High efficient material and process combination for future aircraft applications based on advanced sheet molding compound technologies

The increasing need for efficient passenger aircraft led to the development of innovative lightweight designs and an increasing demand on new lightweight materials such as carbon fiber reinforced plastics (CFRP) in the recent decades. Due to the high weight specific mechanical properties and the relatively high cost of raw materials, semi-finished and manufacturing the use of CFRP is limited on high performance applications, especially for components of the primary structures of aircraft. Subsequently, fiber reinforced plastics (FRP) are also used in cabin and interior. Due to lower mechanical loads, but high requirements on fire protection, optics, surface and acoustics sandwich structures are used in most cases. Generally, these sandwich structures are made of honey comb cores and top layers based on glass fiber fabrics impregnated by phenolic resin. However, higher complexity of the parts, directly integrated functions and the required surface properties for applying the decorative films or paintings can only be realized by a lot of manufacturing, finishing and assembly steps. In order to meet the increasing demands for lightweight structures for cabin and cargo applications the aerospace industry is working on improvements and developments of new materials, manufacturing processes and construction methods for secondary structures. One auspicious technology is the combination of Sheet Molding Compounds (SMC) with long fiber reinforcements and directed, pre-impregnated continuous fiber reinforcements, which are processed in a single-stage pressing and curing process to produce a new kind of hybrid composite components for aircraft. This hybrid composite technology is characterized by the realization of geometrically complex, highly functional and lightweight components with low process cycle times in the range of 30 to 180 seconds. Depending on the specific requirements and the application thermoset matrix systems based on unsaturated polyester, vinyl ester or epoxy resins can be used. The ability of full automation and the relatively high material usage in the range of 90 percent and higher make this technology economically efficient. In addition, the process obtains the possibility to integrate various functions directly. Coloring and the direct integration of metallic components such as inserts or nuts are only some examples for that. Time and costs for rework assembly and further process steps can be reduced due to the extended possibilities of functional integration and the higher complexity of the components. In addition, an optimized utilization of material and the possibility of using recycled carbon fibers from a pyrolysis process or dry chopped fibers from production waste obtain an increase of resource and energy efficiency. The carbon fibers may be reused as long-fiber reinforcements for veils. Due to the described potentials there are a lot of auspicious applications of this hybrid composite material for future aircraft cabins. Load carrying cabin monuments, highly functional storage systems for hand luggage, complex fittings, holders or brackets are only some exemplary applications. By the integration of continuous fiber reinforcements following the load paths of the appropriate component high lightweight potentials and also structural applications can be realized. However, the high requirements on fire, smoke and toxicity (FST) and the required lightweight specifications of cabin and cargo structures create huge challenges for the material and the process development. This publication deals with the development of the combination of SMC and pre-impregnated, tailored carbon fiber reinforcements for cabin and cargo applications in aerospace industry. The main focusses are different investigations on the material properties and analyses of the manufacturing procedures of advanced SMC formulations based on unsaturated polyester resin with a high proportion of the inorganic flame retardant additives as well as aluminum trihydrate (ATH). Generally, a high degree of fire resistance additives has negative effects on the fiber-resin adhesion, the impregnation of the fibers and the flow behavior during the compression molding. Nevertheless, the findings on this hybrid composite technology obtain promising possibilities for functional integrations, lightweight constructions and the cost-efficient production of secondary structure aircraft components

Combination of Carbon Fibre Sheet Moulding Compound and Prepreg Compression Moulding in Aerospace Industry

AbstractThe demand for fuel efficient aircraft led to the development of innovative lightweight constructions and the use of lightweight materials, such as carbon fibre reinforced plastics. In the same manner competences in new production technologies have been built up in the aerospace industry. However, current processes for producing lightweight composites with an excellent mechanical performance cause high costs and long process cycles in comparison with approved metal processes. Furthermore the used raw materials, such as carbon fibres and resin, are very expensive. In contrast to these technologies Sheet Moulding Compound is characterised by a very high productivity, excellent part reproducibility, cost efficiency and the possibility to realise parts with complex geometries and integrated functions, e.g. inserts or colouring. The biggest disadvantage of Sheet Moulding Compound parts is a low level of stiffness and strength because of a low fibre-volume fraction, a short fibre length and isotropic fibre distribution. In this context the combination of Sheet Moulding Compound and Prepreg compression moulding in an one-shot compression moulding and curing process merges the advantages of both materials to create load-bearing and autoclave-quality parts without an autoclave. In the following article, this new technology and its potential will be presented. This paper will also deal with the resulting material characteristics

Digital Twin Fidelity Requirements Model for Manufacturing

The Digital Twin (DT), including its sub-categories Digital Model (DM) and Digital Shadow (DS), is a promising concept in the context of Smart Manufacturing and Industry 4.0. With ongoing maturation of its fundamental technologies like Simulation, Internet of Things (IoT), Cyber-Physical Systems (CPS), Artificial Intelligence (AI) and Big Data, DT has experienced a substantial increase in scholarly publications and industrial applications. According to academia, DT is considered as an ultra-realistic, high-fidelity virtual model of a physical entity, mirroring all of its properties most accurately. Furthermore, the DT is capable of altering this physical entity based on virtual modifications. Fidelity thereby refers to the number of parameters, their accuracy and level of abstraction. In practice, it is questionable whether the highest fidelity is required to achieve desired benefits. A literary analysis of 77 recent DT application articles reveals that there is currently no structured method supporting scholars and practitioners by elaborating appropriate fidelity levels. Hence, this article proposes the Digital Twin Fidelity Requirements Model (DT-FRM) as a possible solution. It has been developed by using concepts from Design Science Research methodology. Based on an initial problem definition, DT-FRM guides through problem breakdown, identifying problem centric dependent target variables (1), deriving (2) and prioritizing underlying independent variables (3), and defining the required fidelity level for each variable (4). This way, DT-FRM enables its users to efficiently solve their initial problem while minimizing DT implementation and recurring costs. It is shown that assessing the appropriate level of DT fidelity is crucial to realize benefits and reduce implementation complexity in manufacturing

Integrating system and operator perspectives for the evaluation of power-to-gas plants in the future German energy system

In which way, and in which sectors, will renewable energy be integrated in the German Energy System by 2030, 2040, and 2050? How can the resulting energy system be characterised following a −95% greenhouse gas emission reduction scenario? Which role will hydrogen play? To address these research questions, techno-economic energy system modelling was performed. Evaluation of the resulting operation of energy technologies was carried out from a system and a business point of view. Special consideration of gas technologies, such as hydrogen production, transport, and storage, was taken as a large-scale and long-term energy storage option and key enabler for the decarbonisation of the non-electric sectors. The broad set of results gives insight into the entangled interactions of the future energy technology portfolio and its operation within a coupled energy system. Amongst other energy demands, CO2 emissions, hydrogen production, and future power plant capacities are presented. One main conclusion is that integrating the first elements of a large-scale hydrogen infrastructure into the German energy system, already, by 2030 is necessary for ensuring the supply of upscaling demands across all sectors. Within the regulatory regime of 2020, it seems that this decision may come too late, which jeopardises the achievement of transition targets within the horizon 2050

Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members

Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic. Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine. Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis. Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years

Usability of a mHealth solution using speech recognition for point-of-care diagnostic management

The administrative burden for physicians in the hospital can affect the quality of patient care. The Service Center Medical Informatics (SMI) of the University Hospital Würzburg developed and implemented the smartphone-based mobile application (MA) ukw.mobile1 that uses speech recognition for the point-of-care ordering of radiological examinations. The aim of this study was to examine the usability of the MA workflow for the point-of-care ordering of radiological examinations. All physicians at the Department of Trauma and Plastic Surgery at the University Hospital Würzburg, Germany, were asked to participate in a survey including the short version of the User Experience Questionnaire (UEQ-S) and the Unified Theory of Acceptance and Use of Technology (UTAUT). For the analysis of the different domains of user experience (overall attractiveness, pragmatic quality and hedonic quality), we used a two-sided dependent sample t-test. For the determinants of the acceptance model, we employed regression analysis. Twenty-one of 30 physicians (mean age 34 ± 8 years, 62% male) completed the questionnaire. Compared to the conventional desktop application (DA) workflow, the new MA workflow showed superior overall attractiveness (mean difference 2.15 ± 1.33), pragmatic quality (mean difference 1.90 ± 1.16), and hedonic quality (mean difference 2.41 ± 1.62; all p < .001). The user acceptance measured by the UTAUT (mean 4.49 ± 0.41; min. 1, max. 5) was also high. Performance expectancy (beta = 0.57, p = .02) and effort expectancy (beta = 0.36, p = .04) were identified as predictors of acceptance, the full predictive model explained 65.4% of its variance. Point-of-care mHealth solutions using innovative technology such as speech-recognition seem to address the users’ needs and to offer higher usability in comparison to conventional technology. Implementation of user-centered mHealth innovations might therefore help to facilitate physicians’ daily work

Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members

Background The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey , a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic. Methods A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine. Results 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis. Conclusions The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years