Integrated Tribological Analysis within a Multi- physics Approach to System Dynamics

For life cycle analysis of any component of a system realistic operating conditions under short or long transience are required. Therefore, the desired approach would be an integrated system approach, in which the behaviour tribological conjunctions should be incorporated. This approach necessarily includes many interacting physical phenomena, the integrated inclusion of which is referred to as a multi-physics framework. The framework comprises a hierarchical structure, in which the interacting phenomena take place across the physics of scale. These will usually include large rigid body motions such as crankshaft rotation, valve motion and piston primary translational motion in IC engines. It also encompasses structural vibration of elastic members, manifested by their compliance or modal behaviour, such as thermoelastic distortion of piston skirt (of the order of several tens of micrometer to tenths of millimeter), as well as contact deformation of contiguous solids and lubricant film formation in micro-scale. The paper shows that improved computational power and refined numerical techniques have paved the way for the simultaneous solutions of these interacting physics within one analysis. This approach can lead to very detailed, but time-consuming outcomes. Alternatively sufficient amount of detail may still be obtained with reduced modelling features with good degree of accuracy, and in accord with experimental observations. The paper primarily deals with the use of multi-physics approach in piston and valve train systems.