HLFC leading edge in automated autoclave infusion

Maximising ECO-Efficiency of future aircrafts by minimizing friction drag is the main motivation of the “HLFC-HTP” project within Clean Sky 2. To achieve this, a HLFC (Hybrid Laminar Flow Control) approach at the HTP (Horizontal Tail Plane) was selected. This approach combines a suction system in the leading edge with a rather conventional, just surface optimized HTP box structure. Despite many other laminarity related projects in the past the major objective of the “HLFC-HTP” project is to provide a competitive suction system that is integrated in the leading edge structure and that is suited for series production without trading in aerodynamic drag reduction potential. The required suction pressure distribution at the leading edge is established by 22 chambers with adjusted vacuum pressure and distributed electrical compressors to provide the vacuum pressure. To minimize piping effort and piping losses the compressors are located directly in the leading edge with their respective outlets leading the exhaust through the spar into the HTP box. In order to address the space allocation aspect, the concept verification has been done on the basis of small-scale demonstrators with a representative cross section of the smaller, outer HTP leading edge. The major elements of the leading edge structure are a composite load bearing skin structure with a number of integrated spacers to build up the required chambers and a microperforated Titanium outer skin. The skin allows to remove the critical boundary layer and provides the required erosion resistance. In order to minimise tooling costs and lead time an open mould resin infusion process was selected to manufacture the rather complex composite prototype structures. Since the final series production was planned as an RTM (Resin Transfer Moulding) process it has been decided to use an autoclave and the option of a pressure assisted infusion. 5 different prototype structures with different preform configurations have been manufactured and assessed in order to identify the most mature and production friendly setup. Furthermore, a newly developed, fully automated “Digital Infusion Center” has been used for the final production sequence. The “Digital Infusion Center” accepts simple resin storage tin cans and uses microwaves to quickly adjust the target resin temperature. To record the infusion process the “Digital Infusion Center” precisely monitors the resin flow and other relevant process parameters. The Titanium skin is finally bonded to the inner composite structure using a sequential process with a specialized, pressure controlled bonding fixture. Currently the final prototype is prepared for the impact test that will show the structural performance of the novel design. Based on an estimated aircraft production rate of 15 A/C per month (long range, wide body) an assessment of the production sequence showed that series manufacturing cost could be reduced by more than 75% in comparison with the prototype production. The major cost reduction potential has been identified for the preforming sequence but also a lean and energy efficient, isothermal RTM infusion and curing approach would contribute to the cost reduction

Perspektive Composites in der Luft- und Raumfahrt

Leichtbau ist ein entscheidender Faktor für die Absicherung der Mobilität in einer nachhaltig gestalteten Zukunft. Das global vernetzte Deutsche Zentrum für Luft- und Raumfahrt trägt mit seinen Forschungseinrichtungen dazu bei, insbesondere den Leichtbau mit faserverstärkten Kunststoffen in einer großen Bandbreite verfügbar zu machen. Durch die Forschung entlang der gesamten Prozesskette vom Material über das Design bis hin zur Produktion werden dabei individuelle Lösungsansätze entwickelt und zusammen mit Forschungspartnern unter anwendungsnahen Randbedingungen erprobt und validiert. Neben den Schwerpunktthemen Luft- und Raumfahrt stehen im Fokus der Forschung auch andere Anwendungsfelder wie Energie, Verkehr, Sicherheit und Digitalisierung. Die Pflege und Weiterentwicklung von Großanlagen die auch eine Untersuchung und Bewertung von Bauteilen im Originalmaßstab von bis zu 20m Länge erlauben, sind dabei ein wichtiges Alleinstellungsmerkmal

Virtuelles Produkt und digitale Zwillinge für die Entwicklung innovativer Flugzeugkomponenten

Die Digitalisierung ermöglicht eine Steigerung der Effizienz bei der Herstellung und Zulassung von Faserverbundstrukturen. Anhand der Fertigung einer 2,5m langen Vielholmer-Landeklappe in einem sensorunterstützten RTM (Resin Transfer Moulding) Prozess wurden die Machbarkeit eines solchen Ansatzes demonstriert

"Eurasien" - Phantom oder reales Entwicklungsmodell für Russland?

In dem vorliegenden Papier werden zwei Perspektiven auf den heutigen Eurasismus in Russland, die empirische und die politisch-ideologische, miteinander in Beziehung gesetzt. Zunächst wird ein Blick auf die postsowjetischen Kontroversen um die Eurasier und den Eurasismus in Russland geworfen. Stärker als dies andernorts zumeist geschieht, wird dabei auf die interne Heterogenität des Eurasismus-Konzepts abgezielt, das nicht von vornherein auf rückwärtsgewandte, nationalistische Politikmuster festgelegt ist, sondern im Prinzip auch pragmatischeren Lesarten offen steht - die sich aber in den jüngsten Debatten nicht haben durchsetzen können. Sodann wird danach gefragt, ob Russland im Laufe seiner jüngsten Entwicklung tatsächlich "asiatischer" geworden ist. Auch wenn sich gegenwärtig noch kein eindeutiges Bild ergibt, zeigen sich doch gewisse Tendenzen, die für eine solche "Osterweiterung" Russlands sprechen. Dabei ist aber entscheidend, dass diese nicht mehr ausschließlich in den traditionellen Bahnen einer machtstaatlichen Sicherung von Räumen und Ressourcen verläuft, sondern als ein komplexes Zusammenspiel vielfältiger gesellschaftlicher, ökonomischer, politischer und kultureller Entwicklungen zu verstehen ist. Es erscheint fraglich - so die These, die im Weiteren begründet wird -, dass die Eurasiendebatte geeignet ist, die hieraus erwachsenen Herausforderungen für die politische Kultur des Landes zu reflektieren und in realitätstaugliche Deutungsmuster umzusetzen. (ICD2

ASSESSMENT-BASED ECO-EFFICIENCY ESTIMATION OF COMPOSITE AND HYBRID STRUCTURES IN COMMERCIAL AIRCRAFT

In the early development stage, decision-makers select the product specifications. These demand-oriented specifications are achieved by configuring the associated processes. Such decision-making may be involved with various life-cycle stages and multiple development disciplines. Therefore, decision-support systems (DSSs) are essential to facilitate the decision-making process on strategic, tactical, and operational managerial levels. To consult the decision-makers, success factors are to be defined and evaluated. Success factors such as the sustainability aspects such as economic and ecological impacts may be evaluated on different levels starting from the global key-result indicators (KRIs). To serve different managerial levels by such DSSs, combining what are known as top-down and bottom-up evaluation approaches is crucial. In practice, a DSS provides the assistance regarding a specific selection of KRIs. In this work, economic as well as ecological KRIs are evaluated by the applied DSSs. Therefore, two DSSs are discussed in this paper. The first DSS is the Eco-Efficiency Assessment Model (EEAM), which has been developed by the German Aerospace Center (DLR) as a bottom-up assessment tool for the production of composite and hybrid structures. In this work, EEAM is implemented to assess the economic and ecological KRIs of the “as-is” prototype manufacturing process at DLR laboratories. Based on EEAM, an Eco-Efficiency Estimation Model (E³M) is developed as the second DSS in this work. E³M evaluates the economic and ecological impacts of the “as-if” industrial scenarios by deriving a top-down estimation based on the bottom-up assessment. The advantage of this approach is the possibility of validating the data-based bottom-up assessment and consequently the assessment-based estimation. As a case study, a novel design of a suction rib for a hybrid laminar flow control (HLFC) wing is selected in this work. While HLFC offers advanced performance during operation phase in the life-cycle of commercial aircraft, decision-makers need to investigate the performance of the selected KRIs such as direct cost and carbon footprint in the other life-cycle phases. Despite the fact that all other phases are decisive, this work focusses on the manufacturing process. After performing a data-based eco-efficiency assessment of the “as-is” suction rib manufacturing, an estimation of “as-is” industrial manufacturing is derived. The results of both “as-is” and “as-if” scenarios show a reduction in the direct manufacturing cost of the suction rib from 4.9 k€/kg of the final structure to 0.395 k€/kg, in the carbon footprint from 313.9 kg CO2/kg to 93.7 kg CO2/kg, as well as the by the product material waste from around 65% to 38% respectively

Milieu-specific differences in symptom severity and treatment outcome in psychosomatic rehabilitation in Germany

IntroductionPrevious studies that focused on socioeconomic differences did not comprehensively explain existing inequalities in psychosomatic rehabilitation in Germany. We applied a social milieu approach, which additionally includes sociocultural factors such as lifestyles, attitudes and values, to investigate differences among patients in symptom severity, psychosocial impairment and improvement over the course of the intervention.MethodsAs a model for social milieus, the empirical Sinus milieus were used. 2,000 patients of two psychosomatic rehabilitation clinics in Germany were included and their milieu was assessed with the Sinus milieu indicator for Germany 10/2018 questionnaire. BDI-II (N = 1,832) and HEALTH-49 (N = 1,829) questionnaires were used to measure depressiveness and psychosocial impairment at admission (T0) and discharge after 5 weeks of treatment (T1). Milieu differences in severity and improvement were analyzed by mixed-model ANOVAs.ResultsMilieu distribution was not representative of the overall population of Germany. We found significant differences between patients from different milieus in both BDI-II and HEALTH-49 (p < 0.001). Patients from the Precarious Milieu had the highest burden of depressive symptoms in BDI-II and the highest impairment on all HEALTH-49 scales at T0 and T1. Over the course of rehabilitation, patients from all milieus improved significantly in all domains (p < 0.001). Significant interaction effects showed milieu-dependent differences in improvement for depressiveness on the BDI-II [F(9, 1822) = 2.50, p = 0.008] and for three HEALTH-49 scales, namely Psychological well-being [F(9, 1819) = 3.30, padj = 0.005], Interactional difficulties [F(9, 1819) = 2.74, padj = 0.036] and Activity and Participation [F(9, 1819) = 4.94, padj < 0.001], while post-hoc tests only revealed two significant group differences for the last scale. In all domains, patients from the Precarious Milieu retained higher symptoms and impairment at T1 than patients from better-off milieus had at T0.DiscussionSocial milieu was associated with symptom severity, treatment access and outcome of psychosomatic rehabilitation patients. Milieu-specific sociocultural habits, psychosocial needs and therapeutic demands may help describe differences and should be considered in therapy planning and implementation, to improve equal access, quality and effectiveness of rehabilitation. Therefore, further research on milieu-specific differences and needs is necessary

Leichtbauproduktion von morgen - Digitalisierung als Wegbereiter für nachhaltige Fertigung

Welchen Beitrag kann Digitalisierung für eine nachhaltige Fertigung leisten? Digitalisierungsansätze und Beispiel aus dem DLR-Institut FA