Björn Abeln - Academia.edu (original) (raw)

Papers by Björn Abeln

Adhäsion Kleben & Dichten, Dec 1, 2022

The International Journal of Advanced Manufacturing Technology

Structural bonding of batch hot-dip galvanized components poses a particular challenge against th... more Structural bonding of batch hot-dip galvanized components poses a particular challenge against the background of the build-up of the zinc coating in the form of different zinc-iron phases. As part of a research project, parameters influencing the zinc coating, the pre-treatment of the zinc substrate, and the adhesive were investigated with regard to the load-bearing capacity of a bonded joint. The variation of the zinc coatings was achieved by using four different steel grades in combination with four batch galvanizing processes. Therefore, small-scale, thick shear tensile specimens were uniformly fabricated, galvanized, bonded in pairs, and mechanically tested. A second series of tests was aimed at the feasibility of an adhesive bond of batch galvanized, medium-scale components under realistic boundary conditions. The test specimens were produced by varying the surface preparation and the adhesive and tested mechanically to shear failure. The results of both test series show that z...

Durability of Building and Construction Sealants and Adhesives: 7th Volume

Durability of Building and Construction Sealants and Adhesives: 5th Volume

To realize architectural attractive transparent and lightweight constructions bonded hybrid steel... more To realize architectural attractive transparent and lightweight constructions bonded hybrid steel-glass beams have been developed, where flanges of steel and webs of glass are assembled to I-shaped profiles using adhesives. The load-bearing capacity of such beams is governed – apart from the mechanical and strength characteristics of the adherent - by ageing, temperature and creeping. By means of small scale push-out-tests the properties of different adhesive geometries, the influence of the manufacturing process and the general load carrying behaviour of bonded hybrid steel-glass-beams are shown.

Bauingenieur, 2021

Zusammenfassung Der Einsatzbereich geklebter Glaskonstruktion unter Verwendung von Silikonen mit ... more Zusammenfassung Der Einsatzbereich geklebter Glaskonstruktion unter Verwendung von Silikonen mit hyperelastischem Materialverhalten ist aufgrund hoher bauaufsichtlicher Hürden sehr eingeschränkt. Hinsichtlich der Bemessung von Structural Silicone Glazing (SSG) Klebungen ist die Europäische Technische Zulassungsrichtlinie ETAG 002 für Silikon-Klebungen das einzige normative Dokument. Darin wird eine Berechnungsmethode empfohlen, bei der sich die Normalspannungen aus der einwirkenden Kraft über die Klebfläche berechnen, was jedoch als eine grobe Schätzung angesehen werden kann und dazu beiträgt, dass hohe Sicherheitsfaktoren anzusetzen sind. Im Rahmen von FE-Berechnungen zur Bemessung von Klebverbindungen wird das Material des Klebstoffs in der Regel durch hyperelastische Materialmodelle wie Ogden oder Mooney-Rivlin beschrieben. Diese Materialmodelle und ihre Herleitungen sind jedoch komplex und die Bestimmung der Materialparameter wird als aufwändig empfunden. Der Beitrag gibt einen ...

The Journal of Adhesion, 2021

ABSTRACT Steel bridges with orthotropic decks are a common construction method for long-span brid... more ABSTRACT Steel bridges with orthotropic decks are a common construction method for long-span bridges. The type of construction was developed in the 1960s, and the early structures in particular show increasing crack damage. The reasons for this are, on the one hand, design deficiencies and, on the other hand, massively increased traffic loads. Therefore, there is a need for rehabilitation methods that neither weaken the cross-section, like bolted solutions, nor introduce thermal stresses, like welds, but so far there are no reliable and economic alternatives. This paper summarizes the state of the art on possible damage categories of orthotropic bridge slabs and presents a new rehabilitation alternative using bonded steel patches for crack rehabilitation. It is reported from an ongoing research project how to determine numerically the effectiveness of the bonded steel patches. For this purpose, simple analytical calculations are first used to determine the determining factors and to record their influence. Subsequently, nonlinear numerical calculations with the Drucker-Prager material model are used to identify the stress distributions in the bonded joints in order to optimise the patch geometries. To this end a stiffness factor is presented that can be used to classify such patch bonds and categorize them in terms of their effectiveness.

Europace, 2014

Keywords: structural glass Reference EPFL-REPORT-196634 Record created on 2014-02-13, modified on... more Keywords: structural glass Reference EPFL-REPORT-196634 Record created on 2014-02-13, modified on 2016-08-09

ce/papers, 2021

Geklebte Verbindungen haben im Konstruktiven Glasbau ein großes Anwendungspotential. Allerdings s... more Geklebte Verbindungen haben im Konstruktiven Glasbau ein großes Anwendungspotential. Allerdings sind die Vorbehalte gegenüber einem tragenden Einsatz aufgrund der fehlenden Kenntnis des Tragverhaltens noch groß. Zwar ist die Abhängigkeit des Materialverhaltens vom vorherrschenden Spannungszustand neben den Einflüssen aus Temperatur, Belastungsgeschwindigkeit und Belastungsgeschichte prinzipiell geklärt, bisher aber nur schwer quantifizierbar. In diesem Beitrag sollen unter klarer Definition der Randbedingungen die Möglichkeiten einer rechnerischen Prognose vorgestellt werden. Über FEM‐Einheitszellenberechnungen mit dem Ogden‐Modell werden über die Spannungsmehrachsigkeit klebstoffspezifische Steifigkeitsortskurven abgeleitet. Der Vergleich der Ergebnisse mit Versuchen ergibt überaus zufriedenstellende Übereinstimmungen.

adhäsion KLEBEN & DICHTEN, 2008

Im Stahlbau spielt das Kleben als Alternative zu herkommlichen strukturellen Fugetechniken derzei... more Im Stahlbau spielt das Kleben als Alternative zu herkommlichen strukturellen Fugetechniken derzeit trotz vielfaltiger Anwendungsmoglichkeiten noch eine untergeordnete Rolle. Dass aber dieses relativ neue Verfahren im Bauwesen den etablierten Verbindungsmethoden in vielen Fallen wirtschaftlich und technologisch uberlegen ist, lasst sich am Beispiel der geklebten Sandwichfahrbahnplatte fur Strasenbrucken nachweisen.

Stahlbau, 2017

Beim Einsatz geklebter Verbindungen sind verschiedene Gesichtspunkte zu beachten: die Klebstoffsy... more Beim Einsatz geklebter Verbindungen sind verschiedene Gesichtspunkte zu beachten: die Klebstoffsysteme unter Berücksichtigung der Substratwerkstoffe und der Oberflächenzustände, die Bemessung unter Beachtung der permanenten und transienten Einwirkungen sowie die Ausführung. Alle drei Bereiche haben Einfluss auf die Zuverlässigkeit. In puncto Berechnung jedoch wird dem wirklichen mechanischen Verhalten der Klebfuge in der Praxis nicht Rechnung getragen. Die derzeit verwendeten Ingenieurmodelle schlagen auch bei Berücksichtigung von lokalen Spannungsspitzen häufig fehl. Das ist mit ein Grund für sehr hohe Sicherheitsfaktoren. Der vorliegende Artikel erläutert die für den Bauingenieur relevanten Berechnungsansätze. Weiter werden Möglichkeiten diskutiert, wie die Berechnung von hyperelastischem, aber auch elastoplastischem Klebstoffverhalten, basierend auf dem Spannungszustand von energetischen Ansätzen in gewohnte Gleichgewichtsansätze überführt werden können.

ce/papers, 2018

Monitoring installation process and utilisation of glass and hybrid components in structural glas... more Monitoring installation process and utilisation of glass and hybrid components in structural glass has become increasingly important. However, to date, there are no generally accepted standard procedures to evaluate the in-situ stress condition of a built-in glass. With the aid of photoelasticity a qualitative statement of the stress state in the glass can be made. For this reason, a measurement method and a functional model for a mobile device are being developed with which it is possible to measure in-situ and identify stress peaks, for example, due to incorrect assembly of a glass fitting. By supporting finite element method (FEM) simulations it is possible to transfer the qualitative results of photoelastic measurements into quantitative results.

International Journal of Adhesion and Adhesives, 2014

Today in practice, finite element analyses (FEA) are used to design modern structural steel-glass... more Today in practice, finite element analyses (FEA) are used to design modern structural steel-glass facade panels showing multi-side bonded joints with a complex geometry, because no reliable analytical methods are available for calculating such occurring complex multi-axial stress states. However, experiences show great deviations between experimental and numerical results, which may lead on the one hand to significant over-dimensioning, but on the other handmore criticalto unexpected cases of damages. For applications of facade panels with multi-side bonding, mainly hyper-elastic adhesives are used. The aim of this work is to show the possibilities existing hyper-elastic material models provide for specific steel-glass components and where and under which circumstances these in many FE programs given material models fit best the true behaviour observed in large-scale component tests. To this end, three testing levels have been introduced to investigate the adhesives within multi-side bonding. Small-scale tests have been performed to characterise the adhesives and to determine the material model for subsequent FEA. After that component tests with two different loading situations have been performed to investigate both a complex and a simpler stress state within the adhesive. This paper focuses on both component tests and evaluates the results from these tests. For thin glass thicknesses (here 6 mm) the FEA with hyper-elastic material models provide results in very good compliance with the experimental results. When increasing the glass thickness (here 10 and 15 mm) the influences of the non-linear adhesive characteristic to the total structural behaviour decreases, which leads to rather high deviations from the experimental results. & 2014 Elsevier Ltd. All rights reserved. with a higher modulus of elasticity, e.g. polyurethanes, lead to a greater load bearing capacity. Additionally according to the ETAG002, any adhesive joint is only allowed to be carried out in a simple rectangular cross-sectional form. Deviating from such rectangular form, the in this work investigated L-form joint (see Fig. 1), which is often used in practice, is subject to influences from the constraint of the lateral contraction resulting in a complex multi-axial stress state in the adhesive. The constraint of the lateral contraction is caused by the missing opportunity of the adhesive to deform in the transverse direction freely. Usually for the design process these joint geometries are taken as rectangular geometry and validated with a FEA using a hyper-elastic material model. In this work the use of hyper-elastic material models for simulating not only silicone but also polyurethane adhesives is investigated. This paper is worked out in the context of a German national research project named KLAX [2], which deals with adhesively bonded elastic joints in steel-glass facade panels. This project investigates multi-axial stress states within the adhesive layer Contents lists available at ScienceDirect

Stahlbau, 2008

ABSTRACT Despite of wide variety of application bonding as an alternative structural joining tech... more ABSTRACT Despite of wide variety of application bonding as an alternative structural joining technique plays a minor role in steel construction. Though bonding as a rather new technique in civil engineering can not only compete economically and technologically with established joining technologies, but also offers various benefits. In particular potential fields of application arise where technical and economical limits of traditional joining technologies have been achieved. The existing research project makes a contribution to establish adhesive bonding in steel construction. Within the scope of this research project bridge and facade structures are exemplarily chosen for the application of adhesive technology: Chosen to represent the sector of “infrastructural buildings” adhesive bonded sandwich decks for road bridges were designed and tested. Besides design and dimensioning of bonded sandwich elements according to adhesive technology widespread numerical and analytical calculations were carried out. Additionally the structural behaviour and the manufacturing process of the adhesive bonded decks were analysed by means of large and small scale specimens. In bridge constructions the conventional orthotropic bridge decks have reached their limit of applicability. With this new and heavy load bearing, adhesive bonded steel deck these boundaries can overcome. In the field of facade engineering the research was focussed on two prospective applications of the bonding technology. The first application aims on the reinforcement of hollow sections in mullion-transom facades with adhesive bonding. As a second application for adhesive technology in facade engineering an adhesive bonded alternative for fixing trapezoidal steel sheet facades was analysed. The load bearing capacity was experimentally proved. Furthermore the system parameters have been optimized with respect to an increase of ultimate load on the basis of theoretical investigations. In terms of selection and characterization of possible adhesive systems for the application in structural steelwork a representative scope of commercially offered products is available. Besides mechanical characteristics an analysis of the handling and application behaviour of the adhesive systems, which is important in steel construction, was carried out. Particularly this research was focussed on the preparation of surfaces and the influence of corrosion protection methods. In order to satisfy the specification of the building authorities concerning constructions with adhesive technology, monitoring systems were developed within this project. These systems allow for continuous and cost-efficient monitoring of the adhesive joints. In some degree the fabrication of steel structures with bonding techniques requires a rethinking in execution. Here the preparation of the adhesive surfaces is of particular importance. The experiences gained in this project with the fabrication of large components (as the presented bridge deck) reveal that neither the mixing systems nor the facilities to fix the joining partners are sufficient enough. Further production processes in consideration of factory conditions and site construction have to be developed here. In addition it has to be guaranteed that workings are only carried out by trained specialised staff with real-time quality control during production. It has been proved that constructions with adhesive bonding are equal to other joining techniques. Adhesive bonded steel constructions appeared to be feasible and represent a durable construction form when carried out appropriately. A sensible step in future is to point out the potential of adhesive bonding in steel constructions by selected pilot projects, which aims on removing the existing reservations and obstacles concerning structural bonding technologies systematically.