3.2 Durability: accelerated ageing
One of the main scope of durability management is to predict reference service life (RSL) which can be crucial in the design phase as well as for maintenance planning \citep{spagnolo2007}. In this case the main objective was to choose the right material for 3D printing that was feasible to be exposed in Dubai climate. We applied concepts used in the evaluation of RSL in order to select suitable materials for the project and discard the low-performance ones. Accelerated ageing (by means of a climatic chamber) has been employed to understand different materials behavior under hot climate conditions to foresee thermal material expansion, eventual cracks, change in color due to UV rays.
Firstly we conduct an analysis on Dubai climate to characterize tests with realistic assets based on data that we collected online trough "Weather Underground" and "Meteonorm". We calculated Sol-Air Temperatures for the years 2016 and 2017 combining data of global radiation from Meteonorm with maximum daily temperatures from WU. This first study allowed to set a maximum temperature (70°C) that was kept constant in the test as well as RH 90% and UV rays by means of a UV lamp. In this phase it was not considered necessary to induce thermal shocks or implement the system with rain.
The test have been held trough the climatic chamber at LPM (Laboratorio Prove Materiali) for one week (12-19 feb. 2018). The sample dimensions were 8x8x1 cm (except samples 6 in Fig. 4), we also inserted in the chamber some prototypes of the lamellas in different materials.