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https://hdl.handle.net/10216/153531| Author(s): | Maria José Pires Ribas |
| Title: | Fracture energy assessment of polyurethane adhesives [The influence of mode mixity, loading rate, and temperature] |
| Issue Date: | 2023-09-25 |
| Abstract: | Accordingly, the aim of the current work is to experimentally analyze the interactions of mode mixity and temperature on the fatigue behaviour of adhesives used in vehicle structures and electronic devices. For the fatigue characterization of the adhesive and the bi material interfaces as a function of temperatures they will be subjected to different loading modes (including pure mode I, pure mode II, and mixed mode) each tested at three temperatures including room temperature, very low temperature (-30 oC) and high temperature (+60 oC). The rate of fatigue crack growth will be experimentally analyzed in a displacement control fatigue test for adhesive joints. |
| Description: | The main goal of this study is to experimentally analyze the influence of service temperature on the fatigue threshold and fatigue crack growth rate of adhesives used in the automotive industry. During their service life, adhesive joints are often subjected to cyclic loadings. In this condition, a fatigue crack can initiate and propagate due to fatigue damage along the bondline of the two bonded substrates. To design such structures against cyclic loading, the fatigue threshold energy and fatigue crack growth rate should be carefully analyzed by the joint designer based on a safe life (using the threshold energy) or damage tolerance (using the crack growth rate results) concepts. Several parameters affect the fatigue life of such structures e.g. environmental conditions, mean stress, substrate material, etc. Among them, ambient temperature is one of the key factors that can severely change the results specially for adhesive joints. On the other hand, in real practice bonded assemblies are often subjected to mixed mode stress state that makes the analysis more complicated. In these conditions, to avoid a catastrophic fatigue failure, estimation of the fatigue behaviour of bondlines is of prime importance. However, fatigue crack growth along the bondlines has been less considered by researchers. To address this research gap, in this study the effects of service temperature on the fatigue crack initiation and fatigue crack propagation of different adhesives will be experimentally investigated. |
| Subject: | Engenharia mecânica Mechanical engineering |
| Scientific areas: | Ciências da engenharia e tecnologias::Engenharia mecânica Engineering and technology::Mechanical engineering |
| DOI: | 10.34626/9g74-wq38 |
| TID identifier: | 203425766 |
| URI: | https://hdl.handle.net/10216/153531 |
| Document Type: | Dissertação |
| Rights: | openAccess |
| Appears in Collections: | FEUP - Dissertação |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 647016.pdf | Fracture energy assessment of polyurethane adhesives [The influence of mode mixity, loading rate, and temperature] | 56.32 MB | Adobe PDF |  View/Open |
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