Table 3.

Main failures of smartphones, affected parts and failure and degradation mechanisms.

Part	Main failures	Failure and degradation mechanisms
Display	Display glass cracked, scratched, splintered	Accidental drops or other mechanical stresses (shocks, vibrations)
	LCD failure: black screen, broken/dead pixels, no background light
	The touchscreen does not respond as expected
Back cover	Breakage (e.g. cracks, scratches)	Accidental drops or other mechanical stresses (shocks, vibrations)
Battery	Loss of performance	Aging of the battery
	Battery not charging	External power supply/charging port/battery connection failure
	Overheating	Increased internal resistance
Operating System	Malfunctioning/loss of security and performance	Software, OS and/or security updates not available Lack of sufficient capacity (memory) or performance (low RAM, outdated SoC)
Electronics	Short circuits, disconnection of parts	Stress conditions (e.g. water and dust exposure, shocks, vibration)