Optimal Suspension Research Articles

Multi-Objective Optimisation of Tyre and Suspension Parameters during Cornering for Different Road Roughness Profiles

Effective emission control technologies and novel propulsion systems have been developed for road vehicles, decreasing exhaust particle emissions. However, work has to be done on non-exhaust traffic related sources such as tyre–road interaction and tyre wear. Given that both are inevitable in road vehicles, efforts for assessing and minimising tyre wear should be considered. The amount of tyre wear is because of internal (tyre structure, manufacturing, etc.) and external (suspension configuration, speed, road surface, etc.) factors. In this work, the emphasis is on the optimisation of such parameters for minimising tyre wear, but also enhancing occupant’s comfort and improving vehicle handling. In addition to the search for the optimum parameters, the optimisation is also used as a tool to identify and highlight potential trade-offs between the objectives and the various design parameters. Hence, initially, the tyre design (based on some chosen tyre parameters) is optimised with regards to the above-mentioned objectives, for a vehicle while cornering over both Class A and B road roughness profiles. Afterwards, an optimal solution is sought between the Pareto alternatives provided by the two road cases, in order for the tyre wear levels to be less affected under different road profiles. Therefore, it is required that the tyre parameters are as close possible and that they provide similar tyre wear in both road cases. Then, the identified tyre design is adopted and the optimum suspension design is sought for the two road cases for both passive and semi-active suspension types. From the results, significant conclusions regarding how tyre wear behaves with regards to passenger comfort and vehicle handling are extracted, while the results illustrate where the optimum suspension and tyre parameters have converged trying to compromise among the above objectives under different road types and how suspension types, passive and semi-active, could compromise among all of them more optimally.

Constraint optimization of nonlinear McPherson suspension system using genetic algorithm and ADAMS software

In this article, optimization of the McPherson suspension mechanism of a real car named Arisan is considered. In this regard, a model based on a real-life suspension system is proposed with the least simplification. This model is built in the ADAMS/View software based on the actual size of the suspension mechanism of Arisan. Moreover, the user-written code of the genetic algorithm in C is added as a plug-in to the ADAMS/View software in a completely innovative way to optimize the suspension system. 16 parameters of the suspension system are selected as design variables to wholly handle its geometry. The value of all design variables is optimally found by GA to minimize the variation of the camber angle as an objective function. Comparison of the obtained optimum suspension by the proposed method with the actual suspension system of Arisan shows a 23.5% improvement in the camber variation angle. It is worth noting that the proposed method does not require a mathematical model of the suspension system that leads to some simplifications such as linearization and non-friction joints. The proposed method can be used for modeling and optimization of other nonlinear dynamical systems such as robotics and building structures.

Cooperative control of yaw and roll motion for in-wheel motor vehicle with semi-active suspension

A new vehicle motion control strategy is proposed, which synthesizes the rolling and yaw performance of vehicle by cooperating the damping force of semi-active suspension and yaw moment. To address the coupled dynamic behavior of roll and yaw motion, the modeling approach for nonlinear roll and yaw coupled dynamics is firstly employed. Furthermore, considering that the yaw and roll controllers are located in different electronic control units in practice, a distributed structure of cooperative control is presented. The key of cooperative control is that the damping force of semi-active suspension is controlled to adjust the roll dynamic, the front- and rear-axle load transfer cooperating the yaw motion; the yaw stability controller is designed to improve the yaw dynamic performance. To design the suspension damping force controller, the effect of the suspension damping force on roll and yaw dynamic behavior is discussed, and the piecewise-linear damping-force model with drive current as input is established. Moreover, the optimal suspension drive current is designed to alter roll performance and load transfer. To enhance the yaw dynamic performance, the yaw stability controller based on a sliding mode method is explored, and the optimal sliding-surface parameter is discussed to synthesize the settling time and overshoot of the yaw rate. Simulation and hardware-in-loop (HIL) test results show that the cooperative control combines the roll and yaw dynamics performance well; the overshoot and oscillation of yaw rate and lateral speed can be restrained.

Nano-Al doped-MoO3 high-energy composite films with excellent hydrophobicity and thermal stability

Developing the thermal stability of metal-based ceramic composites or their films has always been challenging and bottlenecks for the utilization of energy. In this paper, the novel mesh-like functional Al doped-MoO3 nanocomposite film with even distribution and high purity was firstly fabricated by the high-efficiency electrophoretic deposition and surface modification. The optimal suspension turned out to be the mixture of isopropanol and the additives of polyethyleneimine and benzoic acid. The microtopography, crystalline structure, environmental resistance and thermal stability were analyzed by field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX), X-ray diffractometer (XRD), exposure and droplet-impacting test, DSC analysis and ignition test, respectively. The water contact angle and sliding angle of product can reach ~170° and <1°, indicating the excellent anti-wetting property. In addition, the high heat-release (~3180 J/g) of product all kept almost unchangeable after six months exposure experiments, demonstrating the outstanding thermostability. The exquisite design idea here can perfectly match microelectromechanical system (MEMS), providing the valuable reference for fabricating other metal-based high-energy composites with long lifespan for real industrial applications.

Game-Based Multiobjective Optimization of Suspension System for In-Wheel Motor Drive Electric Vehicle

Since the driving motor is embedded in the wheel, the unsprung mass and the wheel rotational inertia of the in-wheel motor drive electric vehicle both increase, which not only affect the vehicle smoothness but also worsen the motor’s working condition due to its own vertical vibration. The evaluation index of in-wheel motor’s vertical vibration is introduced on the basis of vehicle smoothness analysis. The parameters’ optimization of vibration absorber and suspension are carried out, respectively, and the optimization results show the contradictory relationship between smoothness objective and the motor’s vertical vibration acceleration objective. Regarding the contradictory indices of the smoothness and the motor’s vertical acceleration as the objective function, a multiobjective optimization scheme is designed. Then, the orthogonal experimentation and fuzzy clustering method are applied in the multiobjective optimized design based on the game decision analysis, and the Nash equilibrium and cooperative competition game theory are used to optimize the parameters of suspension and vibration absorber. The optimized results verify the game relation between the optimization variables, the game optimization obtains better optimized results than traditional linear weight sum method, and the in-wheel motor functional stability and the vehicle smoothness can be both achieved. Compared with the traditional complex iterative process and the manmade preassurance weight allocation, the game optimization has the advantages of less iterations, faster convergence, and less influence by human experience.

Energy Saving Design and Optimization of suspension System in Baja Competition for College Students

The suspension design and optimization of Baja car were carried out on the premise of meeting the rules of the race in order to improve the handling stability and ride smoothness of the car. Firstly established the 3 d modelling software UG in suspension system 3 d model, the according to the design of the frame model of hard point ADAMS motion simulation model of motion simulation analysis and optimization selection of parameters, stress suspension system was analyzed by ANSYS, ensure the strength of the car, according to the four-wheel positioning parameters of suspension system and, along with the change of wheel parallel to beat curve using ADAMS/Insight module for parametric curves were optimized. Combined with the design and optimization, the front wheel camber angle changed from 0.81 to 0.68, the caster angle changed from 5.66 to 5.84, the caster angle changed from 6.35 to 6.42, and the front wheel toe angle changed from-1.48 to 0.99, jumping up and down in front wheel track changes reduced from 100 mm to 50 mm, swing arm to connect hard point rise of the front suspension arm Angle smaller, ultimately achieve steering the car light, effectively improve the performance of the car.

Enhanced photocatalytic decomposition of NO on portland cement concrete pavement using nano-TiO2 suspension

Photocatalyst titanium dioxide (TiO2) has been widely applied on asphalt and concrete pavements to mitigate the air pollution caused by traffic exhaust. In general, most of the TiO2 used in previous studies was pure anatase, which only exhibited excellent photocatalytic activity under ultraviolet (UV) light. Thus, N-doping method was selected to improve the photocatalytic activity, especially under visible light. Additionally, the TiO2 suspension was commonly used on the pavements comparing with other application methods. However, the Nano-TiO2 particles with great surface area-to-volume ratio and surface energy have a strong tendency to agglomerate in the suspension, which has significantly negative effects on the photocatalytic activity. Thus, the objective of this study was to enhance the photocatalytic performance of mortar specimens containing TiO2 by preparing optimum N-doped TiO2 and suspensions using both single-factor and orthogonal experimental design. Methylene blue (MB) decomposition results indicated that the optimum N-doped TiO2 was prepared with 1% N-dosage at 700 °C for 5 h. X-ray diffractometer (XRD) pattern results implied that the phase transformation from anatase to rutile occurred around 700–800 °C and anatase transferred to rutile completely at 900 °C. Absorbance results showed that the optimum suspension was prepared with following conditions: ultrasonic power 100 W, ultrasonic time 120 min, silica sol concentration 0.5%, and sodium hexametaphosphate (SHMP) dosage of 0.3%. Lastly, NO decomposition test was conducted to investigate the effects of TiO2 implementation methods and environmental factors on the photocatalytic performance of mortar specimens. The NO decomposition results showed that the optimum suspension could significantly improve the photocatalytic performance of specimens. Meanwhile, the NO decomposition percentage decreased with the increasing flow rate and NO concentration.

Design Optimization of Suspension System used in Heavy Load Vehicle

Design Optimization of Suspension System used in Heavy Load Vehicle

РЕЗУЛЬТАТЫ ДВУХФАКТОРНОЙ ОПТИМИЗАЦИИ ПАРАМЕТРОВ ПЕРСПЕКИВНОЙ МОДУЛЬНОЙ КОНСТРУКЦИИ ГИДРОПНЕВМАТИЧЕСКОЙ ПОДВЕСКИ ЛЕСОВОЗНОГО АВТОМОБИЛЬНОГО ТРАНСПОРТА

The necessity to reduce the cost of timber haulage by logging road transport to increase the efficiency of logging in the Russian Federation has been substantiated. The drawbacks of the timber road transport equipped with traditional suspension systems, which are manifested when they transport timber along low quality logging roads, have been revealed. A promising direction for improving the operational properties of timber road transport used for hauling timber is described. It consists in the development of effective design schemes for suspensions for timber road transport with optimal suspension parameters. The scientific works of foreign scientists in this direction has been considered. Taking into account the identified shortcomings, a promising scheme of modular hydropneumatic suspension for timber road transport has been developed, which makes it possible to recuperate the energy of the working fluid when moving on the roads of low quality, compensate for leaks of working fluid, and also control the ground clearance from the driver's cab remotely. Two-factor optimization has been carried out, which allows identifying favorable combinations of the two factors under study. The graphs of the influence of the pneumatic cylinder diameter heat transfer coefficient on the maximum vertical acceleration of the sprung mass, as well as on the maximum gas pressure in the pneumatic cylinder and the amplitude of the temperature change have been obtained. The cartograms of optimization of the design parameters for perspective hydropneumatic suspension have been presented.

Control of Electric Wheelchair Suspension System based on Biodynamic Response of Seated Human Body

Electric wheelchair is one of the equipment to be used by the incapacitated and disable people. Constant exposure to vibration affects human comfort and health. Reducing the vibrations transmitted to the human body is important in the electric wheelchair design and becomes a healthcare industry demand. This paper deals with the study on vibration control of the electric wheelchair suspension system. A generalized model of the electric wheelchair suspension, including the biodynamic model of seated human body is presented. In order to achieve optimal suspension performance, an active control for wheelchair suspension is designed based on H-infinity control criterion. Numerical simulations are carried out to demonstrate the effectiveness of the proposed wheelchair suspension system. The simulation results show that the proposed control system can effectively attenuate the vibration amplitude and improve the wheelchair suspension performance. This control system could be used for electric wheelchair design and assist with improving human comfort.

Facilely controllable synthesis of multi-functional aluminum/nickel/perfluorosilane composites for enhancing the thermal energy release stability and enhancing anti-wetting properties

This study firstly proposed the fabrication and characterization of novel multifunctional aluminum/nickel/perfluorosilane composites with stable thermal energy release capability and anti-wetting properties via a controllable electrophoretic assembly deposition (EAD) method through co-assembly of aluminum and nickel nanoparticles and further surface functionalization with natural drying. Products exhibited promising reticulate-like microstructures with uniform distribution and high degree of crystallinity. The controllable fabrication of composites can be realized conveniently by deeply analyzing the assembly dynamics of EAD process of different nanoparticles in an optimal suspension (Visopropyl alcohol:Vpolyethyleneimine:Vperhydrobisphenol A = 50:1:1.5). The differential scanning calorimetry (DSC) results demonstrated a violent energy release (Q = 3.12 × 105J/kg) of composite that confirmed by the ignition tests, and the corresponding output of heat (Q) kept stable with low fluctuation degrees (Fd = ~2%) in different real environments. Moreover, products turned out to possess outstanding anti-wetting properties for various droplets with different surface tensions under changeable environments (e.g. hydrogen, oxygen, humidity, etc.) after extra-long (2 years) exposure experiments, and their contact angle still exceeded 150° even for hexadecane with a low surface tension of 27.5 mN/m. Over all, the feasibility of the concept for designing multifunctional aluminum/nickel/perfluorosilane composites demonstrated in this study has great potentials to be generally applied to facilitate the efficient design of a myriad of metal(s)@polymers composites with wide applications.

An Effective Method for Hybrid CNT/GNP Dispersion and Its Effects on the Mechanical, Microstructural, Thermal, and Electrical Properties of Multifunctional Cementitious Composites

This paper reports a study undertaken to achieve a compatible and affordable technique for the high-quality dispersion of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) in an aqueous suspension to be used in multifunctional cementitious composites. In this research work, two noncovalent surfactants with different dispersion mechanisms (Pluronic F-127 (nonionic) and sodium dodecylbenzene sulfonate (SDBS) (ionic)) were used. We evaluated the influences of various factors on the dispersion quality, such as the surfactant concentration, sonication time, and temperature using UV-visible spectroscopy, optical microscopic image analysis, zeta potentials, and particle size measurement. The effect of tributyl phosphate (TBP) used as an antifoam agent was also evaluated. The optimum suspensions of each surfactant were used to produce cementitious composites, and their mechanical, microstructural, electrical, and thermal behaviors were assessed and analyzed. The best dispersed CNT+GNP aqueous suspensions using Pluronic and SDBS were obtained for concentrations of 10% and 5%, respectively, with 3 hours of sonication, at 40°C, with TBP used for both surfactants. The results also demonstrate that cementitious composites reinforced with CNT+GNP/Pluronic showed better mechanical performance and microstructural characteristics due to the higher quality of the dispersion and the increasing hydration rate. Composites prepared with an SDBS suspension demonstrated lower electrical and thermal conductivities compared to those of the Pluronic suspension due to changes in the intrinsic properties of CNTs and GNPs by the SDBS dispersion mechanism.

Development of an appropriate simple suspension method for valganciclovir medication

BackgroundValganciclovir (VGC) is essential for preventing cytomegalovirus infections after transplants in adult and pediatric patients. In pediatric patients, VGC tablets have to be pulverized so that they can be delivered via nasogastric tubes. The “simple suspension method” is usually used to suspend tablets in hot water in Japan. However, the optimal suspension conditions and metering methods for preparing VGC suspensions using the simple suspension method are unclear. The purpose of this study was to clarify these issues.MethodsVGC tablets were suspended in water (initial water temperature: 25 °C or 55 °C) using the simple suspension method. The residual rate of VGC after it had been suspended in hot water was determined using HPLC. In addition, the suspended solution was passed through 6, 8, and 12 Fr. gavage tubes. The VGC concentrations of suspensions produced using different preparation methods were also determined using HPLC.ResultsCracking the surfaces of VGC tablets and suspending them in water at an initial temperature of 55 °C was effective at dissolving the tablets. The VGC concentration of the suspension remained stable for at least 80 min. Furthermore, the VGC concentration remained stable for 48 h during cold dark storage. Cracking the surfaces of VGC tablets could be a more effective metering method than preparing powder from VGC tablets. In addition, little VGC remained in 6, 8, or 12 Fr. gavage tubes after VGC solution was passed through them.ConclusionThe amount of VGC should be measured carefully when preparing VGC solutions using the simple suspension method.

Physicochemical stability of colloidal systems using the cape gooseberry, strawberry, and blackberry for spray drying

Tropical fruits have organoleptic and nutritional characteristics that are desired by consumers. The cape gooseberry (CG), strawberry (S), and blackberry concentrate (BC) contain a large number of bioactive compounds. The aim of this research was to determine the influence that a composition of a suspension based on CG, S, and gum arabic (GA) had the stability of a colloidal system. The emulsion was homogenized. A central composite experimental design was used and the independent variables were: % of cape gooseberry solids (STC) (50%–62%), strawberry solids (STS) (18%–24%), and gum arabic solids (STGA) (0.4%–0.6%). The dependent variables were viscosity (μ), zeta potential (ζ), particle size (D10, D50, D90), total solids (STCS), spectral stability index (R), and antioxidant activity (ABTS and DPPH). The suspension was experimentally optimized with the following results: STC:50%, STS:18.9%, STGA:0.6%, μ:485.27 ± 8.46, |ζ|:20.03 ± 1.04, D10:14.41 ± 1.61, D50:165.20 ± 3.36, D90:428.52 ± 17.53, STCS:11.20 ± 0.18, R:0.22 ± 0.03, ABTS:1,307.41 ± 18.71, and DPPH:1632.56 ± 73.19. Experimental validation of the optimal suspension formulation conditions showed good results, which meant that a stable suspension was obtained with high antioxidant activity. Practical applications The following research establishes the optimal formulation of a suspension based on strawberry, blackberry, and cape gooseberry. This was carried out in order to guarantee a quality feed (high in antioxidants and physicochemical stable) for the spray-drying process. It is well-known that obtaining a good product in a powder form depends largely on the good quality of the feed suspension. The cape gooseberry, strawberry, and blackberry are fruits with a great variety of bioactive compounds, although they have a short shelf life when they are in a fresh stage. Thus, it is considered important to develop products that largely preserve the nutritional properties of these fruits and at the same time extend their shelf life.

Research on modeling and optimization simulation analysis of micro electric vehicle suspension

Suspension system is one of the key parts of vehicle, the performance of suspension system has great influence on vehicle handling stability and safety. In order to improve the performance of suspension system, the Macpherson suspension of a vehicle is taken as the research object, the suspension model is established by ADAMS/Car, and carried out parallel wheel travel simulation to analyze the key parameters variation of camber angle, toe angle, caster angle, kingpin inclination angle and scrub radius. Simulation results show that camber angle and scrub radius are beyond normal design range and require optimization. Wheel alignment parameters are determined by sensitivity analysis, and optimized by ADAMS/Insight. Then carried out simulation to analyze the performance of optimized suspension system. Results show that optimized suspension system satisfies the requirements of vehicle stability and safety.

A new electric wheel and optimization on its suspension parameters

Hub-driven technology with its many advantages has become a potential transformation technology in the automotive industry. In order to inhibit the negative effects of the in-wheel motor, a new electric wheel configuration was presented with two-stage suspensions, and optimization was conducted for the suspension parameters. With the specially introduced flexible transmission elements and motor suspension, the electric wheel is capable of achieving power transmission and vertical vibration isolation simultaneously. A quarter-vehicle model was established, and vehicle performance-related indices were defined to evaluate the applicability of the new electric wheel. An optimization problem was then constructed for suspension parameters, where constraint conditions were derived according to vehicle dynamics. The optimal solution was sought by a genetic algorithm, aiming at utilizing the full potential of the configuration. Simulations were carried out taking the optimal suspension parameters into account, and comparison was made with vehicles equipped with other electric wheel configurations in terms of these performance indices. The results show that the proposed electric wheel reduces motor vibration, and increases wheel dynamic load and vehicle body acceleration.

Enhanced removal of iron minerals from high-iron bauxite with advanced roasting technology for enrichment of aluminum

High-iron bauxite, which is a typically unmanageable form of bauxite due to its high contents of iron and diaspore, has not been used by alumina producers. An advanced roasting technique for removing iron from high-iron bauxite, based on static pre-roasting in air and suspension roasting by hydrogen under fluidized conditions followed by magnetic separation was developed in this study. The influences of pre-roasting temperature, suspension roasting temperature, roasting time, and H2 concentration were investigated. The phase transformations of the samples were investigated using X-ray diffraction, vibrating sample magnetometry, field emission scanning electron microscopy, and Brunauer-Emmett-Teller method. After pre-roasting at a temperature of 750 °C for 30 min, diaspore (AlOOH) and goethite (FeOOH) in the raw high-iron bauxite ore were transformed into Al2O3 and Fe2O3, respectively. The optimal suspension roasting conditions were determined to be a roasting temperature of 600 °C with a H2 concentration of 25% for 4 min. The reduction sample was subjected to magnetic separation and a non-magnetic product (aluminum concentrate), with alumina recovery of 80.64% and iron removal of 85.32%, was obtained. Such a non-magnetic product could be used as a raw material for the Bayer process in the alumina production industry, while the magnetic product could be used as a supplementary material for iron ore resources.

Suspension parameter design of underframe equipment considering series stiffness of shock absorber

In this article, a vertical rigid–flexible coupling model between the vehicle and the equipment is established. Considering the series stiffness of hydraulic shock absorbers, the underframe equipment is like a three-element-type Maxwell model dynamic vibration absorber. The carbody is approximated by an elastic beam and the three-element-type dynamic vibration absorber for general beam system was studied by fixed-point theory. The analytical solution of the optimal suspension parameters for the beam system subjected to harmonic excitation is obtained. The dynamic vibration absorber theory is applied to reduce the resonance of the carbody and to design the suspension parameters of the underframe equipment accordingly. Then, the railway vehicle model was established by multi-body dynamics simulation software, and the vibration levels of the vehicle at different speeds were calculated. A comparative analysis was made between the vehicles whose underframe equipment was suspended by the three-element-type dynamic vibration absorber model and the Kelvin–Voigt-type dynamic vibration absorber model, respectively. The results show that, compared with the vehicle whose underframe equipment is suspended by the Kelvin–Voigt-type dynamic vibration absorber model, the vehicle whose underframe equipment is suspended by the three-element-type dynamic vibration absorber model can achieve a much better ride quality and root mean square value of the vibration acceleration of the carbody. The carbody elastic vibration can be reduced and the vehicle ride quality can be improved effectively using the designed absorber.

Lattice Boltzmann Computations of Natural Convection Heat Transfer of Nanofluid in a Square Cavity Heated by Protruding Heat Source

Abstract This paper reported the mathematical modeling and numerical simulation of natural convection flow of Cu/water nanofluid in a square enclosure using the lattice Boltzmann method (LBM). The cavity is heated from below by heat source and cooled by the top wall. The vertical walls are adiabatic. After validating the numerical code against the numerical and experimental data, simulations were performed for different Rayleigh numbers (104–0.5 × 107), nanoparticles volume fractions (0–8%), and cavity inclination angle (0 deg–90 deg). The effects of the studied parameters on the streamlines, on isotherms distributions within the enclosure, and on the local and average Nusselt numbers are investigated. It was found that heat transfer and fluid flow structure depend closely on the nanoparticle concentration. Results show differences in stream separation between a base fluid and the nanofluid. Also, adding small nanoparticles fractions, less than 6%, to the base fluid enhances the heat transfer for higher Rayleigh numbers and cavity inclination angle less than 30 deg. It is concluded that the optimal dilute suspension of copper nanoparticles can be applied as a passive way to enhance heat transfer in natural convection engineering applications.

Effect of SPA-model suspension assembly on the excess-pressure profile measured at a fixed distance from the source

Results of a physical experiment aimed at measuring the profile of relative excess pressure on a control surface in the near zone of the disturbed region of a schematized model of supersonic passenger aircraft (SPA) are reported. Tests in the test section of the T-313 wind tunnel, aimed at identification of the optimum mounting of SPA-model suspension and ensuring measurements of the full profile of the disturbed-pressure wave involving the leading, intermediate, and closing shock waves, were carried out. Comparisons of calculated data with experimental results are presented. Using the revealed optimum model suspension, measurement results in good agreement with the results of numerical calculations are obtained. The numerical solution to the problem about the flow around the geometric model was obtained and the necessary measurements in the experiment were carried out at freestream Mach number M∞ = 2.04 and angle of attack α = 4°.