Dr.-Ing.

Albrecht, Stefan

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  • Publication
    Consideration of reliability and sustainability in mechanical and civil engineering design to reduce oversizing without risking disasters
    ( 2022)
    Dazer, Martin
    ;
    Ostertag, Andreas
    ;
    Herzig, Thomas
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    Borschewski, David
    ;
    Albrecht, Stefan orcid-logo
    ;
    Bertsche, Bernd
    Technical systems have to be designed that the requirements regarding service life are met with high reliability to ensure safe product operation. In many cases, the design is still based on single events, such as extreme load levels and additional safety factors, in order to ensure reliability, which is accompanied by a high degree of oversizing. This means that significantly more resources are consumed than actually needed in order to ensure the reliability requirement. To prevent reliability from being ensured solely by oversizing, reliability criteria must be supplemented by the claim for sustainability starting with the product design. On the one hand, profound reliability considerations make safety factors obsolete. On the other hand, oversizing is limited by the claim for sustainability. The overall result is a sustainable design while ensuring reliability at the same time. Within this work, two case studies from two different industrial sectors are introduced to show the trade-off in which the design has to be developed and how an overall solution proposal can look like. In both case studies, the savings in terms of resources and greenhouse gases emitted are shown while considering reliability and sustainability during the product design phase.
  • Publication
    Reliable design of adaptive load-bearing structures with focus on sustainability
    ( 2020)
    Ostertag, Andreas
    ;
    Dazer, Martin
    ;
    Bertsche, Bernd
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    Schlegl, Friederike
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    Albrecht, Stefan orcid-logo
    ;
    Leistner, Philip
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    Gienger, Andreas
    ;
    Wagner, Julia
    ;
    Tarín, Cristina
    ;
    Sawodny, Oliver
    Nowadays large amounts of raw materials are used in the building industry. Conventional design methods for passive constructions are at the limit of what's permissible according to standard and oversized for most of their design life. In order to reduce the consumption of raw material and the environmental impact caused by its production, an actuation of the load-bearing structure is a possible way forward. Such a structure is able to adapt to different load cases by specifically manipulating internal stresses using actuators installed in the structure. This paper introduces a design procedure applied to an adaptive high-rise load-bearing structure demonstrating reliability and includes the changing environmental impact. The trade-off between oversizing, which leads to high reliability and savings of raw material for minimal environmental impact needs to be solved for unique structures with quantity one. By use of a linear-elastic model the effect of wind loads is simulated and actuator forces and tensions were calculated. In the total balance the energy consumption of the actuators and its related greenhouse gas emissions as well as the intended savings due to the reduced need for raw materials in production is included. In conclusion, replacing building material with energy can be a promising way forward on the condition, that electric energy will become increasingly environmentally friendly in the near future, whereas natural resources for materials are limited.