Static Wheel Load Research Articles

Thermal and structural evaluation of an asphalt pavement with an embedded inductive power transfer pad for stationary charging of EVs

A key strategy for increasing sustainability in transportation is to increase the use of Electric Vehicles (EVs) worldwide. Charging EVs wirelessly utilizing Inductive Power Transfer (IPT) pads eliminates most of the current limitations of EVs, such as range anxiety. In this study, the effect of an IPT pad on the temperature and strain response of an asphalt mixture was evaluated. A scaled IPT pad was placed into an experimental asphalt slab and the IPT-asphalt temperature, while energizing the IPT pad, was determined by a thermal camera, Fibre Bragg Grating (FBG) sensors, and thermistors. Moreover, a static wheel load was applied on the surface of the asphalt slab, with and without an IPT pad, and the horizontal tensile strain adjacent to the bottom of the asphalt slab was measured using an FBG sensor. ANSYS simulations were conducted and were validated using the experimental results. The results showed that embedding an energized IPT pad into the asphalt slab at 20 °C increased the asphalt’s surface temperature (approximately 32 mm offset from the pad) by 8.3 °C in the experiment. Raising the ambient temperature from 20 to 50 °C resulted in an elevation of the asphalt surface temperature from 28.3 to 56.7 °C in the experimental analysis. Placement of the IPT pad into the asphalt slab was seen to decrease the asphalt strain by 41 % in the experiment. Placing the static wheel load on the edge of the pad increases the maximum tensile strain by 16 % and moving the load 66.4 mm from the edge increases the maximum tensile strain by 54 %. Significantly, applying both the thermal load and the static wheel load increased the maximum tensile strain by 53 % compared to the asphalt slab without an IPT pad.

Effect of complex climatic and wheel load conditions on resilient modulus of unsaturated subgrade soil

Resilient modulus (Mr) is a fundamental mechanical property vital for assessing the resistance of pavement structures to cyclic vertical loads. It has played a pivotal role in pavement design and has been instrumental in predicting pavement responses and fatigue life. The Mr of subgrade soil is affected by a multitude of factors, including stress, moisture, and temperature conditions, all of which interact to define the response of the soil. This research investigated the effect of complex climatic conditions on Mr with a particular focus on areas experiencing significant seasonal changes in snowy cold regions like Hokkaido, Japan. Previous studies have proposed predictive models for Mr, incorporating the concept of matric suction, to account for moisture conditions. However, these models have rarely considered suction hysteresis in the soil–water characteristic curve (SWCC) or the effects of wheel loading on frost-susceptible subgrade soil during different seasons. In this study, a series of Mr tests were conducted on two types of subgrade soil under various climatic and wheel loading conditions. The test results promise to enhance our understanding of the complex interplay of climatic and stress conditions on Mr of standard sand and frost susceptible subgrade soil along different drying and wetting paths, particularly in regions with significant seasonal variations.

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.

Abrasion Characteristics of Exposed Aggregate Concrete Pavements under Surface Deterioration

This study compares the abrasion characteristics of concrete pavements with exposed aggregates and transverse tining textures under surface deterioration conditions. Deicer scaling resistance tests and dressing wheel abrasion tests were conducted to simulate surface deterioration under environmental and wheel loading conditions, respectively. Dressing wheel abrasion tests showed that the abrasion depths in concrete with 8 mm and 10 mm exposed aggregate textures were 43% and 36% lower, respectively, than those with transverse tining surface textures. After 40 cycles of the deicer scaling resistance test, the abrasion depth in the tining surface textured concrete did not satisfy the abrasion criterion of concrete pavements. Therefore, the long-term durability of the exposed aggregate texture can be ensured against abrasion and surface deterioration resistance during the pavement service life.

Discussion of “Undrained Cyclic Response of K0-Consolidated Stiff Cretaceous Clay under Wheel Loading Conditions” by K. Pan, X. M. Liu, Z. X. Yang, R. J. Jardine, and Y. Q. Cai

Discussion of “Undrained Cyclic Response of K0-Consolidated Stiff Cretaceous Clay under Wheel Loading Conditions” by K. Pan, X. M. Liu, Z. X. Yang, R. J. Jardine, and Y. Q. Cai

Closure to “Undrained Cyclic Response of K0-Consolidated Stiff Cretaceous Clay under Wheel Loading Conditions” by K. Pan, X. M. Liu, Z. X. Yang, R. J. Jardine, and Y. Q. Cai

Closure to “Undrained Cyclic Response of K0-Consolidated Stiff Cretaceous Clay under Wheel Loading Conditions” by K. Pan, X. M. Liu, Z. X. Yang, R. J. Jardine, and Y. Q. Cai

Laboratory Assessment of Coir Geotextile Mats Under Wheel Load Conditions for Low-Volume Roads (LVRs)

The present study brought out the effort and quantifies the use of geotextile in Low-Volume Roads over the weak subgrade. The Low-Volume Roads (LVRs) play a key role in the economic growth of rural area as well as helps in developing the country. The construction of these LVRs over the weak strength of soil subgrade is a challenging task for civil engineering to provide the safe and smooth flow of traffic, and such soil is revealed that the Black Cotton soil (BC). The weak soil subgrade consists the finer particles like clay and silt showing poor shear strength, bearing capacity, and California bearing ration values. It poses several serious problems to the LVRs. To arrest these problems many of the conventional techniques were adopted in pavement application. But these techniques are nor economical and neither eco-friendly. To reduce this problem, the cost of construction, and to provide a longer duration, geosynthetics are introduced as an alternate material in pavement application in the last few decades. In the umbrella of geosynthetics, the geotextile is gaining attention for its utilization in pavement constructions. The study found the coir composite mats performed better reinforcement and improved the strength of the pavements. This study concluded that the use of coir geotextile mats with appropriate of sub-base soil at the suitable position at H/4 with morrum soil improved the performance of the LVRs with 200mm thickness of mould over the 400 mm thickness of the mould. It is indicate a decrease in construction and maintenance costs of the LVRs.

Evaluation on the full-scale testbed performance of lightweight foamed soil using railroad loading system

The accumulated critical settlement usually occurs at the railway bridge approach zone due to the sudden variation in track stiffness and the difference in foundation property. This problem leads to the fast degradation of the whole track structure. Therefore, this research aims to develop a novel backfill material that helps improve the displacement resistance of the track’s supporting layer. The new flowable fill material is designed to gain the advantage of self-leveling, lightweight, and strong stress-bearing capacity through utilizing of local excavated soil, cement, and preformed foam. To cope with this objective, three full-scale testbed sections were constructed including a controlled section (conventional cement treated base), lightweight clay soil section (CL), and lightweight silty soil section (SM). Using the railroad loading system (RSL) to replicate actual trainload behaviour, a static wheel load (0-120kN) and dynamic wheel load (600,000 cyclic sinusoidal loads, 5 Hz) are applied on the surface to record the internal roadbed pressure, elastic, and plastic displacement of the backfill layer. Test results indicate significant improvement of both novel backfill materials compared to conventional cement treated base. With an average reduction for roadbed pressure and displacement of >35% on static loading, and >30% on dynamic loads. Track stiffness was also improved by up to 40% after 300,000 cyclic loads. Overall, all three sections meet the Korea roadbed design standards having a plastic settlement < 3 mm after 1 million dynamic trainloads. This promising solution can be applied in multiple regions to promote the development of sustainable railway backfill at bridge transition.

Three-dimensional tire-pavement contact stresses prediction by deep learning approach

ABSTRACT The demand for fast and accurate tire-pavement contact modelling is becoming increasingly prevalent with the advancement of pavement design and finite-element modelling. This paper presents a tool for fast and accurate prediction of non-uniform tire-pavement contact stresses utilising deep learning. Two truck tires, under various wheel loading, inflation pressure, and slip ratio conditions, were considered. The developed deep learning model, ContactNet, is a deconvolutional neural network consisting of two fully connected layers, one reshape layer, and five deconvolution layers with millions of neurons. Two validated finite-element truck tire models were used to generate a contact stresses database with 1800 simulated results. The database was then used for training and testing of the ContactNet. The ContactNet resulted in average errors of 0.80%, 0.77%, 0.90%, and 0.57% in predicting maximum vertical stress, effective contact area, maximum longitudinal stress, and maximum transverse stress. The mean absolute error of the ContactNet prediction is 0.91 kPa. This significantly outperformed four conventional machine-learning regression methods investigated in this study, including polynomial regression, k-nearest neighbours, multi-layer perceptron, and random forests.

Undrained Cyclic Response of K0–Consolidated Stiff Cretaceous Clay under Wheel Loading Conditions

AbstractOptimal whole life design for railways, highways, runways, and metro lines requires an accurate assessment of how their underlying geomaterials respond to large numbers of wheel-loading cyc...

Soil structure response to field traffic: Effects of traction and repeated wheeling

Soil compaction caused by the use of heavy agriculture machinery in non-optimal soil conditions hampers crucial soil functions. Tyre inflation pressure and wheel load are well-known key drivers of compaction. The effects of traction and repeated wheeling are, however, not yet fully understood but may be of critical importance. We aimed to quantify the effects of traction and repeated wheeling on some soil structural properties independently in a compaction experiment conducted on a sandy loam at a soil water content near field capacity, using a tractor-trailer combination at two loads. The trailer was used in ‘standard’ and ‘offset’ steering modes, the latter referring to the mode in which measurements could be taken for the pass of a single towed and thereby passive trailer wheel (with one, two, three and six wheel passes). Penetration resistance was measured to 0.71 m depth and 100-cm3 soil cores were collected around 0.16 m depth for structural property measurements. In the offset steering mode, the measurements were made in the tractor tracks to investigate the effect of traction and in the trailer’s wheel track to investigate the effect of repeated wheeling (at 6.0 Mg static wheel load). The measurements were also collected for the standard steering configuration with the high towed load and from reference plots. Measurements on the soil cores comprised bulk density, porosity, and air permeability. We found a clear effect of traction on deformation of some soil structural properties, with no significant effects of the low drawbar pull but with substantial effects of the high drawbar pull. Reductions in air permeability and specific permeability were significant (89 % and 83 %, respectively) and indicated a densification and homogenisation of the soil. The effect of repeated wheeling was gradual and reasonably well explained by a linear fit to the number of wheel passes. After six passes with the passive wheel caused some soil structural properties to differ significantly from the reference soil, and resulted in approximately similar levels of bulk density, porosity, air permeability and specific permeability as the tractor with high drawbar pull. Still, the deformation was stronger for the single pass of the tractor with the high drawbar pull than for six repeated wheeling of the passive trailer wheel. These results highlight the substantial effect of traction on soil compaction. Yet, the mechanisms causing this deformation remain speculative until the propagation of horizontal stress through the soil profile is better understood.

Stress analysis in upper fillet and rail-end bolt hole at rail joint

Rail joint between two adjacent rail ends in the transportation of railway track structure is one of the weakest components leading to defects and failures. In this study, the rail joint components such as rail, joint bars, bolts, and sleeper are modelled by 3D Abaqus/CAE software and Finite-element method are used to investigate stress distribution in rail under static wheel load condition. The wheel load positions and bolt-hole locations vary as a parametric study. The results show that the critical stress occurs at the upper fillet rail end and at the edge of the rail-end bolt hole (1st hole from the rail end). The wheel load position affects stress only in case of the rail-end bolt hole located at 80 mm from the end. In addition, overall trends for the effect of rail-end bolt hole positions are similar in which the stress decreases when the distance from rail end to the rail-end bolt hole increases. Taken together, these findings suggest stress distribution is the basic information that helps understand the failure mechanism.

Bi-axial behaviours of abraded and rehabilitated FRP decks as anisotropic plates under concentrated wheel loading

For in-service GFRP (glass fibre-reinforced polymer) cellular bridge decks, wheel loads can induce damage of the anti-skid surfacing-to-deck bond, thereby loosening fragments of surfacing that then cause abrasion of the deck’s top flange under further wheel loads. Indeed, over the last 20 years, wheel load-induced damage to the top flanges of FRP decks on the road network has been observed in different countries, after periods in service ranging from a few days to a few years, due to inadequate design. Bonding of uni-directional GFRP panels to the abraded multi-directional flange constitutes a potentially effective rehabilitation strategy, but it also influences the deck’s local wheel-load response by altering the anisotropy of the top flange. The present paper uses an experimental-numerical study to explore this role of anisotropy for both abraded and rehabilitated decks. The experiments captured the top flanges’ peak biaxial strains, using gauges installed on the flange soffits to avoid damage by the wheels. The numerical model captures the morphology of the deck, the actual spread of the tyre load over the contact zone and spatial variations in anisotropy of the abraded or built-up flanges and of the webs. The results show that the uni-axially dominated rehabilitation strategy strongly improves bi-axial response to static wheel loads. The numerical model encouragingly predicts the bi-axial strains for each of the abraded and rehabilitated decks, and reliably predicts the strain reductions due to rehabilitation. Refined meshes along the tyre-loaded local flange span, with coarser meshes in adjacent spans, enable these reasonable predictions of response. It is concluded that top flange soffit gauges installed via ad-hoc tooling inserted through holes in the bottom flange, in tandem with rigorous numerical modelling, constitutes an effective two-pronged approach for elucidating wheel load effects.

Study on effect of dynamic load on rail joint bar by finite element method (FEM)

ABSTRACT The effects of vertical dynamic wheel loading and bolt conditions on rail-end joint bar by using the finite element method (FEM) in terms of vertical displacement, principal and shear stress are investigated. Preliminary results of dynamic load show that variation of either tight/loose-bolted joint bar has the response of rail-end joint varies, the joint bar vertical displacement, principal and shear stresses on the joint bar also vary. The test results show that contact force at the wheel-rail joint bar interface would not change monotonically with the variable train speed and the shear stresses calculated at joint bar significantly lower than the principal stress and stresses of the joint bar for a given speed. The tightly bolted joint bar is strongly recommended because of its high stiffness causing smaller deflection and smaller principal and shear stress on the joint bar can reduce initiation of failure around the joint.

Performance of coir geotextile reinforced subgrade for low volume roads

Reinforcing flexible pavements using different types of geosynthetics is a technique that is widely used to increase the service life, reduce the maintenance costs and, guarantee high performance throughout the service life. This paper presents the insights from combined experimental and numerical analysis conducted on organic soil reinforced with coir geotextiles. A series of small-scale in-box plate load tests were performed to investigate the behavior of coir geotextile reinforced high plastic organic soil under circular loading. Tests were conducted on both homogeneous (sub grade alone) and layered configurations. Two types of commercially available woven coir geotextiles viz. H2M5 and H2M6, were utilized to study the contribution of coir geotextiles when used as reinforcement at the interface of sub-base and subgrade layers in enhancing the strength and stiffness of the low volume road. The primary objective of this exploratory study is to investigate the improvement in the performance of the low volume pavement as a result of the added geotextile reinforcement. The key performance parameters, namely, displacement, stress and strain responses of both reinforced and unreinforced pavement sections are obtained by analyzing the pavement using ABAQUS, which is a software suite for Finite Element Method (FEM) analysis. Test results indicate that the coir geotextile reinforcement substantially improved the performance of high plastic organic subgrade. A maximum reduction of 38% and 24% in vertical strain was observed on top of the subgrade in the case of H2M5 and H2M6 coir geotextile reinforced sections, respectively. Also, a maximum reduction of 30% and 18% in vertical displacement was observed in the case of H2M5 and H2M6 coir reinforced sections, respectively. At an average radial distance of about 1 m from the center of simulated static wheel load, very small displacement and strain value were observed for reinforced sections, relative to the unreinforced sections. Hence, the conclusion is drawn that the H2M5 type of coir geotextile contributes more than the H2M6 type to the structural performance improvement of pavements when used as reinforcement.

The wear mechanisms of diamond grits in grinding of alumina and yttria-stabilized zirconia under different cooling-lubrication schemes

Abrasion is the primary wear mechanism of diamond grits during grinding of advanced ceramics. This work not only highlights some unreported modes of wear of diamond grits but also illustrates and describes their mechanisms while grinding two dissimilar advanced ceramics, viz. alumina and yttria-stabilized zirconia (YSZ). Long-cycle plunge grinding of the ceramics was conducted with single-layer electroplated diamond wheels at 30 m/s and 50 m/s grinding speeds under three different cooling-lubrication schemes – flood cooling (FC), MQL-soluble oil (MQL-SO) and MQL-neat oil (MQL-NO). Radial wheel wear was measured employing indirect profilometry. Diamond grits on the electroplated wheels were observed under SEM before and after grinding to identify and characterize various modes of wear. Severe wheel loading was observed while grinding alumina and YSZ under FC and MQL-SO. Indentation fatigue fracture was found to be the dominant mode of diamond grit wear during alumina grinding under wheel loading conditions. The wear of diamond grits during YSZ grinding was dominated by thermal fatigue fracture at a higher grinding speed of 50 m/s. Thermal degradation of diamond grits was examined with Raman spectroscopy which revealed graphitization of some of the active diamond grits after YSZ grinding under FC and MQL-NO at 50 m/s.

Experimental study on mechanical properties of heavy-haul low-vibration track under train static load.

In this paper, a full-scale model of Low Vibration Track was established and three working conditions were applied to a single bearing block; these include: vertical load at the end of the track slab, combination of horizontal and vertical load at the end of the track slab, and vertical load at the middle of the track slab. By applying four times static wheel load to the full-scale model, the relationship between the stress of the track structure and the load under different working conditions was investigated. The corresponding load values were obtained when the track slab and the bearing block reached the axial tensile strength of the concrete. Through the static load test, the weak position of the track structure was found, and the development trend of the crack was obtained. (1) Obtained the maximum stress of the concrete of the track slab at the corner of the bearing block, the maximal stress of the concrete of the track slab, the stress at the bottom of the bearing block, and the stress at the bottom of the bearing block under different working conditions. (2) The horizontal load of the train increased the force of the track slab concrete at the corners of the bearing block. (3) Compared the strain of different location of the track slab and different working conditions. (4) Observed the positions of slight crack and its development trend appeared on track slabs in different working conditions. (5) For the weak part of the track structure, it can be improved by measures such as increasing the thickness of the end of the track slab and arranging stirrups in the track slab around the support block. The research results provide reference for the design, application and maintenance of Low Vibration Track in the heavy-haul railway tunnel.

Modelling and simulation of effect of missed bolt on rail end joint by fem

ABSTRACT The present study focused on the modelling and simulation of bolted rail joint using the finite element method. The effects of support conditions and missed bolt cases when the load was fixed at first bolt head, on the rail end vertical displacement, stress distribution at the bolt-hole and the upper fillet area under static loading condition are investigated. Preliminary results of the static wheel load showed that when the load is acting at first bolt-hole, the response of the rail-end joint varies, the rail vertical displacement and stresses on the rail upper fillet and stress on the bolt-hole were also varied. Therefore, the rail-end bolt-hole stress reaches its maximum when the wheel is directly above it which causes less stiffness and high deflection around the rail-end joint which showed the same overall trend of the result by other researchers for different loading, rail standard, stiffness and bolts used.

Hierarchical Multiscale Modeling of Tire–Soil Interaction for Off-Road Mobility Simulation

A high-fidelity computational terrain dynamics model plays a crucial role in accurate vehicle mobility performance prediction under various maneuvering scenarios on deformable terrain. Although many computational models have been proposed using either finite element (FE) or discrete element (DE) approaches, phenomenological constitutive assumptions in FE soil models make the modeling of complex granular terrain behavior very difficult and DE soil models are computationally intensive, especially when considering a wide range of terrain. To address the limitations of existing deformable terrain models, this paper presents a hierarchical FE–DE multiscale tire–soil interaction simulation capability that can be integrated in the monolithic multibody dynamics solver for high-fidelity off-road mobility simulation using high-performance computing (HPC) techniques. It is demonstrated that computational cost is substantially lowered by the multiscale soil model as compared to the corresponding pure DE model while maintaining the solution accuracy. The multiscale tire–soil interaction model is validated against the soil bin mobility test data under various wheel load and tire inflation pressure conditions, thereby demonstrating the potential of the proposed method for resolving challenging vehicle-terrain interaction problems.

Use of fiber optic sensing to measure distributed rail strains and determine rail seat forces under a moving train

Rayleigh backscatter fiber optic sensing permits dynamic strains to be measured along an optical fiber with a gauge spacing and temporal resolution sufficient for rail applications. However, this sensing technology is highly sensitive to vibration. A 7.5 m long section of rail was instrumented with optical fiber and strain measurements were recorded during passage of a freight train slowed to 8–11 km/h. This strategy to minimize rail vibration was successful in permitting distributed dynamic rail strains to be measured under freight car loading. The measured rail strains were used to determine the rail shear forces, which were then used with the static wheel loads to determine the rail seat load for 14 consecutive sleepers as the train passed over the field monitoring site. These data were then combined with measurements of dynamic rail displacement captured using digital image correlation to infer the rail seat load–deflection relationships for individual sleepers. These relationships were observed to provide significantly more detailed information about unsupported voids and the sleeper contact stiffnesses than the traditional consideration of the relationship between applied load and rail deflection and highlights how track behavior at a monitored location can be dependent on the conditions and behavior of neighbouring sleeper.