Materialwissenschaft und Werkstofftechnik最新文献

One of the main challenges in the automotive industry is the development of lightweight components reducing energy consumption and emissions during production and use. For this purpose, material selection and the production process must be optimized. Lightweight, high-performance materials such as long fiber thermoplastics (LFT) and lightweight technologies such as foam injection molding (FIM) are therefore ideal for achieving high weight reductions through adapted component designs. With the foam injection molding technology ProFoam, it is possible to achieve longer fibers in the component with long-fiber thermoplastics and thus the weight-specific properties can be improved. To analyze the potential of the foam injection molding process for the design freedom of lightweight components, plates with ribs are manufactured using injection molding and foam injection molding with a 10 % weight reduction. The process parameters injection speed, melt and mold temperature and the rib geometries are analyzed in this contribution. During foam injection molding process, it is found that cell formation and fiber length are significantly affected by melt temperature and injection speed, which influence further the mechanical properties

Eine der größten Herausforderungen in der Automobilindustrie ist der ressourceneffiziente Leichtbau, um den Energieverbrauch und die Emissionen während der Produktion und Nutzung zu reduzieren. Zu diesem Zweck müssen die Materialauswahl und der Produktionsprozess optimiert werden. Hochleistungswerkstoffe wie langfaserverstärkte Thermoplaste (LFT) und Leichtbautechnologien wie das Thermoplast-Schaumspritzgießen (TSG) ermöglichen durch angepasste Bauteilkonstruktionen hohe Gewichtsreduktionen. Mit dem Thermoplast-Schaumspritzgieß-Verfahren ProFoam werden bei der Verarbeitung von langfaserverstärkten Thermoplasten längere Fasern im Bauteil realisiert und damit die gewichtsspezifischen Eigenschaften verbessert. Um das Potenzial des Thermoplast-Schaumspritzgießens für die Gestaltungsfreiheit von Leichtbauteilen zu analysieren, werden Platten mit Rippen im Kompaktspritzgießen und im Thermoplast-Schaumspritzgießen mit einer Gewichtsreduktion von 10 % hergestellt. Die Prozessparameter Einspritzgeschwindigkeit, Schmelz- und Werkzeugtemperatur sowie die Rippengeometrien werden in dieser Arbeit analysiert. Beim Thermoplast-Schaumspritzgießen beeinflussen die Morphologie und die Faserlänge die mechanischen Eigenschaften. Dabei sind die wesentlichen Einflussfaktoren auf die Morphologie und die Faserlänge die Schmelzetemperatur und die Einspritzgeschwindigkeit.

This review provides an insightful exploration into the dynamic landscape of contemporary battery technologies, delving beyond conventional limits to uncover the latest advancements. The evolutionary trajectory of battery technology is scrutinized, offering a comprehensive overview of ongoing research endeavors. Focusing on critical components, the cathode, anode, and electrolyte are dissected to unveil innovative materials and designs propelling the field forward. Safety considerations, a paramount aspect of battery development, receive meticulous attention, highlighting novel strategies and technologies ensuring secure operations. Embracing the era of artificial intelligence, the integration of machine learning in battery research is discussed, showcasing its transformative impact on optimization, prognostics, and life prediction. This review encapsulates a panoramic view of the present battery landscape while providing a roadmap for the future. By synthesizing advancements across various fronts, it aims to guide researchers, engineers, and enthusiasts towards a deeper understanding of cutting-edge battery technologies, ultimately empowering the trajectory of energy storage systems into an era of unprecedented possibilities.

Existing studies that assess ice strain behavior do not consider the presence of a permanent inelastic strain that is independent of time, such as is observed in other materials. To investigate permanent inelastic strain and to determine the other strain components for ice, we performed creep tests on polycrystalline isotropic ice under a constant uniaxial compression load at several loading and unloading times and temperatures of -5 °C, -10 °C, and -15 °C. Plastic strain decreases as temperature decreases. However, relative to other strain components, the contribution of plastic strain to total strain is important at all temperatures, particularly when the ice is close to its melting point. The contribution of primary creep strain is greater at the beginning of the loading process, and secondary creep eventually dominates as loading continues. The contribution of primary creep to permanent strain increases markedly as temperature decreases, whereas the contribution of secondary creep increases with temperature.

The study characterizes the effects of intensive plastic deformation, realized by the rotary swaging method, on the deformation behavior of WNiCo tungsten heavy alloy samples. To assess the differences in the deformation behaviors of the samples, evaluated via uniaxial compression tests (UCT), and characterize the microstructures, i. e. occurrence and development of hardening/softening processes, two different temperatures of swaging (900 °C and 1200 °C), and two different uniaxial compression testing temperatures (1100 °C and 1200 °C), were used. A relatively high strain rate of 10 s⁻¹ was chosen for the testing because of the typical use of the tungsten heavy alloy for kinetic penetrators. The achieved results indicate that the development of softening processes, especially dynamic recrystallization, can occur within the swaged material, depending on the processing/testing conditions. Swaging at the lower temperature of 900 °C introduced significant work hardening and accumulation of strain, which promoted the development of dynamic recrystallization during the subsequent hot temperature testing. Swaging at 1200 °C, on the other hand, facilitated dynamic recrystallization and relaxation (especially within the nickel-cobalt matrix) already during processing, which consequently increased the activation energy necessary for the development of recrystallization during the hot testing.

Wood-based panels such as fiberboard, have become indispensable materials in everyday life - from furniture to outdoor paneling. Despite the widespread use of Industry 4.0 methods across all industry sectors, their application in the wood-based panel sector has been very limited so far. This study highlights the untapped potential of Industry 4.0 in the wood-based panel sector by using digital methods to improve finishing of wood-based panels with resin-impregnated papers in a short-cycle hot press by thermal modelling. For an accurate temperature estimation, precise heat transfer coefficients are of great importance. Currently, no data for these heat transfer coefficients are available in literature. We used experimental data in combination with a digital thermal model to determine the heat transfer coefficients of the system by using an optimization algorithm. In this work, we describe the experimental setup used, the extensive measurement campaigns conducted and how the digital model was validated and adjusted to allow the optimization algorithm to produce accurate estimations of the system′s heat transfer coefficients. In conclusion, our study underscores the potential of Industry 4.0 methodologies in the underrepresented field of wood-based panel manufacturing by utilizing a combination of experimental and modern digital methods.

With the ongoing digitalization in the industrial sector, also called Industry 4.0, automation techniques offer huge potential for the rubber industry. Advanced automation methods allow for precise control of the extrusion process and increase the consistency in product quality. Since product quality is affected by process parameters in a complex way, predicting the flow conditions, the thermal conditions and the mixing in an extruder is a prerequisite for more sophisticated Industry 4.0 applications. These Industry 4.0 applications require short computing times and thus sufficiently fast models for online implementation in production systems. A useful measure for the flow inside the extruder is the residence time distribution. It enables an analysis of the residence time of the material particle in the process and subsequently a statement about the mixing characteristics. For the investigation of the residence time distribution and the effect of process parameters on residence time properties, a single-screw rubber extruder equipped with a gear pump was used. In this contribution, we present a method to identify the residence time distribution for a certain compound using experiments. We describe an experimental procedure with a special tracer material and a modified image processing method to identify the residence time distribution. The experimental data and analyses, in particular, the input and output signals of the experiments, are used to determine the residence time distribution (transfer function) of the system. Based on previous findings from literature and experimental studies of the process, the influences of selected parameters on the transfer function were investigated and used to parameterize a general transfer function for the chosen compound. Consequently, the derived transfer function is used to predict the residence time distribution of the process and the results are validated with experimental data. We discuss the potential of the method for an online implementation in a production system and outline how this method can be used within predictions for advanced process control.

Polyurethane-silica aerogel (PUSA) composite has shown promising performance in thermal insulation application, owing to its microstructure that offers thermal resistance within its cellular matrix. The inclusion of silica aerogel into polyurethane enhances both the mechanical and thermal properties of the composite. Previous research reported 1 wt.–% silica aerogel loading as optimal in material compressive strength and higher concentrations was found to negatively impact the cell structure and ultimately hinder thermal performance. In the quest for enhanced properties cellulose fibre (CF) was introduced into polyurethane-silica aerogel. Composites with variable loading of cellulose fibre (0.5 wt.–%, 0.75 wt.–% and 1.0 wt.–%) as PUCF1S, PUCF2S and PUCF3S were fabricated. It was found that composite PUCF2S has the highest compressive strength of 0.92 MPa, demonstrating 64 % increase compared to pristine composite (polyurethane-silica aerogel). The matrix microstructure as revealed by field emission scanning electron microscopy was discovered to have uniform cell size facilitated by uniform particle dispersion within the matrix. The cellulose fibre participated in the cell nucleation leaving behind an enhanced cell with reduced cell size that supports compressive loads and thermal insulation performance.