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The fatigue crack growth behavior of friction stir welded joints of AZ31 Mg alloy is investigated for three different notch locations. The extended finite element method based simulation is developed to capture the effect of stir zone on fatigue crack growth behavior. The notch locations with asymmetric material domain experience an asymmetric stress field, which leads to crack path deviation from the orthogonal direction to the applied force. This leads to a longer crack path. The near-tip stress field from the simulation enhances the understanding of unusual crack path. The experimental results including crack path trajectories from experiments compare well against the numerical predictions. [ABSTRACT FROM AUTHOR]

Abstract Sustainable growth of the lithium-ion battery (LIB) industry requires a safe supply of raw materials and proper end-of-life management for products. The lack of research on domestic critical raw materials and on management systems has limited the formulation of relevant policies for LIB-related industries. Here, a critical raw material (CRM) evaluation model was developed to identify the criticality associated with the supply risk (SR) and economic importance (EI) of different materials for the Chinese LIB industry. Dynamic materials flow analyses of the relevant critical materials were carried out by integrating a trade-linked model. Criticality analysis identifies the importance of different materials and optimizes the subsequent materials flow analysis. The results showed that the in-use stocks share large portions of material flow for Li, Ni, Co and graphite and further suggests that the market will not be saturated before 2025. For the end-of-life stage, less than 40 wt% of the materials in LIBs can be recycled under the current scheme of materials flow in China; this finding puts significant pressure on proper waste management. Consequently, it is very important to identify effective methods for utilizing the growing amount of waste materials and to provide a resource supplement for the Chinese LIB industry. This research provides guidelines for improving management strategies relevant to the critical materials in the LIB industry, for increasing resource efficiency, and for managing critical resources. Graphical abstract Image 1 Highlights • MFA for multiple elements in LIB industry is still scattered. • A CRMs evaluation system was proposed to optimize the further MFA. • Sankey diagrams of Li, Co, Ni and C reveal their status in Chinese LIB industry. • The stock and obsolete amount from 2012 to 2025 were estimated and forecasted. [ABSTRACT FROM AUTHOR]

End-of-life light emitting diode (LED) associated with its electronic product is a new type of electronic waste (E-waste) and contains considerable amounts of valuable and hazardous metals. Although the quantity of a single LED is small, the total number of end-of-life LEDs is extremely significant that requires proper management and recycling from both resource and environmental points of view. Particularly, metals recycling from electronic waste has been considered as a preferred option to ensure sustainable supply of critical materials. In this research, it demonstrates a methodology to evaluate the criticality and recyclability of various types of end-of-life LEDs. Two factors, i.e. the resource index and technology index, were introduced into identifying the criticality of different types of waste LEDs, which indicates the potentials for effective metals recycling. Furthermore, combined statistical entropy and grading, the recyclability is assessed to identify the viability for metals recycling from different types of end-of-life LEDs. The results of the proposed evaluation methodology suggest that green/high luminous intensity LED exhibits significant potential for metal recycling and blue/high luminous intensity LED exhibits the lowest recycling difficulty. The aims of the research are expected to assist manufacturers and policy-makers improving the recycling effectiveness of waste LEDs especially in the metals recycling stage and developing effective waste management systems and strategies in the end-of-life stage. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI), induced by impact of an object with the head, is a major health problem worldwide. Rats are a well-established animal analogue for study of TBI and the weightdrop impact-acceleration (WDIA) method is a well-established model in rats for creating diffuse TBI,the most common form of TBI seen in humans. However, little is known of the biomechanics of the WDIA method and, to address this, we have developed a four-degrees-of-freedom multi-body mass-spring-damper model for the WDIA test in rats. An analytical expression of the maximum skull acceleration, one of the important head injury predictor, was derived and it shows that the maximum skull acceleration is proportional to the impact velocity but independent of the impactor mass. Furthermore, a dimensional analysis disclosed that the maximum force on the brain and maximum relative displacement between brain and skull are also linearly proportional to impact velocity. Additionally, the effects of the impactor mass were examined through a parametric study from the developed multi-body dynamics model. It was found that increasing impactor mass increased these two brain injury predictors. [ABSTRACT FROM AUTHOR]

A shear-lag model with a cohesive fibre–matrix interface has been developed for the analysis of stress transfer between the fibre and the matrix in fibre-reinforced composites in this paper. A bilinear cohesive damage evolution law is used to describe the fibre–matrix interface behaviour. The governing equations for the interfacial shear stress and the axial stress in the fibre are derived. Accurate analytical solutions are obtained when the fibre–matrix interface is in the initial linear elastic deformation regime. When debonding occurs, interfacial damage and softening are modelled by superposing two elastic stress systems and satisfying the damage evolution law at both ends of the damage process zone, and approximate analytical solutions are obtained. The stress distribution and evolution during the fibre pull-out, the maximum pull-out force and the pull-out curve have been analysed using a shear strength-based debonding criterion. Analytical expressions for the maximum fibre pull-out force and its limit as the embedded fibre length approaches infinity are obtained. In addition, the new function proposed for describing the radial distribution of the shear stress in the matrix fixes the problem of zero shear-lag parameter when b / a approaches infinity, enabling the shear-lag analysis to deal with low fibre volume fractions. Generally, the analytical solutions compare satisfactorily well to the cohesive finite element calculations and experimental data in the literature. [ABSTRACT FROM AUTHOR]

Abstract: The indentation test is a popular experimental method to measure a material’s mechanical properties such as elastic modulus and hardness, and the Oliver–Pharr method is commonly used in commercial indentation instruments to obtain these two quantities. To apply the Oliver–Pharr method correctly in all of these cases, it is essential to know the limitations of this method. The present study focuses on the applicability of the Oliver–Pharr method to measure the mechanical properties of particles in composites. The finite element method is used to undertake virtual indentation tests on a particle embedded in a matrix. In our numerical studies, the indentation “pile-up” phenomenon is generally observed in our numerical case studies, which indicates that the contact area used for predicting the elastic modulus should be measured directly, not be estimated from the indentation curve. The Oliver–Pharr method based on the real contact area is applied to estimate the elastic modulus of the particles by using the indentation curve from the numerical simulation, with the estimated elastic modulus being compared with the input value. Applying the real contact area value (not the one predicted from the indentation curve) we show that the Oliver–Pharr method can still be applied to measure the elastic modulus of the particle with sufficient accuracy if the indentation depth is smaller than the particle-dominated depth, a value defined in this work. The influences of the matrix and particle properties on the particle-dominated depth are studied using a dimensional analysis and parametric study. Our results provide guidelines to allow the practical application of the Oliver–Pharr method to measure the elastic modulus of particles in composites. This could be particularly important where particles are formed in situ in a matrix (as opposed to being preformed and subsequently incorporated in a matrix), or when the modulus of individual performed particles is required such as for subsequent modelling, but the modulus of individual material particles (or its material) cannot readily be determined. [Copyright &y& Elsevier]

Abstract: In sheet metal stamping, it is known that wear is unevenly distributed over the die radius and that multiple wear mechanisms may occur simultaneously. However, there has been little or no work that details the types of wear mechanisms, and quantifies the locations at which they occur. Furthermore, the link between recently identified time-dependent contact conditions and the wear response is currently unknown. An experimental study is presented in this paper to examine the location, type and severity of wear that occurs over the die radius during a typical sheet metal stamping process. It is found that the wear over the die radius consists of a combination of ploughing and galling mechanisms. The relative severity of the ploughing mechanism is divided into two distinct zones on the die radius, which correlate well with the contact pressure and sliding distance behavior predicted in our recently published numerical study. The galling mechanism results in failure of the stamping process and is, therefore, critical to the overall tool wear response. Our analysis indicates that the severe contact pressure/small sliding distance conditions, which occur during the initial stage of the process, cause the galling behavior observed over the radius. Therefore, it is concluded that the overall tool wear response and tool life is primarily dependent on the initial transient stage of the stamping process. [Copyright &y& Elsevier]

Abstract: The application of the indentation method to measure the elastic modulus of particles embedded in a composite is theoretically investigated in this paper by finite element simulation. The Oliver–Pharr method, which is widely used in commercial nanoindentation instruments, is used to probe the elastic modulus of the particle from the simulated indentation curve. The predicted elastic modulus is then compared with the inputted value. Two cases are studied, that of a stiff particle embedded in a soft matrix and a soft particle embedded in a stiff matrix. In both of these cases, there exists a particle-dominated depth. If the indentation depth lies within this particle-dominated depth, the Oliver–Pharr method is able to be applied to measure the particle’s elastic modulus with sufficient accuracy if the real contact area is used. This could lead to an experimentally-convenient method of determining the primary properties of individual particle, providing they can be well dispersed in the polymeric matrix. [Copyright &y& Elsevier]

A recently published finite element (FE) head model is modified to consider the viscoelasticity of the meninges, the spongy and compact bone in the skull. The cerebrospinal fluid (CSF) is simulated explicitly as a hydrostatic fluid by using a surface-based fluid modelling method, which allows fluid and structure interaction. It is found that the modified model yields smoother pressure responses in a head impact simulation. The baseline model underestimated the peak von Mises stress in the brain by 15% and the peak principal stress in the skull by 33%. The increase in the maximum principal stress in the skull is mainly caused by the updation of the material's viscoelasticity, and the change in the maximum von Mises stress in the brain is mainly caused by the improvement of the CSF simulation. The study shows that the viscoelasticity of the head tissue should be considered, and that the CSF should be modelled as a fluid, when using FE analysis to study head injury due to impact. [ABSTRACT FROM AUTHOR]

Abstract: Porous titanium is a promising orthopedic implant material. As a potential use in total hip replacement, the effect of a porous titanium femoral prosthesis on bone remodeling is investigated in this paper. The stress and strain fields of a post-operative femur with a hip replacement are calculated by applying the three-dimensional finite element method. The effect of the implant material on the bone remodeling is evaluated by analyzing the loss of bone density following a strain magnitude based bone remodeling theory. Different implant materials, including currently used solid cobalt–chrome and solid titanium, potential porous titanium with different porosities, are considered in this study. This investigation confirms that bone loss around the implant strongly depends on the value of the elastic modulus of the prosthesis. There will be a sharp drop of the volume of the bone with density loss if a cobalt–chrome implant is replaced by a porous titanium implant. The numerical results show that both of the bone volume with density loss and the bone density loss rate decrease linearly with the increase of the porosity. However, increasing porosity will reduce the strength of porous titanium. With regard to material design for porous titanium-based femoral prosthesis, stress analysis is required to meet the strength requirement. [Copyright &y& Elsevier]

Abstract: Metallic foams are a new class of functional materials. They have found their applications as sandwich cores in lightweight structures and as implant materials in bioengineering. To characterize the mechanical properties of these materials becomes an interesting and relevant research topic. In the mean time, indentation method has been well accepted as a simple and effective way to measure the mechanical properties of solid materials. We believe that it is possible to study the averaged mechanical properties of a metallic foam from a spherical indentation test. In this paper, theoretical investigation to understand the spherical indentation responses of metallic foams is presented. Based on the dimensional analysis, several scaling relationships in the indentation of metallic foams with a spherical indenter are obtained. Numerical results from the finite element simulations are used to examine the dependence of the indentation response on the basic material parameters, such as the porosity, the work hardening exponent and the shape factor, which characterizes the plastic deformation of metallic foams due to hydrostatic loading. Our numerical results show that the maximum indentation force has a linear relationship with the indentation depth for different shape factor values. It is therefore proposed to calibrate the shape factor value from the slope of the maximum indentation force versus the indentation depth from a spherical indentation test, instead of a complicated hydrostatic loading test. We also find that the spherical indentation hardness varies about 11% within the examined indentation depths. The range of the ratio of the hardness to the yield strength of metallic foams is from 2.17 to 2.95, which is different from that of solid materials. Our study provides the basis for applying a simple spherical indentation test to investigate the mechanical properties of metallic foams. [Copyright &y& Elsevier]

Abstract: This paper directly examines the contact sliding distance experienced during a typical sheet metal stamping process—an area that has largely been neglected in the literature. A method to numerically quantify the sliding distance is proposed. The sliding distance predicted from this method, and the contact pressure obtained from numerical simulation, allow the recently identified time-dependent contact conditions on the die and blank surfaces to be completely characterized. Consequently, a new insight into the wear/galling that occurs at the die radius in sheet metal stamping is gained. The results show that the region close to zero degrees on the die radius is likely to experience the most wear, with the identified transient stage contributing to a large proportion of the total wear. Additionally, the region on the blank surface often observed to be heavily burnished – the die impact line – is estimated to experience the highest wear severity due to the transient contact conditions. The proposed method to numerically quantify the sliding contact conditions can be applied as a general approach to study any other two-body sliding contact situations. [Copyright &y& Elsevier]

The mechanical response of spherical indentation of superelastic shape memory alloys (SMAs) was theoretically studied in this paper. Firstly, the friction effect was examined. It was found that the friction influence is negligibly small. Secondly, the influence of the elasticity of the indenter was investigated. Numerical results indicate that this influence can not be neglected as long as the indentation depth is not very small. After that, this paper focused on the effect of transformation volume contraction. Our results show that the transformation volume contraction due to forward martensitic transformation can reduce the maximum indentation force and the spherical indentation hardness. These research results enhance our understanding of the spherical indentation responses, including the hardness of the smart material SMAs. [ABSTRACT FROM AUTHOR]

Abstract: For a given sheet metal forming process, an accurate determination of the contact pressure distribution is an essential step towards the estimation of tool life. This investigation utilizes finite element (FE) analysis to model and explain the evolution and distribution of contact pressure over the die radius, throughout the duration of a channel forming process. It was found that a typical two-peak steady-state contact pressure response exists for the majority of the process. However, this was preceded by an initial transient response, characterized by extremely large and localized contact pressures, which were more than double the magnitude of the steady-state peak pressure. The validity of the predicted contact pressure behavior was assessed via detailed numerical analysis and by examining the wear response of an experimental stamping operation. The experimental results revealed that the high contact pressure zones of the transient response corresponded to a severe galling wear mechanism. Therefore, the transient response may be of primary significance to the tool wear response; thus questioning the applicability of traditional bending-under-tension wear tests for sheet metal stamping processes. Finally, a parametric study was conducted, examining the influence of the major process parameters on the steady-state and peak transient contact pressures, using the developed FE model. It was found that the bend ratio and the blank material ultimate tensile strength had the most influence on the peak contact pressures. The main process-related parameters, friction coefficient and blank holder force, were found to have only a minor influence. [Copyright &y& Elsevier]

Abstract: This paper presents an experimental investigation on mode I delamination of z-pinned double-cantilever-beams (DCB) and associate z-pin bridging mechanisms. Tests were performed with three types of samples: big-pin with an areal density of 2%, small-pin with an areal density of 2% and small-pin with an areal density of 0.5%. The loading rates for each type of samples were set at 1mm/min and 100mm/min. Comparison of fracture load under different loading rates shows the rate effects on delamination crack opening and delamination growth. Optical micrographs of z-pins after pullout were also presented to identify the bridging mechanisms of z-pins under different loading rates. [Copyright &y& Elsevier]

Abstract: Dimensional analysis and the finite element method are applied in this paper to study spherical indentation of superelastic shape memory alloys. The scaling relationships derived from dimensional analysis bridge the indentation response and the mechanical properties of a superelastic shape memory alloy. Several key variables of a superelastic indentation curve are revealed and examined. We prove that the bifurcation force in a superelastic indentation curve only relies on the forward transformation stress and the elastic properties of the initial austenite; and the return force in a superelastic indentation curve only relies on the reverse transformation stress and the elastic properties of the initial austenite. Furthermore, the dimensionless functions to determine the bifurcation force and the return force are proved to be identical. These results not only enhance our understanding of spherical indentation of superelastic shape memory alloys, but also provide the theoretical basis for developing a practicable method to calibrate the mechanical properties of a superelastic material from the spherical indentation test. [Copyright &y& Elsevier]

Abstract: Recent experimental research indicates that superelastic shape memory alloy nickel–titanium (NiTi) is superior to stainless steel against wear and could be applied in tribological engineering. It is believed that the super wear resistance of shape memory alloys is mainly due to the recovery of the superelastic deformation. Our recent wear study indicates that wear rate is very sensitive to the maximum contact pressure. In the present investigation, which involves applying Hertz contact theory and the finite element method, the wear behaviour of shape memory alloys is examined against that of stainless steels through analyzing the maximum contact pressure and the plastic deformation. Our investigation indicates that the contribution of superelasticity to the high wear resistance of NiTi is directly linked to the low transformation stress and the large recoverable transformation strain. Furthermore, the low Young''s modulus of this alloy also plays an important role to reduce the maximum contact pressure and therefore reduce the wear rate. Additionally, the high plastic yield strength of transformed martensite NiTi enhances its wear resistance further. [Copyright &y& Elsevier]

Abstract: Using dimensional analysis and the finite element method, the spherical indentation hardness of shape memory alloys (SMAs) is investigated. The scaling relationship between the hardness and the mechanical properties of a SMA, such as the forward transformation stress, the maximum transformation strain magnitude, has been derived. Numerical results demonstrated that the hardness increases with the indentation depth but there is no three-fold relationship between the hardness and the forward transformation stress. Increasing the maximum transformation strain magnitude would reduce the hardness of the material. These research results enhance our understanding of the hardness from the spherical indentation of SMAs. [Copyright &y& Elsevier]

This paper presents an experimental study on the evaluation of bridging law for a z-pin. The relationship between the z-pin bridging force and its displacement was measured by z-pin pullout tests. The tests were carried out using three types of samples with: single small pin; 3×3 small-pins (three columns×three rows) and 3×3 big-pins. For 3×3 small-pins samples, a typical pullout curve with initial bonding, debonding and frictional sliding was obtained. A high peak value of the debonding force was reached before z-pin debonding started. After debonding was initiated, the pullout force dropped rapidly to a lower value, the pins were then pulled out steadily against friction. However, for samples with 3×3 big-pins, it was difficult to discern the peak debonding force. The major results of this study are expected to provide a better physical understanding of the mechanics and mechanisms of z-pin bridging, aside from an efficient and accurate methodology to measure the crack-bridging law. [Copyright &y& Elsevier]

Mode II delamination toughness of z-pin reinforced composite laminates is investigated using finite element (FE) method. The z-pin pullout process is simulated by the deformation and breakage of non-linear springs. A critical shear stress criterion based on linear elastic fracture mechanics is used to simulate crack growth in an end-notched-flexure (ENF) beam made of z-pinned laminates. The mode II toughness is quantified by the potential energy release rate calculated using the contour integral method. This FE model is verified for an unpinned ENF composite beam. Numerical results obtained indicate that z-pins can significantly increase the mode II delamination toughness of composite laminate. The effects of design variables on the toughness enhancement of z-pinned laminates are also studied, which provides an important technological base and useful data to optimize and improve the z-pinning technique. [Copyright &y& Elsevier]

Stimulated by recent experimental results on superelastic NiTi shape memory alloy, a theoretical study is carried out to quantify the effect of plasticity on stress-induced martensite transformation, using a constitutive model that combines phase transformation and plasticity. A constraint equation is introduced to quantify the phenomenon of the stabilisation of plasticity on stress-induced martensite. The stabilised martensite volume fraction is determined by the equivalent plastic strain. The transformation constitutive model is adopted from a generalised plastic model with Drucker–Prager type phase transformation functions, which are pressure sensitive, while the plasticity is described by the von Mises isotropic hardening model. The martensite volume fraction is chosen as the internal variable to represent the transformation state and it is determined by the consistency transformation condition. An approach to calibrate model parameters from uniaxial tensile tests is explored, as well as the issue of elastic mismatch between austenite and martensite is discussed. Based on the proposed constitutive model, the influence of hydrostatic stress on transformation is examined. As an example of application, this new constitutive model is employed to numerically study the transformation field and the plastic deformation field near a crack tip. [Copyright &y& Elsevier]

A finite element (FE) model is developed to investigate mode I delamination toughness of z-pin reinforced composite laminates. The z-pin pullout process is simulated by the deformation of a set of non-linear springs. A critical crack opening displacement (COD) criterion is used to simulate crack growth in a double-cantilever-beam (DCB) made of z-pinned laminates. The toughness of the structure is quantified by the energy release rate, which is calculated using the contour integral method. The FE model is verified for both unpinned and z-pinned laminates. Predicted loading forces from FE analysis are compared to available test data. Good agreement is achieved. Our numerical results indicate that z-pins can greatly increase the mode I delamination toughness of the composite laminates. The influence of design parameters on the toughness enhancement of z-pinned laminates is also investigated, which provides important information to optimise and improve the z-pinning technique. [Copyright &y& Elsevier]

Abstract: The indentation slope curve from a spherical indentation on elastic-plastic materials is examined. By comparing it with that of an linear elastic material of the same elastic properties, we found that the start point of plastic yielding for an elastic-plastic material can be easily located from the indentation slope curve. Based on this analysis, a simple but effective method is proposed to measure the plastic yield stress of very small samples from a spherical nano-indentation slope curve. [Copyright &y& Elsevier]

With the rapid development of the lithium-ion battery (LIB) industry, the demand for core valuable elements in LIB has increased dramatically. A safe supply of corresponding metals is crucial to ensure the industry's sustainability. However, quantitative evaluation to reveal the supply risk including criticality of LIBs in China is still not available. In this regard, criticality analysis was carried out to identify the importance of a specific metal in the current LIBs supply chain of raw materials. Subsequently, a comprehensive methodology to evaluate supply sustainability is established in this research by considering the combined effects of material supply, economic fluctuations, and technology innovation in the time frame from 2015 to 2030. An integrated index called Chinese supply resilience is introduced, indicating that a low Chinese supply resilience has a high possibility of supply shortage of the corresponding metal while a high resilience level represents minor supply risk. The results show that insufficient material supply has already induced a severe shortage for lithium (Li) and cobalt (Co). Specifically, Chinese supply resilience of lithium moves from the threshold to the low resilience zone, whereas that for cobalt remains in the low area, both implying a high risk of supply shortage. Furthermore, three appropriate mitigation measures, that is, recycling of spent LIBs, substitution of raw materials, and an increase in domestic raw materials production are considered. Recycling demonstrates the most effective solution to alleviate the potential supply risk of corresponding materials. With this research, it may promote management efficiency on end-of-life LIBs for policy makers. Image 1 • The index of Chinese supply resilience is used to evaluate supply risk of materials. • Supply resilience for Li moves from the threshold to the low-resilience zone. • Supply resilience for Co remains in the low-resilience zone. • Effect of material supply, economy and technology innovation is analyzed. • Scenario analysis considering recycling, substitution and production is conducted. [ABSTRACT FROM AUTHOR]

Railway in-train forces are an essential element in assessing multiple aspects of rolling stocks. Conventional methods for obtaining the forces can be time-consuming and require significant investment in manpower and domain expertise, while only gathering the force data for specific service conditions one at a time. However, automatic train operation (ATO) systems can measure real-time information for trains and tracks by on-board and trackside devices, which could provide an opportunity for in-train forces monitoring. This paper presents a data-driven approach that uses ATO-measured data and a neural network model to monitor in-train forces under service conditions. To develop this approach, longitudinal train dynamics simulations (LTSs) for a freight train were conducted to establish the relationship between ATO measurements and in-train forces on specific couplers, which was embedded in a large amount of training data. After that, a specially developed self-attention-based causal convolutional neural network (SA-CNN) was employed to learn the underlying relationship and estimate the in-train force histories considering temporal dependencies. The comparative evaluation between the SA-CNN against four alternative neural network models revealed that the SA-CNN exhibits a slightly higher level of accuracy. Furthermore, the generalisation capability of the well-trained SA-CNN model was confirmed by numerical LTSs under four different service conditions. The results indicated that the data-driven approach has superior compatibility for arbitrarily combined inputs with significantly reduced computational time compared to LTSs. This approach holds the potential for achieving reliable in-situ monitoring of railway in-train forces, which is beneficial to both in-train force-related research and industrial applications. [ABSTRACT FROM AUTHOR]

Both the mean contact force difference and the standard deviation of the contact force were minimised in the presented optimised design of a pantograph–catenary system for the purposes of improving of the current collection quality and the reduction of the contact wear. The non-dominated sorting genetic algorithm-II (NSGA-II) was applied to optimise the pantograph–catenary interaction system. The adopted NSGA-II algorithm was improved by avoiding repetition of FEM simulations with the duplicated input parameters and retaining only one of the duplicated results for the next generation selection. Either the catenary or the pantograph can be optimised individually by using the proposed versatile approach. In this research, the design optimisation of the catenary system was conducted first. After that, the pantograph was further optimised based on the optimised design of the catenary system. A case study indicated that the standard deviation of the contact force was reduced by 33.4% in the optimised catenary design and 39% in the optimised pantograph design, and the contact force differences were reduced by 98.3% and 99.9% in the optimised catenary design and the optimised pantograph design, respectively. Highlights Both the standard deviation of the contact force and the difference between the actual mean contact force and the ideal mean contact force are minimised in the optimisation design of a pantograph–catenary system. Either the catenary or the pantograph can be optimised separately by using the proposed versatile approach. Non-dominated Sorting Genetic Algorithm-II (NSGA-II) was improved by avoiding repetition of finite element method simulations with the same input parameter combinations and retaining only one of the same results for the next generation selection. A case study indicates that the standard deviation of the contact force can be reduced by 33.4% in the optimised catenary design and 39% in the optimised pantograph design, and the contact force difference can be reduced by 98.3% and 99.9% in the optimised catenary design and the optimised pantograph design, respectively. [ABSTRACT FROM AUTHOR]

The whole industry chain of lithium-ion batteries (LIBs) has gained worldwide attention because of their important role in energy storage and electric vehicles. The purpose of this research is to systematically overview the evaluation methodologies for LIBs industry. Under this basis, carbon emission intensity in the whole industry is understood, and the development trend can be presumed. Herein, an efficient zero-pollution, low-carbon process, and green manufacturing evaluation methodology for the whole LIBs industry chain are proposed. To improve the comprehensive evaluation efficiency, the battery structure, design parameters, material composition in the production process and material source, recycling methods and battery types in the recovery process are considered. The investigation shows that environmental impact can mainly be attributed to the production and use stages, which reached 12–15% and 80% respectively in the whole industry chain. The average profit of recycling waste batteries is more than 10%, which is conductive to the development of recycling industry. Based on this situation, a 4 A multi-angle comprehensive evaluation system, considering environmental impact assessment, resource criticality assessment, economic analysis and materials flow analysis, can be established by implementing the developmental mode of resource cyclic utilization. It is expected that this research could provide a guideline for the comprehensive evaluation for LIBs and stimulate further discussions on sustainable development and low-carbon technology improvement. [Display omitted] • A number of sustainability evaluation for LIBs are systematically overviewed. • Carbon emission intensity and develop trend in the whole industry is understood. • The green manufacturing is topping the list for research requiring profound. • A 4 A multi-angle comprehensive evaluation system is established. [ABSTRACT FROM AUTHOR]

Abstract The effects of different cladding materials, processing parameters and heating regimes on the underlying microstructural features and mechanical properties of laser-cladded premium rails were investigated by using a hypereutectoid rail grade as a substrate, which is extensively used in heavy-haul rail systems. Cladding materials of 410L, 420SS, Stellite 6 and Stellite 21 with single and double depositions were considered for the comparative study of different cladding materials and processing parameters. To ensure the constant thickness of the claddings for comparison purposes, transverse speed and powder feed rate were modified concurrently in the ranges of 1000–1200 mm/min and 3–4 RPM, respectively. Two heating conditions, i.e. preheating only (HTA) and a combination (HTB) of preheating and post weld heat treatment (PWHT) were applied after the preferable parameters for each cladding material were obtained. The most suitable cladding material for rail-wheel contact was established by assessing all crucial aspects, i.e. surface defects, hardness, microstructural and mechanical properties. Process parameters for each considered cladding material were determined to achieve no surface defects. For cladding layers, application of HTA was not able to significantly modify the microstructures of the deposits, whereas HTB was observed to cause severe cracks in Co-base alloys, i.e. Stellite 6 and Stellite 21. In the heat affected zones (HAZs), irrespective of the cladding materials, the formation of untempered martensite was not avoided by the application of preheating at 350 °C. Consequentially, cracking in the HAZ was observed. An uncracked and desirable microstructure in the HAZs was established using HTB, regardless of the depositing materials. The addition of a second layer did not change the thickness of the HAZs but refined the HAZ’s microstructures. Shear punch testing (SPT) and Vickers hardness testing were utilized to characterize mechanical properties for the considered cladding materials and good correlations with the obtained microstructural morphologies were shown. [ABSTRACT FROM AUTHOR]

The impacts of preheating conditions and carbon dilution on the microstructural and mechanical properties of laser cladded rails using single and double cladding layers have been investigated for a hypereutectoid steel grades typically used under heavy haul conditions. The microstructures in the HAZ showed that formation of martensite, which has a detrimental effect on behaviour in wheel-rail contact, was successfully inhibited by increasing the length of the preheated region using a preheating temperature of 350 °C. Dilution of carbon from the hypereutectoid substrate was observed and its effect on the microstructures of the 410L ferritic stainless-steel deposits was investigated. The formation of ferrite in the 410L cladding layers was attributed to the very low carbon content, and no carbide formation was observed on boundaries of the ferritic grains. The thickness of dilution band was determined to be approximately equal to the thickness of the first cladding layer. Texture measurement obtained by EBSD showed a random trend owing to the formation of martensite in diluted bands. Strong solidification fibre texture was developed for double deposition, particularly in the second deposit. Mechanical characterization of the 410L deposits undertaken in terms of Vickers microhardness, shear and tensile yield strengths, and ultimate tensile and shear strengths were correlated with the observed microstructural morphologies. [ABSTRACT FROM AUTHOR]

In this study, the effects of cladding direction, preheating and post heat treatment on microstructural and mechanical properties of laser cladded rail repairs are presented. Laser cladding of a premium hypereutectoid rails grade with 410L stainless steel powder were conducted using a fibre laser gun with a powder feeder. Two different cladding directions and different heat treatment regimes were investigated. An excellent microstructural consistency was established across the railhead and its heat affected zone (HAZ) by changing cladding direction and using a heat treatment consisting of pre-heating and post-heating. The microstructure of the cladding layer and HAZ were characterized by optical microscopy and SEM. Phase identification and distribution were investigated by using XRD, EDS, and EBSD. Indications of the mechanical and tribological performance of the cladding layer in wheel-rail contact were obtained via shear punch tests and Vickers indentation, which demonstrated great correlation with the obtained microstructure. [ABSTRACT FROM AUTHOR]

A multiple crack weight technique with a level set method is proposed to model multiple cracks using a coarse meshfree nodal discretization. A new level-set structure is presented to handle multiple cracks and their propagation using the maximum tangential principal stress criterion. The level sets are updated with respect to the new crack tip positions. The problem of modelling interacting cracks in isotropic and bi-materials is studied using a new variant of the element-free Galerkin method. The stress intensity factors (SIFs) and energy release rates for interacting cracks in isotropic and homogenous materials, including a crack at a bi-material interface are determined using the standard interaction integral. Case studies involving crack-crack interactions, doubly and triply kinked cracks are analysed to demonstrate the simplicity and the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Manufacturing and maintenance procedures in the railway industry regularly implement welding and metal deposition operations to produce joints, coatings and repair structures. During these processes, residual stresses arise through the generation of heat affected zones and plastic deformation. This makes accurate measurements of the internal stresses a critical aspect of manufacturing, monitoring, repair and model validation in the develop new metallic coating and joining technologies. Selection of an appropriate residual stress measurement method has many important factors including component size, resolution and the magnitude and location of internal stresses, often resulting in a combination of techniques required to obtain complete assessment of the stress state. This paper offers a review of residual stress measurement techniques for railway components including rail joints and coatings through comparison of destructive and non-destructive approaches, their measurement capabilities, benefits and limitations. A comprehensive discussion of different applications is provided with a summary of facilities available to both research and industry. [ABSTRACT FROM AUTHOR]

Tram or light rail systems are heavily relied upon for passenger transit; however, low-carbon steel grades commonly used in special trackwork, such as in switches, are prone to wear, rolling contact fatigue (RCF), and deformation under cyclic wheel–rail contact. To address this, laser cladding can be used to apply a metal coating to protect the underlying substrate and rebuild the worn rail profiles. Laser cladding may also be applied to remove cracking by rebuilding the rail head. The tribological characteristics of light rail components after laser cladding with Stellite 6 and a newly developed martensitic stainless steel were investigated, using roller-on-disc wear testing. Analysis of the microstructure, mechanical properties, and wear performance was undertaken to develop a comprehensive understanding of the influence of the laser cladding type on the wear and surface fatigue performance. Both cladding alloys significantly improved the tribological performance. These findings were compared to those for a laser cladded hypereutectoid rail type (reported in our previous study). It was found that laser cladding with a suitable alloy was an effective technique for improving the tribological properties, increasing the wear resistance, and increasing the retardation of cracking on both substrates. These findings suggest laser cladding may be used to repair light rail components, and this technique can be optimized to suit different rail grades. This makes laser cladding a flexible and versatile maintenance strategy, in both coating and repair applications, to prolong the operational lifetime of critical components for the railway industry. [ABSTRACT FROM AUTHOR]

Manufacturing of chips and their associated products is a complex and multi-step process where evaluation on the materials and environmental efficiencies is difficult, and a typical life cycle assessment cannot fulfil the role. In this research, a multiple evaluation scheme in view of green manufacturing is developed by combining critical evaluation, mass flow analysis and environmental impact assessment, in order to define the green degree for chips and lamps production of light-emitting diodes (LED). Mass and energy flow are identified with a subsequent critical evaluation for the whole process to determine the importance of 160 kinds of substances, energies, waters, pollutants, and procedures. In 96 kinds of substances, the organics and metal contained substances have higher criticality and accounting for 33.49% and 56.54%, respectively. To understand the effects of critical pollutants, a comprehensive environmental assessment factor (CEA) is then implemented, and waste water in chip preparation section has larger CEA value. As a result, ten green manufacturing level is defined through a grading decision function, and LED filament lamp reaches a higher manufacturing level than surface-mounted device (SMD) based LED lamp. By defining three scenarios, the manufacturing level of largest environmental effect scenarios is 7, reflecting the CEA of the pollutants is the most critical parameter. With this evaluation system, the green manufacturing level of one manufacturing section or different manufacturing processes can be evaluated, which can guide the identification and classification of LED lamps and other products. [Display omitted] • A multiple evaluation scheme in view of green manufacturing was developed. • Critical evaluation, mass flow analysis and environmental assessment were combined. • The green manufacturing level of LED filament lamp is higher than SMD LED lamp. • Environmental impact of the pollutants largely affects the green level of LED lamp. [ABSTRACT FROM AUTHOR]

The development of a laser cladding repair strategy is critical for the continued growth of heavy-haul railway networks. Premium hypereutectoid rails have undergone laser cladding using a new martensitic stainless-steel alloy, 415SS, developed for high carbon rails after standard cladding metals were found to be incompatible. Non-destructive neutron diffraction techniques were used to measure the residual stress in different layers generated across a dissimilar metal joint during laser cladding. The internal stress distribution across the cladding, heat-affected zone (HAZ), and substrate was measured in the untempered rail, after 350 °C and 540 °C heat treatment procedures and two surface grinding operations. The martensitic 415SS depositions produce compressive stress in the cladding, regardless of tempering procedures, which may inhibit fatigue crack propagation whilst grinding operations locally relive surface stress. Balancing tensile stresses were recorded below the fusion boundary in the HAZ due to thermal gradients altering the microstructure. The combination of 540 °C tempering and 0.5 mm surface layer removal produced a desirable combination of compression in the cladding deposition with significantly reduced tensile stresses in the HAZ. A comparison with the current literature shows that this alloy achieves a unique combination of desirable hardness, low tensile stress, and compression in the cladding layer. Data obtained during strain scanning has been used to determine the location of microstructural changes at the fusion boundary and HAZ through correlation of the stress, strain, full width at half maximum (FWHM), and intensity profiles. Therefore, neutron diffraction can be used for both the accurate measurement of internal residual stress and to obtain microstructural information of a metallurgical join non-destructively. [ABSTRACT FROM AUTHOR]

In powder-based additive manufacturing, the unused powder must be removed after printing. Topology optimization has been applied to designs for additive manufacturing, which may lead to designs with enclosed voids, where the powder will be trapped inside during printing. A topology optimization method incorporating a powder removal passageway is developed to avoid the powder being trapped inside the structure. The passageway is generated by connecting the entrance, all voids, and the exit sequentially. Each void is limited to have only one pair of inlet and outlet to guarantee a single-path flow to facilitate powder removal after the additive manufacturing. The path of the passageway is optimized to minimize its influence on structural stiffness. The proposed optimization method was applied to two practical case studies where the powder removal passageways were generated successfully. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT) reinforced polymeric composites provide a promising future in structural engineering. To understand the bridging effect of CNT in the events of the fracture of CNT reinforced composites, the finite element method was applied to simulate a single CNT pullout from a polymeric matrix using cohesive zone modelling. The numerical results indicate that the debonding force during the CNT pullout increases almost linearly with the interfacial crack initiation shear stress. Specific pullout energy increases with the CNT embedded length, while it is independent of the CNT radius. In addition, a saturated debonding force exists corresponding to a critical CNT embedded length. A parametric study shows that a higher saturated debonding force can be achieved if the CNT has a larger radius or if the CNT/matrix has a stronger interfacial bonding. The critical CNT embedded length decreases with the increase of the interfacial crack initiation shear stress. [ABSTRACT FROM AUTHOR]

The finite element method was used to simulate indentation tests on a particle embedded in a matrix, to investigate the influence of the properties of the particle and the matrix, and the indentation depth on the measured hardness. The particle’s work-hardening exponent and the mismatch in particle and matrix yield strength have a significant influence on the measured hardness. A particle-dominated indentation depth was identified, within which the measured nanoindentation hardness agrees very well with the true hardness of the particle material. Numerical results from the simulations of a wide range of material properties determined that the measured hardness is within 5% difference of the particle’s true hardness when the indentation depth is less than 13.5% of the particle’s radius. The results can be used in practice as a guideline to measure the hardness of a particle embedded in a matrix and provides the theoretical basis to develop a particle-embedded method to measure the hardness of individual particles. [ABSTRACT FROM PUBLISHER]

Critical metal sustainability is a worldwide issue whose extraction relies on hydrometallurgy mostly. The significance of metal ion species evolution in critical metal hydrometallurgy-extraction has got more and more attention. Here, the importance of the metal ion species during the whole vanadium recycling process has been evaluated quantitatively for the first time. Metal ion species as the key parameter was investigated through efficiency, material and energy accounting, and emission accounting to illustrate the effect of the metal ion species, which donated as ion species contribution (ISC). Specifically, 7 types of vanadium ion species were assessed in the process of V 2 O 5 production from leachate, including H 2 VO 4 −, HV 2 O 6 −, V 4 O 12 4−, H 2 V 5 O 14 −, V 10 O 28 6−, HVO 4 2− and VO2+. The results demonstrated that different vanadium ion species were closely related to recovery efficiency and purity, and they impact separation section, materials and energy consumption mostly in whole process. Consequently, V 4 O 12 4− occupied the highest ISC which was 1.11 times than V 10 O 28 6−, 1.37 times than VO2+ and 4.85 times than H 2 VO 4 −. Correspondingly, control of V 4 O 12 4− as dominant species appeared to be the most potential in the vanadium extraction process, which showed the feasibility of whole process optimization. With this research, ISC can help to point out dominant ion species in holistic critical metals supply chain, thus promote sustainability of critical metals in a new perspective. • Evaluating in detail the contribution of ion species to the whole V 2 O 5 production. • Covering comprehensive indicators related to ion species evolution. • An effective method for ion species regulation in critical metal resources recovery. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanotube (CNT)–hybridized carbon fibre (CF) composite is a new generation composite, where CNTs grow radially on carbon fibres to form a hybrid reinforcing phase. To evaluate the bridging effect of this new reinforcing phase, a numerical method is proposed to theoretically investigate the pullout of a hybrid fibre. There are two finite element models developed in this method, which are applied to simulate a single CNT pullout from the matrix at microscale and the pullout of the hybrid fibre at macroscale. The bridging effect of the CNTs during the hybrid fibre pullout is simulated by spring elements in the macroscale finite element model, where the properties of spring elements are obtained from the microscale finite element simulation. The numerical results indicate that the apparent interfacial shear strength of the hybrid fibre and the specific pullout energy can be significantly increased due to the additional bonding of the CNT–matrix interface. A parametric study indicates that the bridging effect of the hybrid fibre can be further enhanced by improving the interfacial bonding between CNT and matrix and increasing the size or length of CNTs. This study provides a new numerical method to simulate the multiscale CNT/CF hybrid fibre pullout. [Copyright &y& Elsevier]

• An integrated framework developed to model the key physical aspects of DED: laser-powder interaction; melt pool formation; powder catchment and deposition geometry; dilution and residual stresses. • A novel analytical formulation for gravity-dependent powder flux exiting a co-axial nozzle. • Developed a comprehensive analytical-computational model to predict deposition geometry, contact angle, dilution, and residual stress. • Identified physics-based metrics for favorable depositions and developed data-driven process maps of favorable parameter space. Laser directed energy deposition (DED) is an innovative additive manufacturing technology with tremendous potential for remanufacturing and repairing critical components. For sustainable repair, it is necessary to control the deposition geometry and integrity in terms of residual stresses and dilution. Obtuse contact angles and inadequate dilution can lead to inter-track porosity and cracks at the edge of the deposition-substrate interface. In addition, the fatigue life of the restored part is compromised if tensile residual stresses are induced in the deposited layer. A comprehensive modeling approach presented in this paper integrates analytical formulations for the laser-powder interaction and the powder entrapment in the melt pool, with the finite element models for determining the melt pool characteristics and the residual stresses. This model captures the physics of the key phenomena in DED, namely, power attenuation due to laser-particle interaction, melt-pool formation, powder catchment in the melt pool, and the residual stress evolution due to differential thermal contraction and metallurgical transformations. The model predictions have been experimentally validated for residual stresses, dilutions, catchment efficiencies, powder flux, and deposition geometries for crucible particle metallurgy (CPM 9V) steel powder on H13 tool steel. CPM 9V is a preferred material for repairing H-13 molds. Extensive simulations have been carried out using the comprehensive analytical-computational model to develop data-driven expressions for deposition geometry, normalized dilution, and residual stress as a function of process parameters (laser power, scan speed, and powder feed rate). For identifying the preferred deposition regime, these relations are employed to bifurcate the entire operating space into obtuse and acute contact angle, insufficient and sufficient dilution, tensile and compressive residual stress. Higher P v / m ˙ values yield depositions with the desired acute contact angles and higher specific energies (P / v d) induce favorable compressive longitudinal residual stress in the depositions. [Display omitted] [ABSTRACT FROM AUTHOR]

The main objective of this article is to mechanize the procedure of tracking and describing the various phases of deformation of a biological circular cell during micromanipulation. The devised vision-based methodology provides a real-time strategy to track and describe the cell deformation by extracting a geometric feature called dimple angle. An algorithm based on Snake was established to acquire the boundary of the indenting cell and measure the aforementioned feature. Micromanipulation experiments were conducted for zebrafish embryos. Experimental results were used to characterize the deformation of the manipulating embryo by the devised geometric parameter. The results demonstrated the high capability of the methodology. The proposed method is applicable to the micromanipulation of other circular biological embryos such as injection of the mouse oocyte/embryo. Supplemental materials are available for this article. Go to the publisher's online edition of theInternational Journal of Optomechatronicsto view the supplemental files. [ABSTRACT FROM AUTHOR]

Abstract: The contact conditions at the die radius are of primary importance to the wear response for many sheet metal forming processes. In particular, a detailed understanding of the contact pressure at the wearing interface is essential for the application of representative wear tests, the use of wear resistant materials and coatings, the development of suitable wear models, and for the ultimate goal of predicting tool life. However, there is a lack of information concerning the time-dependant nature of the contact pressure response in sheet metal stamping. This work provides a qualitative description of the evolution and distribution of contact pressure at the die radius for a typical channel forming process. Through an analysis of the deformation conditions, contact phenomena and underlying mechanics, it was identified that three distinct phases exist. Significantly, the initial and intermediate stages resulted in severe and localised contact conditions, with contact pressures significantly greater than the blank material yield strength. The final phase corresponds to a larger contact area, with steady and smaller contact pressures. The proposed contact pressure behaviour was compared to other results available in the literature and also discussed with respect to tool wear. [Copyright &y& Elsevier]

Recycling of spent lithium-ion batteries (LIBs) is of great importance for both critical metal supply and environmental protection. Although the physical chemistry is still focused on pyrometallurgy, hydrometallurgy and electrometallurgy, state-of-the-art recycling technologies are a trend that is turning towards being more material/energy efficient in line with the principles of green chemistry. For instance, selective recycling of specified metals and direct regeneration of battery materials are being trialled to develop short-cut processes that prevent secondary pollution generation and improve the atomic economy during the whole recycling process. In this review, a number of technologies for recycling spent LIBs are overviewed, especially at different recycling stages to stepwise recover battery materials. It is clearly understood that extraction of critical metals and subsequent regeneration of materials are only part of the recycling process, while pretreatment to obtain black mass powder from battery cells and pollution control, in view of the recycling process to minimise environmental impact, are also extremely important. Furthermore, green design of batteries, as well as process design in view of the whole life cycle of LIBs, are topping the list of the research which requires profound and elaborate efforts. It is expected that this review could provide a guideline for implementing green chemistry principles into spent LIB recycling and stimulate further discussions on improving the green degree of the process. [ABSTRACT FROM AUTHOR]

Two pot experiments were conducted to study the effects of intercropping with cadmium (Cd) accumulator plant Eclipta prostrata and hyperaccumulator plant Crassocephalum crepidioides on the growth and Cd accumulation of tomato seedlings. In the preliminary experiment, intercropping with E. prostrata and C. crepidioides promoted the growth and decreased the Cd content in roots and shoots of tomato seedlings. In the further experiment, intercropping with E. prostrata and C. crepidioides had the same effects on the growth and Cd content of tomato seedlings as the preliminary experiment. In the further experiment, when three plant species (E. prostrate, C. crepidioides and tomato) intercropping together, the root and shoot biomasses of tomato seedlings got the maximum, and the Cd content in tomato seedlings got the minimum. Compared with the monoculture of tomato, three plant species intercropping increased the root and shoot biomasses of tomato seedlings by 49.28% and 64.19%, respectively, and decreased the Cd contents in roots and shoots of tomato seedlings by 17.35% and 22.35%, respectively. Intercropping with E. prostrata and C. crepidioides also increased the photosynthetic pigment content and enhanced the antioxidant enzyme activity of tomato seedlings. For accumulator and hyperaccumulator plants, intercropping with tomato inhibited the growth of E. prostrata and C. crepidioides, while increased the Cd content in two plant species. Therefore, intercropping with E. prostrata and C. crepidioides could promote the growth and reduce the Cd uptake of tomato seedlings, and three plant species intercropping together was the best combination. [ABSTRACT FROM AUTHOR]

Although concussions can result in persistent neurological post-concussion symptoms, they are typically invisible on routine magnetic resonance imaging (MRI) scans. Our study aimed to investigate the use of ultra-high-field diffusion tensor imaging (UHF-DTI) in discerning severity-dependent microstructural changes in the mouse brain following a concussion. Twenty-three C57BL/6 mice were randomly allocated into three groups: the low concussive (LC, n = 9) injury group, the high concussive (HC, n = 6) injury group, and the sham control (SC, n = 7) group. Mice were perfused on day 2 post-injury, and the brains were scanned on a 16.4T MRI scanner with UHF-DTI and neurite orientation dispersion imaging (NODDI). Finite element analysis (FEA) was performed to determine the pattern and extent of the physical impact on the brain tissue. MRI findings were correlated with histopathological analysis in a subset of mice. In the LC group, increased fractional anisotropy (FA) and decreased orientation dispersion index (ODI) but limited neurite density index (NDI) changes were found in the gray matter, and minimal changes to white matter (WM) were observed. The HC group presented increased mean diffusivity (MD), decreased NDI, and decreased ODI in the WM and gray matter (GM); decreased FA was also found in a small area of the WM. WM changes were associated with WM degeneration and neuroinflammation. FEA showed varying region-dependent degrees of stress, in line with the different imaging findings. This study provides evidence that UHF-DTI combined with NODDI can detect concussions of variable intensities. This has significant implications for the diagnosis of concussion in humans. [ABSTRACT FROM AUTHOR]

Flange tip lift crossings are widely utilized in modern tramlines to replace traditional crossings to enhance commuters' comfort and prevent crossing nose failures. However, due to altered contact conditions between wheel flanges and ramps of crossings, the use of flange tip lift crossing has led to the critical issue of ramp wear. To resolve this issue, this paper investigated the dynamic contact response of a ramp during in-service loading, as well as the resultant wear of the ramp. With a dynamic finite element model, the local contact pressure and local sliding distance were computed and subsequently applied in a local contact-based wear model to evaluate the nominal wear of the ramp. Our findings indicate that under typical in-service loading conditions, the ramp exhibited up to 120 times more wear than the rail head, owing to increased contact pressure and reduced contact area during the ramp contact. To mitigate this issue, a design change of a gentler ramp inclination from the default 1:100 ramp to a 1:150 ramp could provide approximately 10% wear reduction. In addition, increasing the flange radius by 1 mm could reduce the wear by up to 13%. Conversely, increasing the speed to 45 km/h from the recommended 15 km/h speed may cause up to 5 times more wear. Furthermore, an empty tram showed 56% less wear on the ramp when compared to the condition of the maximum allowable axle load. These results offer an insight into the detrimental wear of ramps used in flange tip lift crossings of tramlines and can assist in the development of new designs and operating guidelines to mitigate ramp wear. • Ramp wear of a tram crossing was investigated using dynamic finite element simulation and a local contact-based wear model. • The wear of the ramp was found to be up to 120 times greater than that on the rail head of tram rails. • Gentler ramp inclination, increased flange radius, reduced vehicle speed and lower axle load can reduce the wear of the ramp. [ABSTRACT FROM AUTHOR]