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Cylinder Head Gasket Fretting Simulation for High Horse Power Engine
Abstract:
The head gasket of an internal combustion engine acts as a critical seal between its cylinder block and heads. Typically, and ideally, a high horse power engine head gasket will be composed of elastomer fluid sealing elements in a carrier and combustion seal body composed of aluminum, brass, carbon steel, copper, nickel, and/or stainless steel etc. The head gaskets purpose is to seal high pressure combustion gases, coolant, and oil and to ensure no leakage of gases or fluids out of the block to head joint.
Three major failure modes [1] for cylinder head gasket joint are; 1. Fluid or gas leakage due to low sealing pressure. 2. Head gasket (bead) cracking due to high gap alternation and 3. Gasket scrubbing/fretting due to pressure and temperature fluctuations causing relative movement in the joint. During engine operation, the head gasket design should be robust enough to prevent all failure modes and provide acceptable performance. Sealing analysis method to address low sealing pressure failure mode is well developed and common within the industry. This paper is focused on the development and utilization of an analytical method for the 3rd failure mode mentioned above i.e., scrubbing/fretting. Single layer metal gasket is considered during the scope of mentioned method. Single layer metal gasket gets locally yielded due to the design feature provided on the cylinder liner, called as bite ring.
During the scope of work, head gasket fretting mechanism is investigated. Based on the understanding of the fundamental fretting mechanism, considering Ruiz model [2], an analysis procedure is developed and finite element analysis results are correlated with actual failures and measured data. Finite element analysis results shows very good correlation in terms of relative sliding magnitude and failure location prediction. Commercial software ANSYS is used here. Actual gasket crushing is simulated by using 3D solid elements with non-linear material and geometric non linearity captured.