Dynamic analysis of a slider- crank mechanism behavior with two revolute clearance joints

Generally, in dynamical analysis of mechanical systems,joints are considered to be ideal. However, due tofabrication and assembly errors of components, jointclearance is an inevitable issue. This creates frequentcollisions between journal and bearing, thus the stableperiodic behavior of the system becomes chaotic.The contact force due to clearance is modeled by anonlinear spring-damper element which is proposed byLankarani and Nikravesh. In this paper, dynamic behaviorof a slider-crank mechanism with two revolute clearancejoints, at interfaces of the connecting rod with the crankand the slider, is simulated and is compared by the idealcase.By considering the effect of friction between thejournal and the bearing, governing equations of motionfor two cases, named contact and non-contact phases arederived by Lagrangian approach. Using the Poincarésection, the behavior of the system is illustrated in discretespace. It can be shown that for chaotic systems, thenumber of points in this section is infinite. It will beobserved that by increasing the friction coefficient,periodic orbit of the system becomes stable. In this casethe Poincaré map contains finite number of points.

کلیدواژه ها:

Clearance ، contact force ، Poincaré section.