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Iron‐based shape memory alloys (Fe‐SMAs) exhibit the particular characteristic of remembering their initial shape after a phase transformation from austenitic to martensitic. This property, along with the high strength and ductility, recommends such materials for strengthening existing structures and designing highly efficient pre‐stressed structural elements. To achieve this, pre‐strained strips or rods made of Fe‐SMA are anchored to a parent structure in the first step. Afterwards, the activation of the Fe‐SMA is triggered through heating, and the material strives to return to its initial shape. Due to the anchoring, a tensile stress is generated in the Fe‐SMA upon cooling back to room temperature, while in the parent structure, a compressive stress field is obtained. The material behaviour of the Fe‐SMA under uniaxial loading is characterized by a rounded stress‐strain relationship without a pronounced yield point, similar to cold‐formed steels. Moreover, in many currently existing applications, the material is used both in the martensitic phase (pre‐strained form before activation) and in the austenitic phase (after activation). This contribution addressed the suitability of the two‐stage Ramberg‐Osgood model for predicting the uniaxial stress‐strain response of the Fe‐SMA. The key parameters were derived based on uniaxial tensile tests and the suitability of the proposed stressstrain curves for use in advanced finite element simulations was emphasized by simulating these tests. [ABSTRACT FROM AUTHOR]

Laminated glass beams are used as structural elements to support transparent roofs or to transfer wind loads acting on transparent facades. However, in case of breakage, laminated glass beams only exhibit a low residual load‐carrying capacity provided by the interlayers. A more efficient solution is to add a filigree ductile reinforcement on the tension side of the laminated glass beams, for instance by adhesive bonding. By these means, the post‐cracking behaviour of the beams and their redundancy can be improved and a ductile failure behaviour can be achieved. Moreover, an additional pre‐stressing of this reinforcement allows increasing the initial glass cracking resistance. Despite their obvious potential, an application of pre‐stressed laminated glass beams in real projects is prevented by the rather complicated necessary procedures for pre‐stressing. This contribution discusses first experimental results on a novel concept for pre‐stressed laminated glass beams with adhesively bonded strips made of an iron‐based shape memory alloy (Fe‐SMA). The pre‐stress can be applied in this case by heating up the Fe‐SMA. The feasibility of the concept is analysed based on results from four‐point‐bending tests on medium‐scale simple, reinforced and pre‐stressed laminated glass beams. [ABSTRACT FROM AUTHOR]

The wire arc additive manufacturing (WAAM) technology in combination with computational design shows a big potential for realising novel force‐flow optimised and material‐efficient connections. This contribution deals with point‐by‐point WAAM, a material deposition strategy that allows to place material precisely where structurally needed or aesthetically desired. This could be applied, among others, for realising a novel optimised type of steel nodes between custom‐oriented profiles, as they occur in freeform steel‐glass grid‐shells. In this paper, the structural behaviour of robotically fabricated straight WAAM steel bars under uniaxial tensile and compressive loading is discussed. The focus is set on the ductility exhibited by such components as well as on the buckling behaviour observed under compressive loading. Experimental tests were conducted, both under tensile and under compressive loading to assess the influence of the irregular geometry on the structural performance. Furthermore, it was studied to what extent a prediction of the ductile structural behaviour, of the compressive load‐bearing capacity and of the post‐buckling behaviour is possible by finite element simulations. This contribution presents and discusses highlights of the obtained results. [ABSTRACT FROM AUTHOR]

Robot‐assisted point‐by‐point wire and arc additive manufacturing is considered a promising technology for optimising the production of metallic connections used in complex nodes, space trusses or grid shells. While mechanical properties of such elements were proved suitable for structural applications, a lack of knowledge exists concerning their durability. We investigate the corrosion performance of low carbon steel bars produced by point‐by‐point wire and arc additive manufacturing. Metallurgical analyses show uniform microstructure along the length of the steel bars. Corrosion initiation tests in simulated atmospheric exposure reveal the influence of geometry on corrosion, in particular, the presence of concave areas. The surface state and postprinting cleaning processes were investigated with microscopy and electrochemical techniques. These experiments indicate a detrimental effect of oxide scales due to the wire and arc additive manufacturing process on the corrosion behaviour of the steel. The results of the study show that special care must be given to the geometry and surface state of wire and arc additively produced low carbon steel components in case of long‐term use. [ABSTRACT FROM AUTHOR]

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Kragträger aus Verbundsicherheitsglas, wie sie bei transparenten Fassaden in der Form von hängenden Glasfinnen eingesetzt werden, sind aufgrund ihrer Schlankheit, der produktionsspezifischen Imperfektionen und der auftretenden Belastungen kippgefährdet. Numerische und analytische Modelle, die für das Stabilitätsverhalten von Einfeldträger aus Glas bereits in der Fachliteratur vorhanden sind, werden für Kragträger untersucht und erweitert. Zusätzlich wird, ausgehend von praxisüblichen konstruktiven Ausführungen, der Einfluss der Einspannung unter Berücksichtigung weicher Zwischenschichtmaterialien wie Thermoplasten oder Kunstharzmörtel analysiert. Stability behaviour of cantilevered beams made of laminated safety glass. Cantilevered beams made of laminated safety glass, as they are used for transparent facades in the form of suspended glass fins, are susceptible to lateral torsional buckling due to their slenderness, imperfections caused by production and the occurring loading. Numerical and analytical models, which already exist for the buckling behaviour of single-span beams made of glass, are analysed and extended for cantilevered beams. Additionally, the influence of the clamped support, by considering the softer intermediate materials like thermoplastics or resin-based grouts, is investigated based on connection details from practice. [ABSTRACT FROM AUTHOR]