During the design process the mechanical engineer faces a challenge: the choice of the tribological parameters. Even most influential technical references offer ranges for the frictional characteristics. An emblematic example is the coefficient of rolling friction (CRF). The handiest solution in establishing the correct value of the CRF for a certain contact is to find it experimentally. One of the methods is the inclined plane manner. The weak point of the method consists in the particularly small values of the slope required to evidence the effect of rolling friction. The present work shows a technique for finding the CRF. The principle of the method consists in considering both the slope of the inclined plane and the torque of rolling friction as unknowns. The two parameters can be established by experimental finding of the acceleration of an axi-symmetric body, both for ascending and descending motions.

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Abstract. The graphical-analytical methods are mentioned as being straightforward and expedite. The paper presents a graphical-analytical method for the kinematical analysis of a mechanism with rotating cam and oscillating flat-face follower. The manner supposes considering the contact point as a separate element of the mechanism and using concurrently the replacing mechanism with lower pairs and the actual mechanism, the relative motions from the contact point of the cam and contact point of the follower, respectively, are established. The methodology is exemplified for an actual case.

Composite materials are used in manufacturing a vast game of products, from usual objects, medical devices, aerospatial parts to military equipment. One of the features considered when a composite material is designed as target aims the energy dissipation with respect to the projectile. The paper presents an improved alternative of a model which is broadly used in the impact of projectile and composite target. The initial model has the weakness that does not present the hysteresis loop. The improvement of the model consists in including a nonlinear damper placed between the projectile and the target, the damping force being simultaneously proportional to the impact velocity and the elastic force. The new model has a hysteresis loop closed in the origin. The proposed model is applied for concrete situations and the results are presented in graphical manner.