Numerical investigations regarding a novel process chain for the production of a hybrid bearing bushing

This contribution deals with the numerical investigations to develop a novel process chain for hybrid solid components using Tailored Forming. For manufacturing a hybrid bearing bushing, co-extrusion is the first step to produce hybrid semi-finished workpieces followed by a die forging process, machining processes and hardening. Combining aluminium with steel, compounds with wear-resistant functional surfaces and reduced weight are realised. Numerical simulations are a decisive part of the process chain design, for example to determine suitable process parameters for the co-extrusion process and to predict the thickness of intermetallic phases in the joining zone using a macroscopic phenomenological model. A numerical design including a tool analysis of the die forging process was carried out taking the experimentally determined material properties and the temperature profile after inductive heating into account. Additionally, the damage and fatigue behaviour of the polycrystalline material of the joining zone are modelled at the microstructure level. Moreover, a new discretization scheme, namely the virtual element method, which is more efficient at grain level, is developed regarding a crystal plasticity framework. Numerical simulations are used to develop inductive heating strategies for the forming process and for the design of the inductive hardening of the functional surface at the end of the process chain. In order to investigate the performance of this hybrid machine element under application-oriented conditions, a contact simulation is linked with a statistical damage model to calculate the bearing fatigue. In this study, a general overview of the individual process steps is given and results of the respective models are presented. © 2020, The Author(s)

Investigations on tailored forming of aisi 52100 as rolling bearing raceway

Hybrid cylindrical roller thrust bearing washers of type 81212 were manufactured by tailored forming. An AISI 1022M base material, featuring a sufficient strength for structural loads, was cladded with the bearing steel AISI 52100 by plasma transferred arc welding (PTA). Though AISI 52100 is generally regarded as non-weldable, it could be applied as a cladding material by adjusting PTA parameters. The cladded parts were investigated after each individual process step and subsequently tested under rolling contact load. Welding defects that could not be completely eliminated by the subsequent hot forming were characterized by means of scanning acoustic microscopy and micrographs. Below the surface, pores with a typical size of ten µm were found to a depth of about 0.45 mm. In the material transition zone and between individual weld seams, larger voids were observed. Grinding of the surface after heat treatment caused compressive residual stresses near the surface with a relatively small depth. Fatigue tests were carried out on an FE8 test rig. Eighty-two percent of the calculated rating life for conventional bearings was achieved. A high failure slope of the Weibull regression was determined. A relationship between the weld defects and the fatigue behavior is likely. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Investigations on Tailored Forming of AISI 52100 as Rolling Bearing Raceway

Hybrid cylindrical roller thrust bearing washers of type 81212 were manufactured by tailored forming. An AISI 1022M base material, featuring a sufficient strength for structural loads, was cladded with the bearing steel AISI 52100 by plasma transferred arc welding (PTA). Though AISI 52100 is generally regarded as non-weldable, it could be applied as a cladding material by adjusting PTA parameters. The cladded parts were investigated after each individual process step and subsequently tested under rolling contact load. Welding defects that could not be completely eliminated by the subsequent hot forming were characterized by means of scanning acoustic microscopy and micrographs. Below the surface, pores with a typical size of ten µm were found to a depth of about 0.45 mm. In the material transition zone and between individual weld seams, larger voids were observed. Grinding of the surface after heat treatment caused compressive residual stresses near the surface with a relatively small depth. Fatigue tests were carried out on an FE8 test rig. Eighty-two percent of the calculated rating life for conventional bearings was achieved. A high failure slope of the Weibull regression was determined. A relationship between the weld defects and the fatigue behavior is likely

ESPRAS Survey: National and European Societies for Plastic Surgeons ESPRAS Umfrage: Nationale und europ ische Gesellschaften f r Plastische Chirurgie

Background The European Society of Plastic, Reconstructive and Aesthetic Surgery (ESPRAS) comprises 40 national societies across Europe. In addition to ESPRAS, there are 8 different European Plastic Surgery societies representing Plastic Surgeons in Europe. The 4 thEuropean Leadership Forum (ELF) of ESPRAS, held under the motto Stronger together in Europe in Munich in 2023, aimed to collect and disseminate information regarding the national member societies of ESPRAS and European societies for Plastic Surgeons. The purpose was to identify synergies and redundancies and promote improved cooperation and exchange to enhance coordinated decision-making at the European level. Material and methods An online survey was conducted regarding the organisational structures, objectives and challenges of national and European societies for Plastic Surgeons in Europe. This survey was distributed to official representatives (Presidents, Vice Presidents and General Secretaries) and delegates of national and European societies at the ELF meeting. Missing information was completed using data obtained from the official websites of the respective European societies. Preliminary results were discussed during the 4 thELF meeting in Munich in March 2023. Results The ESPRAS survey included 22 national and 9 European Plastic Surgery societies representing more than 7000 Plastic Surgeons in Europe. Most national societies consist of less than 500 full members (median 182 members (interquartile range (IQR) 54-400); n=22). European societies, which covered the full spectrum or subspecialities, differed in membership types and congress cycles, with some requiring applications by individuals and others including national societies. The main purposes of the societies include research, representation against other disciplines, specialisation and education as well as more individual goals like patient care and policy regulation. Conclusion This ESPRAS survey offers key insights into the structures, requirements and challenges of national and European societies for Plastic Surgeons, highlighting the relevance of ongoing close exchange between the societies to foster professional advancement and reduce redundancies. Future efforts of the ELF will continue to further explore strategies for enhancing collaboration and harmonisation within the European Plastic Surgery landscape

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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