Statistical analysis of the influence of tooth geometry in the performance of a harmonic drive
The objective of this research is to determine the influence of gear tooth geometrical variations in the performance of a double wave harmonic drive through statistical analysis. This work incorporates state of the art analytical and numerical models to evaluate kinematic error, load capacity, bending fatigue strength, and pitting. The geometric variables considered in this study include gear modulus, pressure angle, and tooth correction factor. The statistical analysis follows a three-level full-factorial design of experiments. Nonlinear dynamic simulation is accompanied by finite element analysis to estimate contact and bending stresses. Largest bending fatigue strength is also determined. Results demonstrate that gear modulus is the geometric parameter with prevalent influence on the kinematic error, and pitting life is rather high for all geometric variables considered.
Kinematics and Dynamics of Machinery
Preface Part I Kinematics of Mechanisms Chapter 1 Introduction Chapter 2 Kiinematics Fundamentals Chapter 3 Graphical Linkage Synthesis Chapter 4 Position Analysis Chapter 5 Analytical Linkage Synthesis Chapter 6 Velocity Analysis Chapter 7 Acceleration Analysis Chapter 8 Cam Design Chapter 9 Gear Trains Part II Dynamics of Machinery Chapter 10 Dynamics Fundamentals Chapter 11 Dynamic Force Analysis Chapter 12 Balancing Chapter 13 Engine Dynamics Chapter 14 Multicylinder Engines Chapter 15 Cam Dynamics Appendix A Computer Programs Appendix B Material Properties Appendix C Geometric Properties Appendix D Spring Data Appendix E Equations for Overbalanced Multicylinder Engines Appendix F Answers to Selected Problems Index
Numerical tools applied to power reactor noise analysis
In order to be able to calculate the space- and frequency-dependent neutron noise in real inhomogeneous systems in two-group theory, a code was developed for the calculation of the Green's function (dynamic transfer function) of such systems. This paper reports on the development as well as the test and application of the numerical tools employed. The code that was developed yields the space-dependence of the fluctuations of the neutron flux induced by fluctuating properties of the medium in the two-group diffusion approximation and in a two-dimensional representation of heterogeneous systems, for both critical systems and non-critical systems with an external source. Some applications of these tools to power reactor noise analysis are then described, including the unfolding of the parameters of the noise source from the induced neutron noise, measured at a few discrete locations throughout the core. Other concrete applications concern the study of the space-dependence of the Decay Ratio in Boiling Water Reactors, the noise-based estimation of the Moderator Temperature Coefficient of reactivity in Pressurized Water Reactors, the modeling of the beam- and shell-mode core-barrel vibrations in Pressurized Water Reactors, and the investigation of the validity of the point-kinetic approximation in subcritical systems driven by an external source. In most of these applications, calculations performed using the code are compared with at-power plant measurements. Power reactor noise analysis applications of the above type, i.e. core monitoring without disturbing plant operation, is of particular interest in the framework of the extensive program of power uprates worldwide.