The Relationship of a Gasket’s Physical Properties to the Sealing Phenomenon 650431
The internal combustion engine cylinder head gasket is the most complex of all gasket applications. This is due to the variety of seals and sealing conditions which must be achieved in a single gasket. Some of the physical characteristics studied for such gaskets include spring rate, stress relaxation, torque loss, and permeability of current materials and elements used in these constructions. The effects of temperature, sealing stress, thickness, geometry, and engine operation on the properties of gaskets are discussed.
In one of the theoretical derivations given, a mathematical model of a viscoelastic material is used to explain the results of certain experimental testing. Major emphasis is placed on spring rate and stress relaxation, which are directly related to fluctuations of sealing pressure and loss of torque which must be controlled in order to achieve satisfactory sealing.