Super harmonic nonlinear lateral vibrations of a segmented driveline incorporating a tuned damper excited by non-constant velocity joints

Abstract

Chair of Advisory Committee: Dr. Alan Palazzolo Linear vibration measurement and analysis techniques have appeared to be sufficient with most vibration problems. This is partially due to the lack of proper identification of physical nonlinear dynamic responses. Therefore, as an example, a vehicle driveshaft exhibits a nonlinear super harmonic jump due to nonconstant velocity, NCV, joint excitation. Previously documented measurements or analytical predictions of vehicle driveshaft systems do not indicate nonlinear jump as a typical vibration mode.The nonlinear jump was both measured on a driveshaft test rig and simulated with a correlated model reproduced the jump. Subsequent development of the applied moments and simplified equations of motion provided the basis for nonlinear analysis.The nonlinear analyses included bifurcation, Poincare, Lyapunov Exponent, and identification of multiple solutions.Previous analytical models of driveshafts incorporating NCV joints are typically simple lumped parameter models. Complexity of models produce significant processing costs to completing significant analysis, and therefore large DOF systems iv incorporating significant flexibility are not analyzed. Therefore, a generalized method for creating simplified equations of motion while retaining integrity of the base system was developed. This method includes modal coupling, modal modification, and modal truncation techniques applied with nonlinear constraint conditions. Correlation of resonances and simulation results to operating results were accomplished.Previous NCV joint analyses address only the torsional degree of freedom.Limited background on lateral excitations and vibrations exist, and primarily focus on friction in the NCV joint or significant applied load. Therefore, the secondary moment was developed from the NCV joint excitation for application to the driveshaft system.This derivation provides detailed understanding of the vibration harmonic excitations due to NCV joints operating at misalignment angles.The model provides a basis for completing nonlinear analysis studying the system in more detail. Bifurcation analysis identified ranges of misalignment angles and speeds that produced nonlinear responses. Lyapunov Exponent analysis identified that these ranges were chaotic in nature. In addition, these analyses isolated the nonlinear response to the addition of the ITD nonlinear stiffness.In summary, the system and analysis show how an ITD installed to attenuate unwanted vibrations can cause other objectionable nonlinear response characteristics. v DEDICATION For my Family vi ACKNOWLEDGEMENTS

Nonlinear numerical and experimental study on the second-order torsional and lateral vibration of driveline system connected by cardan joint

“…Xu and Marangoni (1994a, 1994b) derived misalignment forces based on the kinematics of Hooke’s joint and concluded that the unbalance and misalignment excitation of Hooke’s joint produce first- and second-order vibration. Michael and Alan (Browne and Palazzolo, 2009) studied the phenomenon of nonlinear super harmonic jump due to the universal joint excitations on test bench. The secondary moment exciting the driveshaft system is derived with subsequent analysis showing the harmonic and super harmonic excitations.…”

Dynamic Characteristics of a Segmented Supercritical Driveline with Flexible Couplings and Dry Friction Dampers

“…Coupling or universal joints are used to connect the shaft, which can compensate for installation errors. The super harmonic nonlinear lateral vibration effect caused by universal joints subject to misalignment was initially demonstrated by experiments [25,26]. The model and instability region of the universal joint has been presented and simulated, showing the correlation with physical test results [27,28].…”

Nonuniformity of Isometric Properties of Automotive Driveshafts

“…These aspects of considering the automotive driveshafts as quasi-isometric (isometry with nonuniformity) CVJ (homokinetic) transmissions allows for the development of future research in torsional forced vibrations and the bending-shearing vibrations of automotive driveshafts. This starting point in the investigation of the geometric and kinematic isometric nonuniformities of driveshafts opens the door to modeling of the forced torsional dynamic behavior of the driveshafts in the region of nonlinear parametric vibrations as already mentioned in literature [9,[12][13][14] In Figure 14, the geometric nonuniformity isometry for the driveshaft…”

“…What is very strange for this research paper is that it contains only two references: of which one is a self-citation in the same field of dynamic stability of shafts driven through a universal cardan joint. The experimental evidence on the nonuniformity of CVJ driveshaft transmissions is presented and high-lighted by Browne and Palazzolo in the paper [13]. But the most important experimental research on the nonuniformity of geometric and kinematic isometry of CVJ driveshafts was carried out by Steinwede during his PhD thesis [14] (pp.…”