International Journal of Material Forming最新文献

The paper derives from a simple question that the authors have asked themselves when attending conferences and reading articles on modelling of metal forming processes: is numerical modelling based on FEA still innovative? Are the proposed results able to provide a further effective enhancement to scientific knowledge? And how huge was the effort to obtain such an eventual enhancement? Starting with these questions, the authors applied some basic concepts of Innovation Theory to the last forty years of numerical modelling of forming processes and understood that this technology has reached its natural limit: only small enhancements of modelling performances are obtained despite quite big efforts. Also, research topic trends analysis was performed within ESAFORM community through text mining approaches. Now, to answer the research questions still open, a disruptive discontinuity is necessary, aimed at assessing a new master modelling technology.

This study presents a surrogate model based on the convolutional U-Net architecture to predict the thermal field in a carbon fibre-reinforced thermoplastic tape at the microscale during brief and localized heating. Leveraging microstructure data within a machine learning framework, the proposed model aims to enhance the accuracy of temperature field predictions at a low computational cost. The incorporation of a co-attention mechanism to handle image channels of different nature significantly improves precision, resulting in a strong correlation between the model’s predictions and the ground truth obtained from the numerical solution of the heat equation. This capability enables rapid assessment of diverse microstructures, facilitating optimization and real-time applications in manufacturing settings.

Hydrogen-powered vehicles are set to become a viable alternative for many of the cars currently on the roads. However, even if hydrogen offers a promising eco-friendly solution for the energy transition, several issues related to its storage and delivery need to be resolved in order to predict its wide use in both stationary and automotive applications. Hydrogen has the lowest volumetric energy density of all commonly used fuels (0.01079 MJ/L at atmospheric pressure). However, compression emerges as a direct and effective solution to this issue, with high pressures capable of significantly enhancing hydrogen's energy density, thereby augmenting its practicality. The energy densities achievable under high pressure are indeed impressive, making hydrogen highly practical. In mobile applications, hydrogen is typically stored as a gas in high-pressure composite overwrapped pressure vessels (COPVs). To achieve optimal functionality for high-pressure applications, two fundamental objectives must be met: ensuring exceptional structural integrity and maximizing gas impermeability. The commercialization of these vessels therefore presents a range of engineering challenges, including the development of advanced manufacturing techniques, the enhancement of structural properties, and the selection of appropriate materials, among others. The trend towards high-pressure hydrogen storage tanks is characterized by low cost, lightweight, and favorable safety performance. Consequently, the development of an efficient, sustainable, and safe high-pressure hydrogen storage method is a crucial focus of recent research, aiming to optimize hydrogen's utility in various applications. This review summarizes the latest developments in the most established hydrogen compression technologies.

Most research objects of ring rolling process are axisymmetric ring forgings. With the increasing requirements for energy efficiencies and material savings in the industry, the demand for the type of non-axisymmetric rings is becoming increasingly urgent. In response to this demand, the research proposed a new rolling process by adding a constraint die set in conventional ring rolling machine for the Rings with Island Bosses on Outer Surface. This process includes two stages: 1) the diameter growth stage, ring blank is first rolled between die and mandrel until the outer surface of ring contact around at the inner surface of die; 2) the boss growth stage, the material is gradually extruded into the holes on the inner surface of die. Finite element simulation and physical experiments were carried out to confirm that the proposed rolling process was practicable on conventional rolling machine. By design of experiment of this process, folding and shrinkage defects were studied to determine the range of rolling process parameters. The factors, such as shape, area and fillet radius of boss, ring wall thickness and friction, which affect height of boss in boss growth stage, were investigated. The proposed rolling process is practicable for the Rings with Island Bosses on Outer Surface.

Dissimilar metal laminated composite plates are highly valuable in various applications due to the excellent properties of their constituent materials. However, composite plates produced through roll bonding often exhibit bending, challenging their practical use. Analyzing the underlying causes of bending in roll-bonded composite plates and developing optimized processes to mitigate this issue hold significant theoretical and practical importance. In this study, the commercial finite element simulation software ABAQUS was utilized to simulate the deformation behavior of 6061 aluminum alloy and pure titanium TA1 during symmetric rolling bonding. The effects of plastic deformation differences between dissimilar metals, uneven stress distribution across the thickness, and elastic recovery after rolling on the bending of composite plates were systematically investigated. Finite element models were established for titanium/aluminum composite plates under asymmetric rolling conditions, including identical-diameter differential-speed rolling and differential-diameter identical-speed rolling. The findings reveal that both differential diameters and differential speeds effectively mitigate the bending phenomena caused by deformation incompatibility between dissimilar materials and the uneven stress distribution. Based on these findings, an optimized differential-diameter and differential-speed rolling model was developed. With a low roll diameter of 210 mm and a speed ratio of 1.09, the flattest roll-bonded titanium/aluminum composite plates were achieved compared to other conditions. Additionally, the results of rolling experiments confirmed the high accuracy of the finite element simulations. This study provides valuable guidance for improving the bending behavior of composite plates made from metals with significant performance differences.

This study explores predictive modeling of mechanical properties tensile strength, flexural strength, impact strength, and hardness of natural fiber and filler cashew nutshell waste, sugarcane waste, and polyethylene terephthalate (PET) waste was used as fillers composite materials based on advanced machine learning algorithms. The experiment composition weigth percentages (0%, 5%, 10%, and 15%) were obtained through the literature and intermediate and longer compositions (1%–16%) were approximated using Artificial Neural Network (ANN) and Support Vector Regression (SVR) models. The performance of every algorithm was compared based on statistical measures such as Mean Absolute Error (MAE), Mean Squared Error (MSE), Root Mean Squared Error (RMSE), and the coefficient of determination (R²). The ANN model exhibited better prediction performance with R² values greater than 0.99 in every property, with the lowest error rates, representing high reliability in interpolation as well as extrapolation. SVR also worked satisfactorily, albeit with marginally increased deviations in calculated values at some composition ranges. The work establishes machine learning models specifically ANN as an effective means of simulating composite materials’ mechanical behavior, and an effective method of material design optimization that can be done with less experimental labor.

The benchmark 2024 project on Incremental Sheet Forming (ISF), involving 15 research institutes in 13 experimental contributions, provided a unique opportunity to compare experimental outputs from various setups and forming strategies in ISF. This collaboration led to the development of uniform data exchange formats, measurement guidelines, and standardized nomenclature, fostering efficient future collaborations. The project addressed challenges in geometric accuracy when forming a relatively large part (400 × 400 mm) using Single Point Incremental Forming (SPIF) and focused on multiple common pitfalls in ISF, in particular the tent effect and pillow effect. Additionally, some experiments have been conducted using Two Point and Double Sided Incremental Forming (TPIF and DSIF). By combining the knowledge and experience of all participating institutes, this project aimed to provide insights into effective parameter choice and toolpath strategies, and shows the importance of multi-stage processes to increase the geometric accuracy. Despite the theoretical simplicity of SPIF setups, such multi-stage toolpath strategies directed toward improved geometric accuracy also add some new challenges. The study highlighted the need for multi-stage strategies that focus on local effects, as well as geometric compensation techniques to enhance ISF's industrial applicability. Alternative process variants like TPIF and DSIF, showed promising results, but they also had limitations and presented challenges, emphasizing the importance of predictive simulation tools to further increase geometric accuracy. The scalability of ISF experiments remains a significant challenge, necessitating further research into scale laws for process optimization.

Despite its critical importance in governing the weld strength and residual stress of dissimilar aluminum/magnesium welds by friction stir welding, the in-process temperature characteristics remain a subject of ongoing debate. This paper aims to resolve this debate through computational fluid dynamics simulation with the best accuracy to date, enabled by a state-of-the-art shear boundary model that allows fully coupled analysis of interfacial friction, material flow, heat generation and heat transfer. It is revealed that the temperature on the magnesium side is higher than that on the aluminum side, despite nearly identical total heat generation rates on both sides. This asymmetry is attributed to magnesium’s lower thermal conductivity, which impedes heat conduction. It is interesting to note that the circumferential temperature variation is reduced in high-velocity zones near the tool pin due to enhanced convection. The accuracy of the simulation is rigorously validated via comprehensive comparison between the measured welding temperature and the observed joint macrograph, confirming its capability to resolve the long-standing debate in the in-process temperature characteristics. These insights shed new lights on the thermal processes regarding the dissimilar aluminum/magnesium FSW, offering a foundation for optimizing welding process and weld performance.

The supply chains of extruded aluminum are materially inefficient, with up to two-fifths of the billet being scrapped before the profile is incorporated into a final product. A significant source of process scrap arises from removing the tongue-shaped transverse weld—also known as the front-end defect or charge weld—that is formed between the consecutive billets being extruded, primarily because of concerns over weld integrity. Optimizing process settings and die geometry can reduce the transverse weld length—and thus the amount of scrapped material—but only by approximately 15%. We investigate a novel methodology for significant scrap reduction, where an initially profiled interface—rather than a flat one—between consecutively extruded billets compensates for the differential velocities of material across the billet cross-section as it moves through the die ports, resulting in shorter welds. This profiled interface is created using profiled billets that fit into a dummy block shaped with the inverse of the billet profile. We present a design process to define the shape of the profiled dummy block and billet. For a given part, we first determine the ideal shape by obtaining the velocity field from finite element simulations of the conventional extrusion process, assuming perfectly rigid tooling and no constraints on the creation of profiled tooling or billets. Next, we rationalize this shape by applying stress and deflection limits to the dummy block, ensuring it avoids plastic deformation and interference with the container wall. Additionally, we consider ductile damage limits for the billet to prevent cracking during a pre-extrusion hot forging stage, which is one method of generating profiled billets. The design process is applied to four profiles of increasing complexity: solid round and rectangular bars, a square-tube hollow, and a complex multi-hollow profile. Extrusion and forging trials using custom-built tooling are conducted to validate the design process. The experimental case studies demonstrate that profiled dummy blocks and billets can achieve weld length reductions of over 50% and that the same tooling can offer scrap savings across a range of similar extruded shapes. In the tests, a profiled dummy block with an air escape vent showed zero-to-negligible plastic deformation and neither air entrapment nor clogging of the vent during extrusion, while a conventional billet was hot-forged to produce profiled ends without cracking or deforming the forging tools. Overall, this study highlights that profiled billet extrusion is a promising technology for significantly reducing scrap from transverse weld removal in aluminum extrusions.

Tin bronze valve bodies are widely used in fluid control systems requiring high corrosion resistance. However, conventional casting introduces defects such as porosity, segregation, and “sweating tin,” while forging is limited by the alloy’s thermal brittleness and difficulty in forming complex geometries. These issues hinder the integration of structural complexity with high mechanical performance. To address this, a novel integrated casting-forging process is proposed, consisting of three stages: casting, thermal holding at forging temperature, and hot forging. Using C83600 tin bronze, hot compression tests were conducted to construct a processing map and determine the optimal hot working parameters. A coupled simulation framework based on THERCAST and FORGE was developed to model solidification, homogenization, and forging, validating the feasibility of both bidirectional and triaxial extrusion schemes. Experimental trials confirmed that forging the billet while hot enabled seamless process transition, enhanced stability, and reduced cycle time. The resulting valve bodies exhibited significantly improved density of 9.25 g/cm³ and mechanical properties, hardness of 169 HB. This integrated approach demonstrates clear technical feasibility and practical potential for high-performance tin bronze component manufacturing.