Wheel Side Research Articles

ADAMS-Based Double Wishbone Suspension Motion Simulation and Optimization

It uses ADAMS software to establish the double wishbone suspension kinematics analysis model to analyze the rules of front wheel alignment parameter changing with wheel run-out and evaluate the rationality of the suspension system data. For the problem of too much side slippage and serious abrasion of front wheel of suspension, it carries out optimization computing for the suspension based on the target of minimizing the front wheel side slippage during wheel run-out. And the optimization result improves the suspension system performance in a certain extent.

Effect of Temperature Gradient on the Microstructure of the Rapidly Solidified Nd–Fe–B Strips

High-performance Nd-Fe-B magnets with nominal composition of Nd13.25Dy0.2Fe78.87Co1Cu0.1Al0.5B6.08 (at%) have been produced by using strip casting technique. It was found that the temperature gradient of alloy in the solidification stage determines the grain size and the grain alignment of the alloy strips. The growth direction of grains parallels the direction of heat flow during solidification stage. The average solidifying rate of strips is more than 103°C/s, which can effectively depress the formation of α-Fe dendrites. It is observed that the concentration of rare earth has a significant decrease from free side to wheel side of the strip. The results of magnetic properties of final magnets produced with different strips indicate that the nonuniform phase structure can deteriorate the squareness of demagnetization curve and the temperature coefficient of coercivity. Effects of the temperature gradient in the solidification process on the microstructure of alloy strips, magnetic properties, and thermal stability of the final magnets are investigated systematically.

Corrosion and Oxidation Behavior of Zr58Cu22Fe4Co4Al12 Metallic Glass

The pitting corrosion behavior of melt spun ribbon made at a wheel speed of 20 ms in 3.5 wt% NaCl solution and nonisothermal and isothermal oxidation behavior of 2 mm diameter rod samples of newly developed Zr58Cu22Fe4Co4Al12 bulk metallic glass have been studied. The pitting corrosion is more on the air side as compared to the wheel side mainly due to the presence of air pockets. The pitted regions are enriched with copper suggesting dealloying effect due to its noble nature. The alloy shows very good oxidation resistance compared to some of the exiting bulk metallic glass forming alloys. The oxidation leads to the formation of mainly tetragonal ZrO2 with the presence of monoclinic ZrO2, mixture of CuO and Cu2O and Al2O3. Copper in the alloy oxidized progressively with the appearance of white flowery globule shape which later forms interconnected faceted CuO network.

Crystallographic alignment and magnetic anisotropy in melt-spun Nd-Fe-B/α-Fe composite ribbons with different neodymium contents

Crystallographic alignment and magnetic anisotropy were studied for Nd xFe 94- x B 6 ( x=8, 9, 10, 11) ribbons prepared via melt-spinning. Effect of Nd content and wheel speed on the crystal structure and magnetic properties of the ribbons was investigated. Both the free and wheel side of the ribbons could obtain strong c-axis crystal texture of Nd 2Fe 14B phase perpendicular to the ribbons surface at low wheel speed, but the texture weakened gradually with the increase of the wheel speed. Increase of Nd content led to better formation of crystal texture in the ribbons, indicating that the α-Fe phase might undermine the formation of crystal texture. Magnetic measurement results showed that the magnetic anisotropy of the ribbons exhibited corresponding behavior with the invariance of the c-axis crystal texture of Nd 2Fe 14B phase in the ribbons, and the coercivity of the ribbons rose with the increase of both Nd content and wheel speed during melt-spun process.

Cu 첨가에 따른 Nd-Fe-B strip cast의 미세조직과 자기적 특성의 상관관계

Effect of Cu content on microstructural and magnetic properties of a <TEX>$(Nd_{26.06},Dy_{6.51})Fe_{bal.}$</TEX> <TEX>$Cu_xB_{0.97}$</TEX>(wt.%), (x = 0.2, 0.3, 0.4, 0.5) strip-cast was studied. The average inter-lamellar spacing in the free surface and wheel side of the strip cast increased as the Cu content increases. The grain uniformity, the grain alignment, and (00L) texture of the strip cast increased with Cu contents up to 0.4 wt.%. These microstructural changes were attributed to the decrease of the effective cooling rate of the melted alloy caused by the decrease of the melting temperature of resulting from Cu addition. Coercivity and remanence were increased because of the grain alignment and (00L) texture improvement with Cu contents up to 0.4 wt.%.

Microstructure of Rapidly Solidified Al-12Zn-3Mg-1.5Cu Alloy with Zr and Sc Additions

The rapid solidification of Al-12 Zn-3 Mg-1.5 Cu (in mass%) alloy was investigated in order to determine structure changes and the effect of Zr or Sc+Zr additions. Rapidly solidified ribbons with the thickness of 30–50 μm were obtained by a melt spinning technique. The alloys cast into a copper mould were used as a reference material. The mould cast alloys as well as the melt spun ribbons revealed the dendritic microstructure of α(Al) solid solution and η (MgZn2) phase in the interdendritic areas. Additionally the T-Mg32(Zn, Al)49 phase with icosahedral quasicrystalline symmetry was found in the form of small particles located mainly at the wheel side in the Zr or Zr+Sc containing ribbons. The refinement of the microstructure and the reduction of volume fraction of the η phase was observed in the ribbons. Large Al3Zr primary precipitates were observed in the mould cast alloy containing zirconium, while almost whole Zr in the ribbons dissolved in the aluminium solid solution. Annealing of ribbons at 400°C led to the precipitation of spherical L12-Al3Zr or Al3(Sc, Zr) particles, coherent with the matrix. They could be responsible for the improvement of properties of the aluminium alloys by the retardation of recrystallization and grain growth. Plate like precipitates of metastable η′ phase appeared after ageing at 120°C and led to the increase of microhardness up to about 230 HV.

Differences of element distribution between free and wheel side surface of NdFeB/α-Fe ribbons

The ribbons of NdFeB/α-Fe composite alloy were prepared by melt spinning and post crystallizing technique. The element distributions and phase component of both surfaces of as-spun ribbons were measured by energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). Because of the centrifugation, a segregation of B, Fe, and Nd concentrations was observed at the cross section. After crystallizing annealing, the element concentration segregation still existed in the as-crystallized ribbons. Due to the segregation of B, Fe, and Nd, the B-rich phase was observed near the wheel side surface. The B-rich phase may deteriorate the magnetic property of NdFeB/α-Fe composite alloy.

Evolution of crystallographic alignment in Tb-Fe-B melt-spun ribbons

Ternary Tb-Fe-B ribbons were prepared via melt-spun technique under different wheel speeds of 5-25 m/s. Effect of wheel speed on the crystal structure and microstructure of the ribbons was investigated. All the ribbons quenched under different wheel speeds crystallized in single Tb 2Fe 14B phase with tetragon structure. Different crystallographic alignment evolutions were observed in the free side surface and wheel side surface of the ribbons. On the free-side surface, an in-plane c-axis crystal texture of Tb 2Fe 14B phase was found in the ribbons quenched at 5 m/s. However, with the increase in the wheel speed, the direction of the c-axis texture turns to perpendicular to the ribbon surface. On the wheel-side surface, a strong c-axis texture perpendicular to the ribbon surface was observed in the ribbons quenched at 5 m/s, and then weakened gradually with the increase in the wheel speed. Further investigation showed that the competition of the two types of temperature gradients during the quench process was responsible for the crystallographic alignment evolution in the ribbons.

STEADY-STATE CHARACTERISTICS ANALYSIS OF DEEP-SEA RUNNING MECHANISM WITH PLANETARY GEAR WHEEL BASED ON ARTICULATED STEERING RADIUS

Steady-state characteristics analysis for the deep-sea running mechanism with planetary gear train which is designed to adapt to complex terrain in the deep-sea hydrothermal sulfide and rich-cobalt incrustation survey area is based on articulated steering radius. The articulated steering radius formula of the deep-sea running mechanism is derived from the geometric relationship, considering the wheel side slip angle. Based on the formula, three types of steering steady-state characteristic analysis, understeer, neutral steer and oversteer, are made for the mechanism. Steering simulation analysis of the running mechanism with planetary gear is conducted in ADAMS software with different speed. In the process of steering, the side slip angle increases first, then gradually decreases and finally tends to be stable. The side slip angle of the front wheels is greater than that of the rear wheels. While the speed of steering turns to be faster, wheel side slip angle and steering radius increase. The mechanism is understeer, and performs good handling stability characteristic.

Effect of composition on the i-phase cell parameter of Ti–(Zr,Cu)–Ni alloys

Quasicrystalline (i-phase) Ti–Zr–Ni samples were obtained using the melt-spinning technique, where the Ti/Zr ratio ranged from 1 to 3, while the Ni content remained nearly constant, varying between 17 and 20 at. %. We replaced the Zr with 3 and 5 at. % of Cu in order to test the i-phase-forming ability of the samples, which were all subsequently hydrided from the gas phase at 45 bar and 300 °C for 1000 min. We then made XRD analyses of the as-spun and loaded samples in order to determine the influence of the composition and the absorbed hydrogen content on the cell parameter of the i-phase. An almost linear decrease of this parameter with the ([Ti] + [Cu])/[Zr] ratio was found for the as-prepared and hydrided samples, where the slope of the linear fit is preserved after hydrogenation, but with about 6% higher values due to the expansion of the quasilattice. XPS analyses of the melt-spun i-Ti 45Zr 35Ni 17Cu 3 revealed an oxide-layer thickness of 4 nm. A TEM investigation revealed that the size of the i-phase grains on the wheel side of the ribbon was approximately five times smaller than on the bright side, as a result of the higher cooling rate and the resulting faster nucleation rate.

Sb effect on micro structural and mechanical properties of rapidly solidified Al–12Si alloy

The effects of antimony (Sb) addition on the microstructure and mechanical properties of rapidly solidified eutectic Al–Si alloy were investigated. Al–12 wt.%Si– X wt.%Sb ( X = 0, 0.5 and 1.0) alloys were fabricated using a melt-spinner at rotating speeds of 20 m/s. The as-melt-spun ribbons were characterized by a combination of scanning electron microscopy (SEM), X-ray diffraction (XRD) and depth-sensing indentation (DSI) methods. SEM observations showed that 0.5%Sb addition refined the microstructure whereas 1.0%Sb addition led to the formation of coarse Si particles. The wheel side of the ribbons exhibited a finer microstructure than those on the free or air sides exposed to the atmosphere. According to the XRD results, the diffraction patterns of melt-spun ribbons consisted solely of α-Al and Si phases, and a possible volume fraction of AlSb or an intermetallic phase in the alloy was not observed. DSI tests were performed on the ribbons under different loads ranging from 200 to 1200 mN at room temperature. The resulting indentation load-displacement ( P– h) curves were analyzed using the work of indentation approach (WIA) to evaluate the ribbons’ microhardness ( H) and reduced modulus ( Er). We found that the H and Er values of the ribbon decrease with increasing Sb content. This can be attributed to the over modification and changes in the microstructure of Al–12%Si alloy when a minimum of 1.0%Sb is present as a modifier.

Visual estimation of wheel sinkage for rough-terrain mobile robots

For mobile robots driving across natural terrains, it is critical that the dynamic effects occurring at the wheel-terrain interface be taken into account. One of the most prevalent of these effects is wheel sinkage. Wheels can sink to depths sufficient to prevent further motion, possibly leading to danger of entrapment. This paper presents an algorithm for visual estimation of sinkage. We call it the visual sinkage estimation (VSE) method. It assumes the presence of a monocular camera and an artificial pattern, attached to the wheel side, to determine the terrain contact angle. This paper also introduces an analytical model for wheel sinkage in deformable terrain based on terramechanics. To validate the VSE module, firstly, several tests are performed on a single-wheel test bed, under different operating conditions. Secondly, the effectiveness of the proposed approach is proved in real contexts, employing an all-terrain rover travelling on a sandy beach.

Model of Side Contact Layer and Wear Performance of CBN Wheel in Quick-point Grinding Process

Based on the principle and technical characteristcs of point grinding process, the function of the side contact area of the thin CBN point-grinding wheel in material removal process is discussed, and the geometry and parameters models of the side contact area are established. Mathematic modeling and analysis are carried out for the side contact layer parameters, such as the equivalent workpiece diameter, the geometric and dynamic contact arc length, cutting depth of single abrasive grain and average cross-sectional area of chips. The grinding experiment is carried out to study the mechanism of effect of side contact layer parameters on the quick point grinding process and the wear characteristic and rule of thin CBN point-grinding wheel. It is found that the material removal is mainly completed in the side contact layer and the maximum wear rate of the thin CBN point-grinding wheel occurs at the largest circumference of wheel side in the point grinding process.

Thermal Stability of a Rapidly Solidified Cu-Zr

Abstract Rapidly solidified ribbons of Cu-0.7 at.% Zr alloy have been produced by the melt spinning process. An overall assessment of the ribbons shows that the microstructure consists of two morphological zones: a zone with columnar grains at the wheel side and a zone with fine equiaxed grains at the top side of the ribbons. The columnar zone consists of fine Cu-Zr intermetallic particles inside the grains, while in the equiaxed zone we have fine precipitates inside the grains and coarser ones at their boundaries. Transmission electron microscopy was carried out to quantify the coarsening process of the particles. Analysis of particle size showed that the grain boundary particles coarsened noticeably faster than the particles within the copper grains, which coarsened in both morphological zones by bulk diffusion, controlled by the diffusivity of zirconium, and r3—t relationship was obtained at all temperatures of the experiment.

Differences in microstructure and magnetic properties between directly-quenched and optimally-annealed Nd–Fe–B nanocomposite materials

Melt-spun Nd 9.5Fe 81Zr 3B 6.5 ribbons were prepared by the single roller melt-spinning technique. The microstructure and magnetic properties of directly-quenched and optimally-annealed Nd–Fe–B nanocomposite materials were studied by X-ray diffraction, transmission electron microscopy observations, and magnetization measurements. The experimental results show that crystallizing an precursor into nanocrystallines is ineffective for obtaining better magnetic properties, while nanocomposites with excellent properties can be directly melt spinning at an optimum wheel speed. The microstructure of the ribbons at various distances from the ribbon wheel side was studied. It shows that in the inner part of the ribbons, the directly-quenched ribbons and optimally-annealed ribbons have similar characteristics of microstructure. However, in the free-surface and wheel-contacted surface the grain size of the annealed ribbons is much coarser than that of the directly quenched ribbons.

Effect of Ni on the microstructure and precipitate phases of Fe 78Si 9B 13 glassy alloy

The (Fe 0.78Si 0.09B 0.13) 100− x Ni x glassy alloys ( x = 0, 2, 3 and 5) have been investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), Vickers microhardness test, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The experimental results show that the addition of Ni has not only promoted the growth of α-Fe phase and the precipitate of Fe–B compounds but also facilitated the dissolution of silicon in the α-Fe phase. For the as-spun ribbon with x = 5, the microhardness ( H v) of the ribbon with super heating (SH) treatment is lower than that of the ribbon without SH; and the H v of the free side is lower than that of the wheel side of the same ribbon. The saturation magnetization ( M s) of the as-spun (Fe 0.78Si 0.09B 0.13) 95Ni 5 ribbon with SH is higher than that of the ribbon without SH. The variation of the H v and M s is explained by the free volume model which is related to the two structure model in Fe-based glassy alloys, as well as the change of the B content in the amorphous matrix.

Development of a method to compute the kingpin axis using screw axis theory based on suspension-parameter-measuring device data

Kingpin geometry is one of the most important design features in vehicle development, as it determines the steering feeling of drivers, the handling performance, and the steering stability of a vehicle. The idea of a geometric kingpin axis has been used to design a relatively simple suspension mechanism such as a double-wishbone type, and various techniques have been developed to design the kingpin axis of multi-link suspensions. However, a kingpin axis for a real vehicle has been unknown so far because there has been no method to measure or compute it. This paper presents the development of a method to compute the kingpin axis of a vehicle using screw theory and suspension-parameter-measuring device (SPMD) data. SPMD data, such as the wheel centre displacement, toe, camber, and side view angles, are used to derive the finite displacement matrix of the wheel. The finite screw axis is computed on the basis of the displacement matrix, and its compatibility with the kingpin axis is verified by an in-house kinematic analysis program and ADAMS/Car. The result of the finite screw axis method (FSAM) is also verified indirectly by comparing suspension parameters such as the caster trail with the SPMD test result. Both verification results show that the FSAM can successfully compute the kingpin axis of a real vehicle.

FePd melt-spun ribbons and nanowires: Fabrication and magneto-structural properties

Fe–30%Pd alloys in ribbon and nanowire geometry have been prepared. Ribbon samples were produced by the melt-spinning technique in the Ar environment. FePd nanowires, having about 35 nm in diameter, 105 nm inter-nanowires distance and around 4 μm in length, were synthesized into nanoporous anodic alumina membranes as templates. Energy dispersive X-ray microanalysis of ribbons shows an average atomic composition of Fe (73.2%) and Pd (26.8%). The X-ray diffraction at RT analysis was performed on both surfaces, free and wheel side, of the melt-spun ribbon. It shows the coexistence of two phases: fct and bct FePd, but with differences between both surfaces consisting the existence of Fe oxides (Fe 2O 3 and Fe 3O 4) and a textured 200 reflection in the free side. Heating and cooling thermomagnetic curves exhibit a reversible behaviour from RT to 720 K, but around 770 K a clear irreversible transformation takes place.

Exchange Bias in Surface-Crystalline Fe-Nb-B Ribbons

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Exchange bias in Fe-Nb-B ribbons is investigated. The as-quenched ribbon exhibits partial crystallinity on both surfaces while the bulk of ribbon is amorphous. The coexistence of amorphous phase and crystalline <formula formulatype="inline"> <tex Notation="TeX">$\alpha$</tex></formula>-Fe on the ribbon surfaces is confirmed by X-ray diffraction, conversion electron MÖssbauer spectroscopy (CEMS), and transmission electron microscopy (TEM). The crystalline phase can be removed by a short etching in a diluted nitric acid. The properties of the two surfaces are different. A high concentration of the crystallites in a very thin layer at the surface is typical for the wheel side. On the shiny side the crystallites are spread, with the volume fraction about 5%, in a layer about 1.5 <formula formulatype="inline"><tex Notation="TeX">$\mu$</tex> </formula>m thick. Whereas the amorphous phase is magnetically soft (<formula formulatype="inline"><tex Notation="TeX">$H_{c} \approx$</tex></formula> 3.5 A/m), the coercive fields of the surface layers, measured by magneto-optic Kerr effect (MOKE), are 0.8 and 3.2 kA/m for the wheel and shiny side, respectively. Bulk hysteresis loops of strained ribbons (straight or toroids) are usually asymmetric and shifted with respect to zero magnetic field. It is shown that mainly the surface layer on the shiny side is responsible for this bias effect. An explanation based on the exchange coupling between the Fe grains and the amorphous phase is proposed. </para>

Crystallization of NANOPERM-type amorphous alloys

In the present work, we have investigated progress of crystallization in the Fe 91− x Mo 8Cu 1B x ( x = 12, 15, 17, 20) alloy as a function of annealing temperature. This material belongs to the family of the Fe–M–B–(Cu) alloys (transition metal M = Zr, Nb, Hf, Mo, …) called also NANOPERM. The alloy was found to contain small amounts (<5%) of bcc Fe(Mo) and Mo 2FeB 2 nanocrystallites (<2 nm) located on the surface of the ribbon-shaped samples already in the as-quenched state. Depending upon composition, the nanocrystallites are formed on the air and/or wheel side of the ribbon. They are characterized by atomic force microscopy, conversion electron Mössbauer spectroscopy, and by X-ray diffraction of synchrotron radiation. Fast detection (every 10 s) of the latter during continuous heating of as-quenched specimens enabled an in situ observation of the evolution of the crystallization. For x = 12, the crystallization starts earlier at the wheel side of the ribbon but its progress is more rapid at the opposite, i.e. air side.