Analysis of energy loss on friction in carving connection of rods using of hysteresis diagrams

摘要

The diversity of factors influencing connection work determines difficulty of analytic definition powers of elastic and unelastic resistance at dynamic loadings. Therefore the nature of change of these forces was researched at quasi-statical loading of rod connections on the special test bench. The test bench allowed taking a photograph of hysteresis diagrams in coordinates of "force-displacement" from the electronic oscillograph screen using a photographic camera. Four types of rod connections were accepted for researches - one nipple and three box coupling. Taking into account that there is a multiple change of deformation sign during an impact impulse distribution along the rods the deformation wave practically fades by the next impact. Hysteresis diagrams are photographed in "squeeze-distension" conditions. Experiments achieved that unelastic resistance force in box coupling constantly increases with twisting moment extension and vice versa, it has strongly pronounced maximum value in nipple connection. So it is obvious to connect rods by nipple latented inside two connecting rods. Knowing a general rigidity of connection, threading parts rigidity and connecting element rigidity of the contact rigidity of connection was appointed. If a twisting moment increases the contact rigidity of the connection increases too, changing the parabolic law. So if the contact rigidity increases the rod displacement decreases relatively with the connecting element (a work of friction decreases). Consequently the loss coefficient decreases too. So a rational selection of connecting elements rigidity allows raising a coefficient of impulse energy transmission along rods and an efficacy of using a boring machine.