University of Twente Student Theses


Design of new test setups for characterization experiments of adhesives

Blaauw, Jurjen (2019) Design of new test setups for characterization experiments of adhesives.

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Abstract:In order to simulate the brittle failure of an adhesive, the material properties of this adhesive must be known. For this, many so-called single lap joints must be made and tested. Currently, the adhesive layer thickness of the joints is controlled by placing spacer wires within the adhesive. However, this might influence the results as the wire might introduce nucleation points for cracks. In this report, the development process of a new jig to effectively and accurately produce single lap joints without spacer wire is discussed. This new concept is compared with the existing methods to produce the single lap joints. In total, three iterations of this jig are developed. Using these new jigs, experiments have been performed to determine the material properties of an epoxy adhesive. The influence of different overlap lengths and adhesive layer thicknesses of the joint is tested. The samples made with the new jig are compared with similar samples made with the traditional method using spacer wires. Furthermore, the influence of the fillet and curing method is investigated and discussed. Besides the tests with the single lap joint, three other projects are discussed in this report. First, a method has been tested that can produce bulk specimens of epoxy-based adhesives. Results and possible improvements of this method are discussed. Second, a Matlab tool has been developed to simulate the internal forces within a single lap joint's adhesive layer. The development process, including further improvements, are treated in the report. Finally, two different tests with ductile silicone adhesive are executed. In the first experiment, the internal hydrostatic tension created due to thermal contraction of the adhesive is estimated. In the second experiment, the nucleation and growth of cavity bubbles during cooling down of the adhesive is followed.
Item Type:Essay (Master)
Robert Bosch GmbH, Renningen, Germany
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
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