A Novel Ontology Approach to Support Design for Reliability considering Environmental Effects

Table 3

Rubber seals FMEA analysis (applying environmental effects ontology).

Product	Function	Environmental load	Failure mode	Cause	Failure mechanism
Rubber seal	Seal	Salt spray, dust	Fracture, cuts uneven local	Mechanical injury	Salt enters into space between seal ring and other structures and results in wear of seal ring in the relative movement
				Ageing
		Solar radiation, oxygen (ozone)	Hard cracking, sticky, brittle	Photooxidation; aging	Rubber macromolecules decompose due to the absorption of photons, and molecular bond is oxidized under the action of oxygen
		High temperature, oxygen (ozone)		Thermal aging	Rubber macromolecules decompose due to the absorption of heat, and molecular bond is oxidized under the action of oxygen
		Precipitation, condensation		Absorbent; hydrolyzed	Deliquescence of rubber molecules due to absorbing moisture
		Microbe, humidity, temperature		Mildew	In suitable environment, microorganism grows and breeds in the rubber, thereby reducing material properties
		Air pollutant	Leak, break	Corrosion	Ozone and other oxidants can oxidize rubber molecules bond
		Low pressure		Deformation	Unequal internal and external pressure make rubber seal deformation
		Ozone (with stress)		Ozone-induced cracking	Rubber seal oxidized by ozone was stressed