and vertical stiffness of a single-sided swingarm made of carbon fiber reinforced polymer (CFRP) using finite element analysis (FEA) and verifying these results through experimental measurements. To enhance the accuracy of the simulations, which involve complex geometries and anisotropic materials, the material properties of selected fabrics used in the prototype production were measured. Specific fixtures were designed for the experimental measurements, enabling the application of torsional moments and vertical forces. Deformation under these loads was evaluated using the TRITOP photogrammetric system, which tracks deformations by monitoring the displacement of reference points under static load conditions and comparing them to a reference, unloaded state. Based on the acquired data, the overall stiffness values and their distribution along the length of the swingarm were calculated. The results showed a significant difference between simulation and reality. For the overall torsional stiffness, the simulated value was 249 N·m/°, while the measured was 270 N·m/°, showing a discrepancy of 7.7%. The vertical stiffness value from simulation was 414 N/mm, compared to 411 N/mm from experimental measurements, with a minimal difference of -0.7%. The stiffness distribution along the length of the swingarm exhibited a correlation, but with notable variation in certain areas. This confirms that accurately simulating CFRP parts with complex geometries is highly challenging, partly due to the sensitivity of the manufacturing process. Therefore, verification through experimental measurement is considered good practice.

The article highlights the promising potential of automating the forging process to enhance the durability of multi-cavity forging tools. Entrepreneurs aim to boost production efficiency by increasing output per unit of time and reducing the degradation of forging dies and punches. The high costs associated with specialized materials and complex manufacturing processes for these tools elevate the final product price. Automation offers a viable alternative, ensuring consistent process parameters and reducing the physical strain on workers. This consistency leads to extended tool durability, even without the use of special manufacturing techniques for their production. The study simulates the durability of multi-cavity dies in automated operations, demonstrating substantial advantages compared to manual forging. Simulation programs for forging processes and tool durability offer significant cost savings by providing insights into potential fatigue cracks, aiding in decision-making, and verifying operational parameters and tool designs. These simulations reduce the need for extensive: real-world tests and modifications of the forging tools.

This article deals with the influence of the applied solution annealing temperatures in the precipita-tion hardening process on the resulting increase in the mechanical properties of Al-Si-Cu alloy cast-ings with different copper contents in the alloy. AlSi7Cu2 and AlSi7Cu4 alloys were cast by gravity casting in a metal molds. Each of the samples was subjected to the Vickers microhardness measure-ment of a solid solution of α(Al) and Brinnel hardness measurement. Microscopic analysis and evalu-ation of the internal structure of each alloy was carried out in relation to used solution-annealing temperature.

This paper carries out the simulation of abrasive flow for twist drill spiral grooves and the experimental study of abrasive flow polishing. The flow of abrasive in spiral groove in abrasive flow polishing twist drill was analyzed by CFD using FLUENT software. Different inlet speeds and abrasive concentrations were used as parameters for simulation calculations to obtain the state parameters of dynamic pressure and abrasive velocity in the flow channel, and to analyse their effects on the abrasive flow in the spiral groove. The analysis results show that the dynamic pressure in the twist drill spiral groove increases with the increase of inlet speed, and becomes smaller as the abrasive flows along the spiral surface. Under the condition of different abrasive concentrations, the velocity of abrasive decreases with the increase of abrasive concentration. Under the same abrasive concentration condition, the abrasive velocity decreases gradually from inlet to outlet. For actual processing, the abrasive concentration can be selected between 50-60%. Based on the simulation analysis results, the parameters of abrasive flow polishing process were set, the orthogonal test method was adopted, and the test data were analysed by the polar analysis method the results showed that the priority order of the influencing factors of spiral groove polishing was: abrasive type > inlet speed > polishing time. Using SiC abrasive, inlet speed 0.5 m.s^-1, polishing time30 min, the surface roughness of the spiral groove of cemented carbide twist drill after polishing is the minimum, reaching Ra0.189, which is far less than the design requirements.

Parting-off stands as a fundamental method of turning, involving the cutting of the workpiece. The tool is most frequently a replaceable insert secured in a clamping bed. A pivotal set of observable metrics that ascertain the efficacy of a tool and its appropriateness for machining a specific material under defined cutting conditions is its durability. These durability parameters need to be determined for all new tools to ensure optimal performance and application in various machining scenarios. The primary objective of this research was analysis of the wear experienced by replaceable cutting inserts within the realm of parting technology. There were three distinct variants of replaceable cutting in-serts, all produced by esteemed manufacturer Dormer Pramet s.r.o. These cutting inserts were ap-plied in the parting process, consecutively machining two materials: bearing steel 100Cr6 and stainless steel 316L. The study not only encompasses the description of the cutting test procedure but also involves the meticulous execution of measurements and the subsequent analysis of the data procured from experimental activities. In the final phase of study, additional analyses are outlined to uncover the factors contributing to variations in certain obtained results. Those analyses, such as material or tool coatings analysis, provides more information about interplay between replaceable cutting inserts and the specific materials subjected to parting processes.

The article presents results of the use ABC method applied to technological machines modernity level assessment in anti-corrosion protection of steel structures. Research findings enables identifying and analysis of the technological modernity level of machines used in the anti-corrosion protection process that is crucial for the final quality of the process and product manufactured in the steel construction production. The paper proves effectiveness of using ABC method of the machines modernity level as-sessment in the analysis and improvement of the steel construction corrosion ensuring process.

Atomic Diffusion Additive Manufacturing (ADAM) is a progressive layering process based on metallic materials with a plastic binder designed to extruse the material. The ADAM process can be classified as an indirect additive manufacturing process in which a solid fiber of metal powder enclosed in a plastic binder is applied. After creating a 3D object by the ADAM process, the excess plastic binder is removed in the cleaning chamber and vacuum sintering of the 3D object is performed. This work aims to provide a preliminary characterization of the ADAM process and compare the achieved results with the application most implemented so far in additive manufacturing for metal 3D objects using Selec-tive Laser Melting SLM. In particular, the density and microstructure of the applied process and mate-rial 17-4PH are studied, while optimal or recommended technological parameters of production facili-ties are applied. Furthermore, the dimensional accuracy of the ADAM process is observed, which is evaluated by means of IT accuracy levels according to the ISO reference artifact. Due to the applied AM process, the final character of a 3D object depends on technological parameters. The weight of a 3D object is low compared to the material processed by additive manufacturing processes in a powder bed. The dimensional accuracy and roughness of the surface depends on the geometry, orientation, and position of the individual shape specifications of the 3D object. Additive technologies generally achieve a degree of accuracy of approximately IT12 to IT13, which is comparable to traditional semi-finished metal manufacturing processes.

The Male and Cockroft ring compression test is one of the methods used to determine the coefficient of friction in forming. This method can be used to determine the coefficient of friction without the need to measure the force. This paper describes the results of the Male and Cockroft ring compres-sion test for the Hardox 450 material at different strain rates. The experiment was performed on ZD40 hydraulic press and CFA-80 pneumatic die hammer at the Faculty of Mechanical Engineering of Brno University of Technology. The test results were recorded in a calibration diagram. The results show that the strain rate has a significant effect on the coefficient of friction, specifically such that as the strain rate increases, the coefficient of friction decreases.

The impact of thermofriction on surface hardness has been investigated in this study. The metal disk method, which hardens parts' surfaces utilizing a metal disk, creates a hardened layer with the re-quired mechanical characteristics at a precise depth. The surface of treated products is one indica-tion of quality indicators. It has been noted that the thermal conductivity of the workpiece and tool material affects the irregular dispersion of heat in the processing zone. For evaluating the average integral rates of heating and cooling of the layer, the metal dependences have a significant impact on the form and properties of the friction-strengthened layer. It is discovered that several processing mode-dependent parameters affect power and density heat flow during hardening. It was found that when the feed rate increases, the hardened layer's depth decreases. The harder layer's depth increases as disk rotation speed (rpm) increases. when the disk rotation speed is increased to 265 rpm and the hardening depth (h) is 0.2 mm or less, it is said to be at N = (190-250) rpm. After heating the treated surface areas to a temperature between 130°C and 160°C above the critical temperature, the treated surface areas were then cooled applying compressed air to achieve the ideal surface hardness. After the hardening process, the surface hardness of blanks made of steel 1045 reached HRC 60, which is higher than conventional hardening.

This paper deals with the issue of selecting different machining parameters in the CAM system Siemens NX 1946. The issue of choosing between a solid end mill, milling cutter, and a high-feed tool when machining simple rectangular and rugged cavities concerning time and residual material is solved here. The chosen material was 1.1730, which is a basic material for the production of moulds without heat treatment. The paper deals with the issue of choosing the size of tool feed into the cut and its influence on the formation of the machining path depending on the depth of the cavity. The size of the residual material depends on the machining strategy and the choice of the plunge method into the material with regard to the total machining time. Performed simulations and experiments have shown a significant impact in individual settings and, thus, on the cost of machining components of such shapes.

The submitted paper deals with biotribological contact in total knee arthroplasty. The goal was to evaluate the influence of the metal component production technology on tribological parameters in defined environments. The reference sample was a standard available test ball made of the subject material, used in testing tribological properties by the "Ball on Pin" method. The preparation of the experiment consisted in the production of test disks from UHMWPE material and the production of a metal test component with a spherical surface. The condition of the experiment and the basis of this contribution is to compare the properties of conventionally produced metal material against 3D printing. Using the SLM method, a sample with a semi-spherical surface on a cylindrical shank was produced, which was subsequently ground and polished to reflect the characteristics of the standard supplied test ball. The last step was the production of a suitable fixture in order to fit the sample into the tribometer. The so-called dry friction of the heterogeneous Ti6Al4V–UHMWPE pair and the friction in a biological lubricating environment represented by bovine serum were evaluated. The evaluation of the contact surfaces took place using a profilometer and an electron microscope. The coefficient of friction was determined directly from the test device - tribometer.

The paper deals with the solubility and influence of the melting method of alloying elements (Zr, Mo and Sr) on selected properties and structure of the hypoeutectic aluminum alloy AlSi5Cu2Mg. Alloy-ing elements in the form of master alloys (AlZr20, AlMo10, and AlSr10) were melted in two different methods. The first method consisted in melting the master alloy together with the batch material in an electric resistance furnace, the second method consisted in separately melting the master alloy in an induction electric furnace and then introducing the master alloy into the molten batch. The presence of alloying elements led to an increase in the porosity in all experimental alloys, which negatively affected the resulting physical and mechanical properties.

The work deals with the possibility of using additive technology in the production of positioning and clamping device. The designed clamping device will facilitate and accelerate the measurement of samples with inclined or different irregular surfaces. The designed device is manufactured by additive technology using composites. Onyx material reinforced with Kevlar fibers was used as material for composite printing. The designed device should achieve the required properties for the firm and stable clamping of the components during the measurement process, and its weight should be significantly reduced with the use of composite material.

The propagation and velocity of the deformation wave in the thin isotropic plate is investigated. The deformation is induced by the stroke of impact body onto the facial surface of the plate. The plate is supported perpendicularly. The excitation of the plate oscillation is initialized by a unit force (Heavi-side’s jump). The impact body has a rounded facet by radius c = 2.5 mm. Hook's material model and Kirchhoff’s and Flüegge’s geometric model have been investigated. The analytical solutions for both models are presented. The MATLAB script has been assembled to solve material and geometrical mod-els. The results were compared for two selected points on the surface of the plate. Plate deformation was recorded at two points T1 (at a distance of 20 mm from the impact location on the x axis) and T2 (at a distance of 20 mm from the impact location on the y axis).

The paper focuses on proposing a method for implementing key performance indicators (KPIs) to assess the effectiveness of manufacturing processes. For the evaluated processes of precision parts machining, the share of non-conforming products was proposed as a KPI, evaluated as both an exter-nal and an internal indicator. The external indicator EXTppm expressed the quantity of faulty prod-ucts to the volume of production. Its monthly development during 2022 was evaluated. The internal KPI represented the internal share of non-conforming products INTppm during 2022 which was re-lated to the order of part A. Towards the conclusion causes for not attaining the targeted KPI values are pinpointed, and recommendations are put forth to enhance the productivity of manufacturing processes.

PolyJet technology, based on the printing and photopolymerization of model material, is currently, along with stereolithography or 3SP (Scan, Spin and Selectively Photocure), the most commonly used rapid prototyping method based on optically active resin. The article presents the results of torsional strength tests of samples made of optically active resins VeroDentPlus-MED690, VeroClear-RGD810, and Rigur-RGD450 by Stratasys in PolyJet technology. The samples were prepared in HQ (High Quality) mode with a layer height 0.016 [mm]. The tests included a static torsion test using a specialized research stand by the Department of Mechanical Engineering of the Rzeszów University of Technology. The scope of research significantly expanded the standard procedure, which complements the material data available with significant functional parameters due to the use of models. The results of the torsional strength analysis determined in the research process can be used to define the potential application area of the materials in question - optically active resins and their processing techniques for the production of parts subject to complex loads, i.e. machine shafts, clutches, and gear hubs.

This article deals with the modification of surface properties of austenitic steels using laser shock peening (LSP) technology. This technology introduces residual compressive stresses into the surface layer. These stresses improve the technical properties of the material not only by affecting the re-sistance of corrosion cracking under stress. The aim of the work was to influence the austenitic steel 08CHN10T by LSP technology, to perform a corrosion test in a boiling MgCl2 solution and the sub-sequent evaluation of these tests. Furthermore, the hardness was measured of the peened part of the material by LSP technology and unpeened part.

The quality of web products is significantly affected by the running velocity of a process line, especially during the stages of start-up and shutting down of a web processing line. At these stages, a remarkable transverse variation (web flutter) are observed due to employing improper input velocity. Web flutter may cause some web defects such as wrinkles, poor printing and even web breakage. Therefore, employing an optimal web velocity profile is crucial to minimize web transverse vibrations during the transport of the web through different processing sections in a web process line. In this paper, an optimal velocity profile along with common velocity profiles (widely used in industry) have been utilized in a running web line to demonstrate the effect of web transport velocity on transverse vibrations. Comparative experimental results are presented and discussed.

In order to accumulate experience in the design and manufacturing of the toroidal field coils for the China Fusion Engineering Test Reactor, a model coil of mixed Nb3Sn-NbTi superconducting magnet with a maximum magnetic field variation rate of 1.5 T/s has been developed at the Institute of Plasma Physics, Chinese Academy of Sciences. The preload system, as one of the key components of the model coil, plays a crucial role in maintaining the overall integrity and stability of the model coil. First the magnetic field and electromagnetic forces of the model coil under extreme conditions are calculated based on Maxwell's equations. Then, the mechanical performance of the model coil at room and cryogenic temperatures is analyzed. To addressing the issue of excessive stress in the preload components of the model coil under preload, several optimization design schemes are proposed and iteratively analyzed. Finally, stress linearization is performed, and stress evaluation is conducted based on the analytical design. The assessment results indicate that certain optimization schemes enable the preload components to fully meet the operational requirements at both room and cryogenic temperatures. The outcomes presented in the paper will provide reference for the subsequent design and manufacturing of the central solenoid coil.