Try accessing the online resource directly, e.g. for Science Direct go to https://www.sciencedirect.com/. Most online resource websites will include a login option. Look for the institutional / Shibboleth login option and select: TU Dublin (login). You may need to select your region before selecting your institution, i.e. before you get an option to select TU Dublin (login) you may need to first select your region: Ireland / Irish Edugate Federation.
If the above method is your preferred method to begin with and it is not working, go to our A-Z list of online resources and try the link there.