Radial Fatigue Research Articles

Binary-Network structured PI@SiO2 nanofibrous composite aerogels with temperature invariant superelasticity for thermal insulation

The extreme temperatures encountered in aerospace pose formidable challenges to the performance of elastic materials in spacecraft and related apparatus. Traditional organic insulation materials face hindrance due to inadequate fire resistance, while inorganic insulation materials are often brittle. Herein, we designed binary-network composite aerogels with dual-crosslinked PI nanofibers as the scaffold and uniformly distributed silica nanoparticles within the anisotropic aerogel matrix. Owing to the dual-crosslinked PI nanofiber network, the resulting PI@SiO2 aerogel can withstand 1000 cycles of radial fatigue testing under 50 % compressive or buckling strains, maintaining structural stability across a wide angular frequency range of 0.1–100 rad/s. DMA testing shows that PI@SiO2 aerogel can endure 100,000 fatigue cycles from 25 to 300 °C, with storage modulus and loss modulus, and damping ratio, indicating robust long-term performance over a wide temperature spectrum. Even with liquid nitrogen (−196 °C) and butane torch flames (1100 °C), PI@SiO2 aerogel preserves its superelasticity through repeated compressions. Moreover, the composite aerogel exhibits excellent thermal insulation, with low thermal conductivity (27.2 mW m−1 K−1), and reachs the top flame-retardant level (UL94-V0). This work not only establishes a novel pathway for constructing polymer-based materials with temperature-invariant superelasticity but also holds great promise for extensive applications in ongoing and near-future aerospace exploration.

Mechanical Behavior of Polymer Braided Stent at Rapid Radial Loading

Stent implantation is the mainstream treatment for high-incidence vascular diseases. The stent is implanted into the blocked vessel with minimal trauma to restore blood flow. Polymer braided stents with superior biocompatibility and flexibility have broad application prospects in stent implantation. An ideal polymer stent should have suitable radial supporting capacity to withstand the cyclic radial load from vessels. Especially in the case of accelerated vasoconstriction caused by emotional excitement, drinking or fever, etc. However, there are currently limited studies on the mechanical properties of stent at rapid radial loading. In this work, the radial supporting capacity and fatigue properties of polymer stent at rapid loading rate were investigated by experiment and simulation. With the increase of radial loading rate, the stent has different deformation tendency and fatigue resistance. This study is helpful to study the structural changes of the polymer braided stent at different loading rates, and provide ideas for the evaluation and the optimization of the polymer braided stent.

Enhancing Steel Wheel Ventilation Efficiency Through Multi-Objective Optimization

This study focuses on the optimization of ventilation hole design in steel wheels used for heavy commercial vehicles. The primary objective is to reduce the weight of the wheel while ensuring compliance with radial fatigue and cornering fatigue test requirements. Four distinct ventilation types were parametrized using ANSYS Mechanical, with the von Mises stress on the disk, number of ventilations, and wheel weight serving as design parameters. Stress analysis and weight comparisons were performed between wheels featuring different ventilation types and an ellipse ventilation wheel. Incorporating the design of experiment (DoE) and response surface optimization (RSO) module in ANSYS Workbench 2022 R1 was employed to compare and evaluate the obtained values. Subsequently, the multi-objective genetic algorithm (MOGA-II) method was employed for optimization, aiming to identify the optimal design. The optimization process, utilizing a maximum of 20 iterations, a convergence stability percentage of 2%, and a maximum allowable Pareto percentage of 70%, yielded 1, 3, 3, and 3 candidate design points for round, slot, trapezoid, and halfmoon-type ventilation holes, respectively. Among the various ventilation types considered, the halfmoon-type ventilation hole exhibited the most promising results. Compared to the current design, the optimized wheel achieved a weight reduction of 0.9 kg (2.05%). This outcome demonstrates the effectiveness of the proposed methodology. Although lighter designs were not attainable while maintaining the same stress values for the other three ventilation types, the halfmoon-type ventilation hole was ultimately selected as the preferred design.

Topology optimization of wheel spoke under fatigue tests considering the rotation characteristics of automobile wheels

The topology structure of wheel spoke has a great impact on the safety and lightweight of automobile wheels. However, the rotation process of the wheels is difficult to be reflected in the design and optimization. In this paper, the topology optimization of wheel spoke under fatigue tests considering the rotation characteristics is studied. The bending fatigue test and radial fatigue test are first introduced and the corresponding computation models are presented to calculate the mechanical performances of the wheel hub. The relationship between the internal stress and the number of the wheel spokes is established, and the mechanical performances with different number of wheel spokes are analyzed to guide the selection to the number. Then, the rotation characteristics of the wheel hub are simplified as static loads at different directions or positions according to the configuration of the wheel spokes. A comprehensive evaluation function which includes the test and load levels is defined by the compromise programming method to simulate the stress during the rotation process. Two levels of topology optimization methods are determined. Next, a mathematical model of multi-objective topology optimization for the wheel spoke is established based on the Solid Isotropic Material with Penalization, and a new wheel hub is obtained. Finally, the mechanical performances are compared with the original wheel hub. The obtained results show that the stiffness and strength of the wheel hub are improved under two test conditions, while the weight is reduced by 2.75%.

An automotive steel wheel digital twin for failure identification under accelerated fatigue tests

In this paper, a digital twin to predict failure in automotive steel wheels during experimental fatigue tests is proposed. The methodology involves a wheel finite element model that incorporates assembling and mounting processes, and CDTire/3D simulation package, employed to calculate tyre to rim generalised internal forces in several loading conditions. The two models are decoupled under small deformation assumption, which allows to reduce computational effort for batch simulations. The Digital Twin (DT) is designed to meet the standard requirements and the working principles of test benches for dynamic cornering, radial, and biaxial fatigue tests. The overall DT architecture is described with emphasis on different test bench logic and the introduction of simplifications to efficiently estimate failure under mean stress variation. Then, a simplified formulation of the critical plane McDiarmid multi-axial failure criterion is presented to face the non-proportionality of stress path under loading conditions. Finally, the methodology is validated against an industrial case study: the predicted failures are compared to experimental test result database for wheel topologies, material properties, test benches and loading conditions.

Fatigue life optimization and lightweight design of wheel based on entropy weight grey relation analysis and modified NSGA-II

In order to study the fatigue performance of wheel and enhance its lightweight design level, this article proposes the structure, design and optimization method of magnesium-aluminum alloy assembled wheel. Taking a [Formula: see text] type wheel as the research object, the optimal topology of wheel spoke is solved by constructing a topology optimization model for wheel bending and radial fatigue test conditions. A finite element model for bending and radial fatigue testing of assembled wheels was established, which simulates and analyzes the fatigue performance and its influencing factors of the wheel under two working conditions. Combined with contribution analysis method, the modified NSGA-II and entropy weight grey relation analysis (EGRA), the multi-objective optimization of assembled wheel was performed. The result demonstrated that the weight reduction of the assembled wheel after optimized design is 4.49%, while the bending fatigue life and radial fatigue safety factor are decreased by 9.95% and 25%, respectively. In order to better balance the performance of assembled wheel and achieve lightweight design, this article combines the joint topology optimization of assembled wheels with multi-objective optimization method for multiple working conditions and screens the optimal compromise solution by EGRA, which provides an approach for wheel lightweight design and multi-objective optimization.

A Novel Metamaterial-Based Stent with Dual Properties of Auxetic and Self-Expanding

Vascular stents have been widely used in various cardiovascular diseases associated with atherosclerosis, while the potential risks of in-stent restenosis (ISR) and stent thrombosis (ST) still restrict its further development. Here, by combining the self-expanding (SE) mechanism and auxetic metamaterial, a novel SE stent called MBS was proposed and systematically studied. Through the finite element (FE) method, a stent-artery coupling model was established to study the crimping, expanding, and pulsating behaviors of the proposed MBS. Results show that the MBS well retains various advantages, including a large recoverable strain, a large radial resistance force (RRF), and a smaller radial opening force (ROF). Meanwhile, due to the auxetic effect of the adopted re-entrant honeycomb, the MBS shows a significant negative foreshortening behavior, which can be designed from about -5% to about -50%. Besides, fatigue analysis also shows that all strain-based points are within the design criteria. Geometric parameter of RE cell shows a great effect on the comprehensive performance of the MBS, which needs a further optimal design for ideal radial force, foreshortening effect and fatigue performance. In conclusion, the novel design is expected to improve the mechanical properties of the traditional stent, which should be given more attention in further research.

Study on fatigue fracture of SW400 fine-grained high-strength steel T-lap joint

The SW400 fine-grained high-strength steel T-lap joints were welded by submerged arc welding. The influence of welding technology on the geometrical characteristics of welds and fatigue performance of the joints were studied by radial fatigue test with different welding parameters. The numerical analysis was used to study the characteristics of the stress distribution. And the fatigue fracture morphology was analyzed by scanning electron microscope. The results show that with the increase of welding line energy, the thickness of the weld increased, and the propagation direction of the fatigue crack changed from the weld to the base metal. When the thickness was less than 4 mm, the high-stress region was in the area of the weld around the weld root, and the fatigue crack propagated to the weld. When the thickness was greater than 4.5 mm, the high-stress region of AE and AS were in the weld around the root, where the crack propagated to the weld, while in the middle of the weld high-stress region was in the area of base metal around the weld root, crack propagated to the base metal. With the increase in the thickness of the weld, the maximum mises stress decreased, and the crack propagation rate decreased. The time of crack initiation was very short, which occurred in the high-stress region of the weld root in the middle of the weld.

Aftermarket Wheels Numerical Simulation To Get Maximum Stress and Deformation Values

The purpose of this research is to get wheels with offset variants of -15, +20, and +35 made of aluminum alloy with a maximum load of 690 kg. Autocad 2018 and Unigraphic NX 8 were used to create all three designs. The load was calculated using the SAE J2530 standard and simulated using the ANSYS Workbench 14.5 application's numerical simulation method. As a result, the car rim is designed with a spoke form that becomes steeper (Concave) as the offset decreases. Methods a) Dynamic Cornering Fatigue Test, b) Dynamic Radial Fatigue Test, and c) Impact test consecutively at offset -15 of a) 62.33 MPa, b) 111.61 MPa, and c) 1.58 mm can be used to obtain numerical simulation results. For offsets of +20 of 70.91 MPa, 75.75 MPa, and 1.6 mm. And a) 90.33 MPa, b) 78.13 MPa, c) 1.61 mm at offset +35.

Shape optimization method for wheel rim of automobile wheels based on load path analysis

The wheel rim is an annular and thin-walled structure with complex structural features and working conditions. Guaranteeing its safety and lightweight are two major concerns in wheel rim design. In this study, a shape optimization method based on load path analysis is proposed to evaluate and optimize the structure of the wheel rim. The load-transfer law of the wheel rim is identified based on the load path visualization. Two design criteria are put forward to evaluate the load-bearing performance and give the improvement suggestions. Then, the shape optimization problem is simplified to a parameter optimization problem, and the optimal size combination performance-oriented is obtained using the non-dominated sorting genetic algorithm II (NSGA-II). As a case study, a wheel rim is redesigned and the optimization result shows that the stiffness and strength are improved under bending and radial fatigue simulation, while the weight is reduced by 3.78%. Two stages of experimental studies are carried out to verify the optimization method. The static pressure test shows that the bending resistance performance of the wheel rim is improved by 4.57%, and the load transfer is more uniform. The radial impact test shows that the impact deformation at a high energy level is reduced by 13.77%, indicating that the impact resistance performance is significantly improved.

Fatigue/impact analysis and structure–connection–performance integration multi-objective optimization of a bolted carbon fiber reinforced polymer/aluminum assembled wheel

This study aimed to provide a multi-material lightweight solution for wheels. A carbon fiber reinforced polymer (CFRP) rim structure was designed, and a finite element model of the bolted CFRP/aluminum assembled wheel was established. The bending and radial fatigue strengths and the 13° and 90° impact performance of the bolted assembled wheel were analyzed. Then, a structure–connection–performance integration multi-objective optimization was conducted with the fatigue and impact performance as objectives and the structure, connection, and lay-up parameters as design variables. The optimized assembled wheel was fabricated and tested, and results showed that its fatigue and impact performance met the standard requirements.

Forecasting technical performance and cost estimation of designed rim wheels based on variations of geometrical parameters

Abstract Rim wheel testing through the SAE standard is necessary for driving safety. This study focused on rim wheel tests carried out using the dynamic radial fatigue test method, which has been included in the SAE standard using Fusion360 for the design and ANSYS for the simulation. With different parameters for the rim wheel type, only some parameters of the tested rim wheels were able to pass the standardization by SAE; 16 rim wheels passed the test, while the other 11 rim wheels did not pass. Simulation results suggested that variations in the thickness, geometry, and material affected the displacement of the safety factor, which was inversely proportional. In addition, the variation in the rim wheel produced a change in the safety factor due to changes in its mass and cost, which were directly proportional. The results of this study will aid in rim wheel design, not only in terms of achieving the best performance but also with regard to cost efficiency.

Effect of design and material on structural rigidity of automobile wheel - an optimisation approach

An automobile wheel plays a vital role in supporting the tyre and the entire weight of any vehicle. This study aims to examine the distribution of stress and deformation across 5-twin-spoke and multi-spoke wheel designs whilst varying lightweight materials, as well as optimise the base designs of the wheel such that they reach an optimum level. The wheel was modelled using SolidWorks, before being analyse by Finite Element Analysis software whereby aluminium and magnesium alloys were assigned. The structural rigidity of the wheel models was assessed by conducting static structural analysis and radial fatigue analysis. Changes in terms of total deformation, von-Mises and alternative stress were obtained, and tabulated. Optimisation of the wheel models was conducted by making necessary modifications to the base designs. The result shows that multi-spoke fared better than 5-twin-spoke in both analyses, and the notable weak point observed is the hub region. In term of material-wise, it was found that Magnesium AZ91D alloy generally has higher deformation, von-Mises and alternating stress than Aluminium 6061 Alloy. Future works could be focused more on conducting additional tests so that the wheel models are well-geared for road usage, such as impact and cornering fatigue tests.

A systematic approach to further improve stent-graft performance

Thoracic endovascular aortic repair (TEVAR) is limited by the complicated anatomy of an aortic arch. This study proposed a new stent-graft (SG) design with slits that can positively improve the sealing effect between the aorta and SG while maintaining blood flow to supra-aortic branches. Firstly, a new SG was designed by changing the geometrical parameters (strut height, strut radius, strut diameter, etc.) based on previous research. The main mechanical performances of the SG were evaluated. Results showed that the new design improved the sealing effect and decreased the Type-Ι endoleak risk. The new design also had the comparable radial force, compression strength and fatigue life. Secondly, a fluid dynamic analysis was carried out in an ideal normal aortic arch model to evaluate the slit SG design. Satisfactory flow perfusion in branches was obtained, and no undesirable vortexes were found. Therefore, the hemodynamic environment in the aortic arch after the SG implantation was not significantly changed. The present study indicates that the design thought has a potential to deal with the technical difficulties of TEVAR at the aortic arch. This study provides the basis for potential optimization to obtain a more applicable SG design.

Design and Analysis of Alloy Wheel

Importance of wheel in the automobile is obvious. The vehicle (car) may be towed without the engine but at the same time even that is not possible with out the wheels, the wheels along the tyre has to carry the vehicle load provide cushioning effect and cope steering control. The main requirement of automobile wheel it must be strong and perform all operations above functions. It should be balanced both statically as well as dynamically. It should be lightest possible so that the unsprung weight is least. The wheel has to pass three types of test before going production, they are cornering fatigue test. Radial fatigue test and Impact test. In this thesis radial fatigue analysis is done to find the number of cycles at which the wheel is going to fail. The wheel is meshed using SOLID 45 element. A load of 2500N was applied on the hub area of the wheel and a pressure of 0.207N/mm2 is applied on the surface of rim.

Effect of geometrical irregularities on fatigue of lead sheathing for submarine high voltage power cable applications

High voltage subsea power cables are typically composed of several layers, including: a conductive core, a dielectric layer, a ductile metallic watertight barrier and a series of radial and axial armours and polymer layers. The watertight barrier serves the purpose of preventing water permeating to the dielectric due to the outer layers' polymer hygroscopicity. Water impregnation may cause dielectric breakdown, with fatal consequences on the integrity of the power cable. The watertight barrier is made of extruded lead alloy and is subjected, during the installation and operational life of the component, to axial and radial displacement-controlled fatigue which might lead to cracking, thus to a loss of its isolating properties. Lead, due to the low melting temperature, is characterized by creep deformation and damage even at room temperature. A steel tape is winded around the polyethylene sheathing surrounding the lead barrier, which is deformed, and a helical ridge is generated. This irregularity causes a local concentration of strain which might potentially lead to early failure of the lead sheathing. In this work the results of displacement-controlled fatigue testing at different strain rates of sheathing material including the irregularity is presented and compared to the results in equivalent conditions, but in the absence of the irregularity. The strain concentration caused by the defect is analysed with the implementation of a creep material model calibrated on the cyclic properties of the alloy and the notch sensitivity of the material for the class of defects, temperature and frequency in exam is obtained. The results are applied to the modelling of the stress-strain field in the component with and without irregularity and conclusions are drawn on the danger that such irregularities pose on the structural integrity on the power cable.

Radial Fatigue Analysis of Automotive Wheel Rim(ISO 3006)

Due to many unexpected harsh environmental conditions of the road, automotive wheel is a vital part to ensure the vehicle safety and performance. ISO-3006 provides a comprehensive fatigue life experiment to validate proper wheels. This article is investigating a car wheel under the dynamic radial fatigue test of the ISO standard. This study aims to compare five different commercially available materials of the wheel concerning the ISO test conditions. As the wheel rim weight has a great impact on the performance of the vehicle, this comparison is considering the weight of the wheel made of various materials. The test is simulated via ANSYS software with a dens mesh to ensure the highest possible accuracy of results. Among selected materials, the CFRP is demonstrating the best fatigue strength to weight ratio in ISO radial fatigue test.

Radial Fatigue Analysis of Automotive Wheel Rim(ISO 3006)

Due to many unexpected harsh environmental conditions of the road, automotive wheel is a vital part to ensure the vehicle safety and performance. ISO-3006 provides a comprehensive fatigue life experiment to validate proper wheels. This article is investigating a car wheel under the dynamic radial fatigue test of the ISO standard. This study aims to compare five different commercially available materials of the wheel concerning the ISO test conditions. As the wheel rim weight has a great impact on the performance of the vehicle, this comparison is considering the weight of the wheel made of various materials. The test is simulated via ANSYS software with a dens mesh to ensure the highest possible accuracy of results. Among selected materials, the CFRP is demonstrating the best fatigue strength to weight ratio in ISO radial fatigue test.

Design and optimization of tapered carbon‐fiber‐reinforced polymer rim for carbon/aluminum assembled wheel

AbstractA multi‐objective integrated optimization framework that considers the manufacturing process in the design of a tapered carbon‐fiber‐reinforced polymer (CFRP) rim structure was established. Firstly, the three‐zone symmetrically stacked CFRP rim structure was proposed and modeled. The bending and radial fatigue and 13° impact of the carbon/aluminum‐assembled wheel composed of CFRP rim and aluminum alloy spoke were analysed. Coupling lay‐up thickness, sequence and angle as design variables, multi‐objective integrated optimization design for the tapered CFRP rim structure was performed through radial basis function neural network surrogate model combined with an elitist non‐dominated sorting genetic algorithm approach. Pareto‐optimal solutions were obtained, and the trade‐off solution was selected through grey relational analysis coupled with entropy weighting method. Finally, the tapered CFRP rim was manufactured through molding and autoclave forming technology. The CFRP rim has a weight saving of 17.2% compared with the previously developed forged magnesium alloy rim of the same size. The bending and radial fatigue and 13° impact performance of the assembled wheel were then validated by corresponding physical test, results of which met GB 36581‐2018 standard.

Numerical prediction of fatigue life of an A356-T6 alloy wheel considering the influence of casting defect and mean stress

A fatigue prediction method considering shrinkage cavity, secondary dendrite arm spacing (SDAS) and mean stress level is presented in the paper. Firstly, the casting process of an aluminum alloy wheel is simulated based on ProCAST software. And the data of SDAS and porosity of different parts are predicted based on the solidification process. Then the data mapping algorithm between tetrahedral mesh elements is developed to realize the unidirectional transformation of microcosmic data from a cast model to a static mechanical model. And the radial loading mechanical analysis model of a wheel containing microcosmic information is further established. According to the specific mechanical and fatigue parameters of each node, the fatigue life prediction model is established by Fesafe software. Based on the self-developed Transfer Couple Data (TCD) software, the integrated coupling method of the three software prediction models is realized, and the method is further used to realize a precise prediction of the radial fatigue life of a wheel considering effects of shrinkage cavity, SDAS and mean stress. Compared with the experimental results, after considering the microcosmic influence, the predicted position of the minimum life is unchanged, and the predicted life value is more accurate after considering the microcosmic influence. The proposed method lays a solid foundation of the optimization design and lightweight design of aluminum alloy wheels.