Mid Sweden University

Global textile production and consumption has increased steadily over the past 15 years, which has caused significant impacts on the climate and the environment. In 2022, the EU launched a strategy for sustainable and circular textiles, stating that extending the life of textile products is the most efficient way to reduce their impact on the climate and the environment. Shell jackets for outdoor use are textile products that are frequently discarded by their first users and re-sold on the second-hand market. This study evaluates the performance of 16 second-hand shell jackets from three second-hand stores in Sweden via material testing of four key functional aspects. Comparing the results with the jackets’ original performance, this study describes the change in functionality over time. The results indicate that air permeability does not change significantly, whereas water repellency, water penetration resistance, and breathability decrease over time, although they do so at different rates. With the aim of promoting circularity and encouraging longer product use, this study also compares the price evolution of jackets with their functionality over time. The results reveal that the resale price of the jackets is lower than could be expected based on the level of remaining functionality in the jackets.

Acquiring knowledge on head traumas is useful since they represent a dangerous outcome of traumatic events. Injury criteria aim to link clinical evidence of injury with experimentally measurable physical quantities, however, recent studies based on numerical methods have pointed out that also other factors could be key contributors to brain injury probability and severity. Providing an experimental measure of more advanced injury criteria is challenging, and only few research groups have started to address the problem. Starting from an existing and validated biofidelic dummy head, advances in the mechanical components and sensors embedded inside the model have been carried out, aiming to improve both bio-fidelity and to address the measure of more advanced criteria. After realizing the prototype, preliminary drop tests were performed impacting the helmeted head over an anvil. Data collected showed increase of injury criteria values with the impact force. Results proved the possibility of using the surrogate for investigating simple and advanced injury criteria, and future works will aim to set test parameters to levels compatible with helmet standards.

<i>Advances in 3D Printing</i> presents an overview of various types of advances in 3D printing. It discusses current research trends, problems, and applications of 3D printing processes and materials. The book also discusses advances in bioprinting, tissue generation, radiotherapy, and safety issues in health care. It showcases applications of 3D printing in digital design, body part surrogates, rheological models, airway stents, 3D-printed cermets, and more. It also discusses advances in biomimetic nanocomposite materials, intellectual property concerns, and safety issues in 3D printing technology.

Electron beam melting (EBM) is one of the constantly developing powder bed fusion (PBF) additive manufacturing technologies (AM) offering advanced control over the manufacturing process. Freedom of component shapes is one of the AM competitive advantages already used at industrial and semi- industrial scale. Development of the additive manufacturing today is targeting both widening of the available materials classes, and introducing new enabling modalities. Present research is related to the new possibilities in tailoring different material properties within additively manufactured components effectively adding “fourth dimension to the 3D-printing”. Specific examples are given in relation to the electron beam melting, but majority of the conclusions are valid for the laser-based PBF techniques as well. Through manipulating beam energy deposition it is possible to tailor quite different material properties selectively within each manufactured component, including effective material density as well as thermal, mechanical, electrical and acoustic properties. It is also possible to acquire by choice both metal-metal composite and completely alloyed material, when blends of precursor powder are used together with the beam energy manipulation.   

In this work, a highly alloyed cold work tool steel, Uddeholm Vanadis 4 Extra, was manufactured via the electron beam melting (EBM) technique. The corresponding material microstructure and carbide precipitation behavior as well as the microstructural changes after heat treatment were characterized, and key mechanical properties were investigated. In the as-built condition, the mi-crostructure consists of a discontinuous network of very fine primary Mo-and V-rich carbides dispersed in an auto-tempered martensite matrix together with ≈15% of retained austenite. Adjusted heat treatment procedures allowed optimizing the microstructure by the elimination of Mo-rich carbides and the precipitation of fine and different sized V-rich carbides, along with a decrease in the retained austenite content below 2%. Hardness response, compressive strength, and abrasive wear properties of the EBM-manufactured material are similar or superior to its as-HIP forged counterparts manufactured using traditional powder metallurgy route. In the material as built by EBM, an impact toughness of 16–17 J was achieved. Hot isostatic pressing (HIP) was applied in order to further increase ductility and to investigate its impact upon the microstructure and properties of the material. After HIPing with optimized protocols, the ductility increased over 20 J. 

The aim of this project was to evaluate effects of backpacks with different design intended for use during cycling on skin-close temperature and relative humidity, oxygen uptake, heart rate and aerodynamic drag. Seven subjects took part in the study cycling on a mountain bike mounted on a “smart trainer” placed on a force plate in a wind tunnel. Three series of experiments were carried out: without backpack, with conventional backpack and with a backpack having innovative rear panel design. As hypothesized, the results showed that an innovatively designed backpack with the ducts deflecting part of the airflow towards some areas of the user’s back provided lower temperature and relative humidity for the microclimate compared to a conventional backpack without airflow channels. Further, reference tests without any backpack resulted in the lowest temperature and humidity. However, no differences were found between the three tests for oxygen uptake, heart rate and aerodynamic drag.

Metal additive manufacturing (AM) is on its way to industrialization. One of the most promising techniques within this field, electron beam melting (EBM), is nowadays used mostly for the fabrication of high‐performance Ti‐based alloy components for the aerospace and medical industry. Among the industrial applications envisioned for the future of EBM, the fabrication of high carbon steels for the tooling industry is of great interest. In this context, the process windows for dense and crack‐free specimens for a highly alloyed (Cr–Mo–V) cold‐work steel powder are presented in this article. High‐solidification rates during EBM processing lead to very fine and homogeneous microstructures. The influence of process parameters on the resulting microstructure and the chemical composition is investigated. In addition, preliminary results show very promising mechanical properties regarding the as‐built and heat‐treated microstructure of the obtained material.

The present paper describes preliminary results of studies carried out using a new measurement setup and a biathlon rifle with two different interchangeable stocks: a commercial, mainly wooden one and one additively manufactured from titanium alloy and a polymer PA 2200, employing lightweight, 3D lattice architecture. A finite element analysis of the predicted mechanical properties of new design elements was carried out prior to the manufacturing. Experiments were carried out using a novel setup for the assessment of athlete and rifle performance in biathlon shooting. Data acquisition was carried out at the rates of few kilosamples per second, using a combination of an airbag-based rifle butt pressure sensor, a trigger loading sensor, strap load cell, and two tri-axis MEMS sensors—an accelerometer and a gyroscope. All tests indicate that a rifle stock additively manufactured from titanium alloy could provide better recoil damping compared to the commercial, mainly wooden one. Together with the high capacity of additive manufacturing technologies in equipment individualization, this may provide additional possibilities for the improvement of sports rifle construction and help athletes achieve better results in competitions.

The paper presents the prospects of additive manufacturing (AM) in metal, using the powder bed fusion (PBF) method Electron Beam Melting (EBM) in fabrication specific steel-based alloys for different applications. The proposed approach includes manufacturing of metals from blended pre-alloyed powders for achieving in situ alloying and the material microstructure tailoring by controlling electron beam energy deposition rate EBM tests were conducted with the blends of 316L stainless steel and Colferoloys 103 and 139, corrosion- and abrasion-resistant iron based materials commonly used for plasma spray coating. Thorough microstructure analysis of the manufactured sample was carried out using electron microscopy and measurements of microhardness and elastic modulus was carried out using nanoindentation. It is concluded that implementation of blended powder pathway in PBF AM allows to widen the scope of available materials through diminishing the dependence on the availability of pre-alloyed powders. Together with beam energy steering this pathway also allows for an effective sample microstructure control at different dimensional scales, resulting in components with unique properties. Therefore, the implementation of ‘blended powder pathway’ in PBF AM provides a possibility of manufacturing components with the composite-like and homogeneous zones allowing for the microstructure control and effectively adding a “4th dimension” to “3D printing".