Suspension Structure Research Articles

Research on Inertial Force Attenuation Structure and Semi-Active Control of Regenerative Suspension

To improve the energy recovery ability of the energy-regenerative suspension, a transmission is generally used to increase the motor speed, but this results in a significant increase in the equivalent inertial mass of the suspension. The research on energy-regenerative suspension has been ongoing for more than 20 years, but there have been few product applications, mainly due to the failure to solve the problem of the deterioration of suspension performance caused by equivalent inertial mass. This paper proposes a new suspension configuration with the suspension shock absorber connected to a high-frequency vibration reduction structure and establishes a vibration transmission model. Through frequency domain analysis, it has been conclusively proven that the new-configuration can significantly reduce both the sprung mass acceleration and relative dynamic load of the energy regenerative suspension. On the basis of frequency domain analysis, a scheme based on PWM control of the dissipation resistance value of the energy regenerative suspension is proposed, and through bench comparison experiments, it has been verified that the new-configuration suspension can eliminate the oscillation of the damping force curve of the shock absorber and significantly improve the suspension performance. Further experiments show that using the skyhook semi-active control algorithm the new-configuration suspension can further reduce the sprung mass acceleration and relative dynamic load.

Non-Linear Behaviour and Analysis of Innovative Suspension Steel Roof Structures

Suspension structures are one of the most effective roof load-bearing structures for medium to long spans. Their shape under symmetric loads is usually a square parabola or a curve close to it. The biggest drawback of such structures is their increased deformability under asymmetric loads. So-called rigid cables are used to solve this problem. However, the production of such rigid cables with a curvilinear shape is complicated, and their maintenance also has drawbacks due to the above-mentioned shape. To avoid these shortcomings, straight-line suspension structures have been used. This paper proposes a new form of combined suspension roof structures consisting of main load-bearing straight suspension elements supported by cable struts. For the main suspension elements, the bending stiffness is accepted, taking into account the operational requirements of the structure. This article analyses the behaviour of such a combined suspension structural system in symmetric conditions with an innovative approach. The arrangements of this system are discussed. The calculation of the forces and displacements of this structure and its elements is presented, taking into account the geometrical nonlinear behaviour. The distribution of the forces in the rigid elements and node displacements of the structure are discussed. The proposed new form of a combined cable-supported roof structure was shown to be more effective in terms of weight than the standard parabolic-shaped suspension structure.

Finite element analysis and experimental study of strain for a vehicle rear suspension

In this paper, aspects of the study of the durability of rear suspension components of a vehicle are discussed. These aspects are addressed in two ways, namely the study by CAD modelling and finite element method simulation, and secondly by experimental analysis on a durability test bench. In order to develop these research problems, an experimental stand is virtually modelled and studied by simulation using ADAMS software. Results are obtained that characterize the operation of the test bench system kinematically and dynamically. The studies are then completed by finite element analysis of the dependent rear axle and helical springs in the suspension structure. These results are corroborated with those obtained experimentally, i.e. stresses and strains recorded on the stand. The usefulness of these studies is that they allow the validation of different components of the rear suspension in terms of fatigue strength and different types of rear axles from cars can be tested, as the stand has a modular construction and the test parameters can be adjusted.

Influence of rotor impeller structure on performance improvement of suspended axial flow blood pumps.

The hydrodynamic suspension structure design of the axial blood pump impeller can avoid the problems associated with using mechanical bearings. However, the particular impeller structure will impact the hydraulic performance and hemolysis of the blood pump. This article combines computational fluid dynamics (CFD) with the Lagrange particle tracking method, aiming to improve the blood pump's hydraulic and hemolysis performance. It analyzes the flow characteristics and hemolysis performance inside the pump. It optimizes the taper of the impeller hub, the number of blades, and the inclination angle of the circumferential groove at the top of the blade. Under certain rotational speed conditions, an increase in the taper of the impeller hub or the number of blades can increase the pumping pressure of a blood pump, but an increase in the number of blades will reduce the flow rate. The design of circumferential grooves at the top of the blade can increase the pumping pressure to a certain extent, with little impact on the hemolysis performance. The impeller structure is optimized based on the estimated hemolysis of each impeller model blood pump. It could be seen that when the pump blood pressure and flow rate were reached, the optimized impeller speed was reduced by 11.4%, and the estimated hemolysis value was reduced by 10.5%. In this paper, the rotor impeller structure of the blood pump was optimized to improve the hydraulic and hemolytic performance effectively, which can provide a reference for the related research of the axial flow blood pump using hydraulic suspension.

NEW DESIGN OF SPRING-HYDRAULIC SUSPENSION OF VEHICLE WHEELS

The designs of independent suspensions of vehicle wheels (single-lever with levers of equal thickness, double-lever with levers of different lengths, lever-telescopic, double-lever with torsion bar) are considered. The complexity of suspension structures and their low reliability in conditions of poor cross-country is noted. The ensures stabile damping efficiency in any direction of movement and comfortable steering. The absence of a complex lever system in the suspension design increases its reliability.

Design and optimization of H-type asymmetric magnetic suspension vibration absorber for ships

The active–passive hybrid vibration isolation technology emerges with the advancement of the requirements for ship vibration and noise reduction. Among these, the magnetic suspension damper based on magnetic suspension technology has received more attention. In this paper, the effects of magnetic pole area and control current on the magnetic flux density and suspension force are verified by establishing a magnetic suspension structure model and comparing and verifying the results carried out by combining the theoretical formulas and finite element simulation. By exploring the effect of the structure on the magnetic flux density and suspension force, a new H-type asymmetric magnetic suspension structure is proposed and simulated. The results show that the H-type asymmetric magnetic suspension structure is more successful at improving the suspension force while also widening the suspension force response interval and improving the performance of the magnetic suspension damper. In addition to offering a new design concept for the construction of ship vibration and noise reduction structures, this structural solution serves as a reference for the development of magnetic suspension dampers.

On rheological properties of disc-shaped cellulose nanocrystals

The rheological properties of a substance depend greatly on its morphology, and rod-shaped cellulose nanocrystals (RCNCs) and cellulose nanofibrils (CNFs) have been extensively studied for their rheological properties. Nevertheless, the rheological properties of disc-shaped cellulose nanocrystals (DCNCs) with crystalline allomorph II derived from mercerized cellulose remain unknown yet. This work investigated the DCNCs' rheological properties in depth using steady-shear and oscillation measurements. At the same concentration, DCNC's suspension viscosity is lower than that of RCNC; RCNC has an instinct viscosity of 258.2, while DCNC has 187.9. Comparing RCNC suspensions with cellulose nanorods, DCNC has a lower aspect ratio and exhibits a distinct steady shear behavior. Under polarized film, DCNC suspension cannot self-assemble into chiral or liquid crystal phases, and with increasing concentrations, the system transitions from an isotropic phase to a gel phase. Oscillation sweeps demonstrate that the gel transition occurs at 7 %–8 %. Based on thixotropic recovery sweep outcomes, the high-stress oscillations enhance the network structure of DCNC suspensions, which is significantly different from that of RCNC suspensions. Results demonstrate the unique properties of DCNC, highlighting its application as a rheological modifier.

Time evolution of the inner structure of antimony phosphate nanosheet suspension developing structural colouration.

Structural colouration observed in antimony phosphate nanosheet suspensions has been known for two decades, but the stability of their inner structures has not been a topic in colloidal nanosheet systems. In this study, we investigate the time evolution of structures in suspension using UV-visible spectrometry and small-angle X-ray scattering. Here, we report that antimony phosphate nanosheet systems re-organise their inner structures, especially at lower concentrations (isotropic or biphasic region), and that the basal spacing decreases with time after sample preparation, although the evolution speed depends on the sample concentration. The stability of the inner structure of the suspension is essential for their application as structural colour materials in sensors and colourants.

Structure and short-time diffusion of concentrated suspensions consisting of silicone-stabilised PMMA particles: a quantitative analysis taking polydispersity effects into account.

We characterise structure and dynamics of concentrated suspensions of silicone-stabilised PMMA particles immersed in index-matching decalin-tetralin mixtures by means of static and quasielastic light scattering experiments. These particles can reproducibly be prepared via a comparatively easy route and are thus promising model systems with hard-sphere interaction. We demonstrate the hard-sphere behaviour of dense suspensions of these systems rigorously taking polydispersity effects into account. Structure factors S(Q) can in the entire range of volume fractions with liquid-like structure quantitatively be modelled using a multi-component Percus-Yevick ansatz regarding the particle size distribution and the form factor assuming a core-shell model with a scattering length density gradient in the PMMA core. Herewith, hydrodynamic functions H(Q) are in the whole accessible Q-range beyond the second maximum of H(Q) quantitatively modelled using a rescaled δγ-approach for all investigated volume fractions. With these data, previously provided characterisation of dilute systems is extended: the excellent agreement of structural and dynamic properties with theoretical predictions for hard spheres demonstrates the suitability of these particles as a model system for hard spheres.

Structure and dynamics in suspensions of magnetic platelets.

In this research, we employ Brownian dynamics simulations, density functional theory, and mean-field theory to explore the profound influence of shape anisotropy of magnetic nanoplatelets on suspension magnetic response. Each platelet is modelled as an oblate cylinder with a longitudinal point dipole, with an emphasis on strong dipolar interactions conducive to self-assembly. We investigate static structural and magnetic properties, characterising the system through pair distribution function, static structure factor, and cluster-size distribution. The findings demonstrate that shape-specific interactions and clustering lead to significant changes in reorientational relaxation times. Under zero field, distinctive modes in the dynamic magnetic susceptibility identify individual particles and particle clusters. In the presence of an applied field, the characteristic relaxation time of clusters increases, while that of single particles decreases. This research provides insights into the intricate interplay between shape anisotropy, clustering, and magnetic response in platelet suspensions, offering valuable perspectives for recent experimental observations.

Time domain analysis of catenary response characteristics caused by ambient wind

Abstract The catenary system, as a framework within railway electrification projects, constitutes an exposed suspension structure deployed along railway lines. It serves the purpose of providing electrical power to electric locomotives through pantographs but lacks backup facilities and falls into the category of a specialized form of high-voltage transmission line. To ensure the safety and reliability of the catenary system and the stable current collection of the pantograph, thereby safeguarding railway operational safety, it is imperative to research the aerodynamic response of the catenary system induced by environmental winds. For this study, the catenary system in the 4m windbreak wall section of the Lanzhou-Xinjiang high-speed railway bridge has been selected as the research subject. To determine wind speed correction coefficients at the supporting cable and contact wire locations, a finite element model was created using wind tunnel experiments and numerical simulations. Samples of wind speed fluctuation have been obtained using the harmonic synthesis method. Based on quasi-steady aerodynamic theory, a temporal analysis has been conducted on the aerodynamic response of supporting cables and contact wires under the influence of both average and fluctuating winds. Temporal results, such as lift at positive and negative positioning locations and mid-span displacement, have been extracted to assess whether the existing structure complies with regulatory requirements. This study offers valuable insights for engineering applications that are similar.

应用于高地隙自走式喷雾机的独立式立轴空气悬架设计与分析

As an important plant protection machinery for spraying and fertilizing crops, high clearance self-propelled sprayer is of great significance to promote food security production and stable development of agriculture. Aiming at the complex operating conditions and unique operating requirements of large high clearance self-propelled sprayer, this paper analyzes and determines the main components of the sprayer suspension, such as elastic components, guiding devices, buffer devices, damping components, etc., and designs a stand-alone vertical shaft air suspension system structure suitable for high clearance sprayers. The stress of the sprayer chassis under different extreme conditions such as side slip, emergency braking and uneven road driving is analyzed, and the vertical shaft is designed and checked in detail. Based on the stress analysis results of the sprayer chassis, the finite element analysis software HyperMesh 10.0 was used to analyze the statics of the key components of the suspension, such as the vertical shaft, the motor protection shell, the steering arm, and the spring top support. According to the results of force analysis and finite element analysis, combined with the requirements of process production, the suspension structure in the design scheme is improved, and the final suspension form and the whole structure scheme of the sprayer are obtained. Through this study, it provides a basis for the design and development of large high clearance self-propelled sprayer.

Thermophysical properties of suspensions with [NI₃(μ₃-PPZA)₄CL₂] metal string complex microparticles

The study investigated the thermophysical properties of suspensions containing Ni₃(μ₃-ppza)4Cl₂ metal string complex (MSC) microparticles in aqueous glycerol solutions. The results showed that the use of microparticles of monocrystalline metal string complexes Ni₃(μ₃-ppza)4Cl₂ and Ni₅(μ₅-pppmda)4Cl₂ leds to the highest thermal conductivity enhancements and a decrease in freezing point. A comparative analysis of thermal conductivity enhancements of suspensions with micro- and nanoparticles was also conducted. Compared to the base fluid, at 5% volume fraction Ni₃-water-glycerol showed a 72% increase in thermal conductivity, while Cu-water-glycerol and Ni5-water-glycerol showed enhancements of 53% and 47%, respectively. The study suggests that the higher stability of suspensions with MSC microparticles, due to the formation of hydrogen bonds between the organic fragments of particles and water molecules, thier lower density and the formation of particle assemblies, is responsible for the significant thermal conductivity enhancement compared to nanofluids. The colloidal structure of suspensions with MSC microparticles greatly affects their thermophysical properties. Keywords: nanofluid, microfluid, metal string complex, thermal conductivity, suspension.

Experimental and Analytical Studies of String Steel Structure for Bridges

Due to their efficiency, suspension structures are widely used in both roof slabs and different kinds of bridges, from which stress ribbon pedestrian bridges can be distinguished. The main disadvantage of the latter is high deformability, especially under asymmetrical loads. Recently, string structures or their systems have been introduced into bridge building. Numerical and experimental analysis of string behaviour under symmetrical and asymmetrical loads is carried out in the article. Analytical expressions for the calculation of string displacements and tensile forces are presented. The impact of the string pre-stress on the state of its stresses and deformations was evaluated. The assessment of the accuracy of analytical expressions by applying the results of numerical and experimental research is presented. A methodology is proposed for calculating the pre-stressing force taking into account the operational requirements. Three main loading options at different string pre-stress values are analysed. It is worth mentioning that the difference (error) between the analytical and numerical results is not extensive, it does not exceed 3%. It is necessary to notice that in all cases, the analytically obtained results are somewhat higher than FEM (numerically) obtained results.

Angle-Independent Color Change in Thermoresponsive Gel-Immobilized Colloidal Amorphous Film Attached to PET Substrate.

Gel-immobilized colloidal amorphous structures comprise short-range-ordered monodisperse submicrometer particles embedded into a soft polymer gel. They exhibit an angle-independent structural color that is tunable in response to external stimuli via a volume change in the gel, which has significant potential for the development of sensors that respond to stimuli via angle-independent color changes. In this study, the amorphous structure of a charged colloidal suspension in water was immobilized in a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) gel film and simultaneously attached to a polyethylene terephthalate (PET) substrate. The gel film exhibited a uniform angle-independent color that changed in response to changes in temperature (i.e., thermosensitivity). Attachment to the PET substrate suppressed changes in the gel film area and film distortion, despite significant volume changes in the gel. Consequently, the degree of thermosensitivity was enhanced. The PET-attached gel-immobilized colloidal amorphous film was easy to handle and had excellent flexibility, allowing it to wrap around the surfaces of curved objects. These features are advantageous for sensor applications.

Experimental and Analytical Studies of String Steel Structure for Bridges

Due to their efficiency, suspension structures are widely used in both roof slabs and different kinds of bridges, from which stress ribbon pedestrian bridges can be distinguished. The main disadvantage of the latter is high deformability, especially under asymmetrical loads. Recently, string structures or their systems have been introduced into bridge building. Numerical and experimental analysis of string behaviour under symmetrical and asymmetrical loads is carried out in the article. Analytical expressions for the calculation of string displacements and tensile forces are presented. The impact of the string pre-stress on the state of its stresses and deformations was evaluated. The assessment of the accuracy of analytical expressions by applying the results of numerical and experimental research is presented. A methodology is proposed for calculating the pre-stressing force taking into account the operational requirements. Three main loading options at different string pre-stress values are analysed. It is worth mentioning that the difference (error) between the analytical and numerical results is not extensive, it does not exceed 3%. It is necessary to notice that in all cases, the analytically obtained results are somewhat higher than FEM (numerically) obtained results.

Electrorheological Effect of Suspensions of Polyaniline Nanoparticles with Different Morphologies.

Polyaniline (PANI) nanospheres, nanofibers, and nanoplates were prepared using the oxidative polymerization method. Scanning electron microscopy (SEM) was used to observe the three morphologies of PANI, and their structure was tested using infrared spectroscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. The influence of particle morphology on the electrorheological (ER) effect was studied through rheological experiments and molecular dynamics (MD) simulation. The experimental and simulation results indicate that without applying an electric field, the nanofibers easily form a three-dimensional network structure in the suspension, resulting in yield stress. The three-dimensional network structure of the nanoplate suspension becomes weaker and the PANI nanosphere suspension lacks the ability to form a three-dimensional network structure. After applying an electric field, under the same condition, the yield stress and electric field-induced shear stress increment of PANI nanofibers are the highest, followed by nanoplates, and those of PANI nanospheres are the lowest. This indicates that the ER effect increases with the increase in particle morphology anisotropy. Through three-dimensional visual simulation analysis, it can be concluded that the enhanced ER effect associated with increased particle anisotropy can be attributed to improved stability in the ER chain structure.

Effective interactions, structure, and pressure in charge-stabilized colloidal suspensions: Critical assessment of charge renormalization methods.

Charge-stabilized colloidal suspensions display a rich variety of microstructural and thermodynamic properties, which are determined by electro-steric interactions between all ionic species. The large size asymmetry between molecular-scale microions and colloidal macroions allows the microion degrees of freedom to be integrated out, leading to an effective one-component model of microion-dressed colloidal quasi-particles. For highly charged colloids with strong macroion-microion correlations, nonlinear effects can be incorporated into effective interactions by means of charge renormalization methods. Here, we compare and partially extend several practical mean-field methods of calculating renormalized colloidal interaction parameters, including effective charges and screening constants, as functions of concentration and ionic strength. Within the one-component description, we compute structural and thermodynamic properties from the effective interactions and assess the accuracy of the different methods by comparing predictions with elaborate primitive-model simulations [P. Linse, J. Chem. Phys. 113, 4359 (2000)]. We also compare various prescriptions for the osmotic pressure of suspensions in Donnan equilibrium with a salt ion reservoir and analyze instances where the macroion effective charge becomes larger than the bare one. The methods assessed include single-center cell, jellium, and multi-center mean-field theories. The strengths and weaknesses of the various methods are critically assessed, with the aim of guiding optimal and accurate implementations.

The development and engineering practice of building cable structures in China

This paper introduces the development process of building cable structures in China over the past 70 years according to three stages: the initial, slow, and rapid development. It also summarizes the types of cable components and joints of building cable structures. The structural characteristics and representative projects of suspension, cable membrane, beam string (cable-supported), and cable dome structures are reviewed in this paper. Finally, the achievements and prospects of cable structures in China are discussed.

Layout Optimization and Performance Analysis of Vehicle Suspension System Using an Electromagnetic Inerter

The inerter is a vibration isolation device used to replace the mass element in classical vibration isolation theory. The introduction of an inerter into a vehicle suspension system can greatly improve the performance of the system. An electromagnetic inerter is a kind of device that can realize a complex suspension structure without an additional energy supply and a complicated control system. It not only utilizes hydraulic systems to attain various suspension mechanical structures but also incorporates linear generators to form more intricate electrical networks. In this paper, an approach is proposed to achieve an optimized vehicle suspension layout using an electromagnetic inerter, which promotes the practical application of the device. First, seven suspension layouts are presented based on this device and relevant models are established to optimize the performance of these seven layouts under certain objectives. Then, the influence of three factors of the electrical network, namely linear generator internal resistance, inductance, and linear generator coefficient, on suspension performance is analyzed. At the same time, to ensure the suspension performance of this device is closer to that required for actual engineering applications, the improvement in the vibration isolation performance of the device compared with traditional passive suspension is discussed considering these three factors. The final results show that when considering the real-world situation, the L1 and L4 layouts can achieve excellent performance improvement, with RMS(BA) values of only 85.73% and 84.66% of the traditional passive suspension.