The Theory of Sound, Two Volumes In One

Contact modeling is still one of the most difficult aspects of nonlinear implicit structural analysis. Most 3D contact algorithms employed today use node-on-segment approaches for contacting dissimilar meshes. Two pass node-on-segment contact approaches have the well known deficiency of locking due to over constraint. Furthermore, node-on-segment approaches suffer when individual nodes slide out of contact at contact surface boundaries or when contacting nodes slide from facet to facet. This causes jumps in the contact forces due to the discrete nature of the constraint enforcement and difficulties in convergence for implicit solution techniques. In a previous work, we developed a segment-to-segment contact approach based on the mortar method that was applicable to large deformation mechanics. The approach proved extremely robust since it eliminated the overconstraint which caused ''locking'' and provided smooth force variations in large sliding. Here, we extend this previous approach in to treat frictional contact problems. The proposed approach is then applied to several challenging frictional contact problems which demonstrate its effectiveness.

A Mortar Segment-to-Segment Frictional Contact Method for Large Deformations

This textbook compiles reports written by about 35 internationally recognized authorities, and covers a range of interests for geotechnical engineers. Topics include: fundamentals for mechanics of granular materials; continuum theory of granular materials; and discrete element approaches.

Mechanics of granular materials : an introduction

A review of fretting study on nuclear power equipment

Validity diagrams of statistical energy analysis

An energy approach for impact wear in water environment

Introduction of acoustical diffraction in the radiative transfer method

Recent years have witnessed the development of so-called relaxation tribometers, the free oscillation of which is altered by the presence of frictional stresses within the contact. So far, analysis of such oscillations has been restricted to the shape of their decaying envelope, to identify in particular solid or viscous friction components. Here, we present a more general expression of the forces possibly acting within the contact, and retain six possible, physically relevant terms. Two of them, which had never been proposed in the context of relaxation tribometry, only affect the oscillation frequency, not the amplitude of the signal. We demonstrate that each of those six terms has a unique signature in the time-evolution of the oscillation, which allows efficient identification of their respective weights in any experimental signal. We illustrate our methodology on a PDMS sphere/glass plate torsional contact.

https://hal.archives-ouvertes.fr/hal-02112244/document

Relaxation Tribometry: A Generic Method to Identify the Nature of Contact Forces

Statistical Energy Analysis is a statistical method in vibroacoustics entirely based on the application of energy balance that is the first principle of thermodynamics. In this study, the definition of vibrational entropy is introduced for sub-systems containing energy and modes. The rate of entropy production at interfaces between sub-systems is also derived. Finally, in steady-state condition, an entropy equilibrium is reached. The meaning of entropy and some implications of this entropy balance are also discussed.

/pdf/statistical-energy-analysis-and-the-second-principle-of-3bb4qibasd.pdf

Statistical Energy Analysis and the second principle of thermodynamics

Recent years have witnessed the development of so-called relaxation tribometers, the free oscillation of which is altered by the presence of frictional stresses within the contact So far, analysis of such oscillations has been restricted to the shape of their decaying envelope, to identify in particular solid or viscous friction components Here, we present a more general expression of the forces possibly acting within the contact , and retain six possible, physically relevant terms Two of them, which had never been proposed in the context of relaxation tribometry, only affect the oscillation frequency, not the amplitude of the signal We demonstrate that each of those six terms has a unique signature in the time-evolution of the oscillation, which allows efficient identification of their respective weights in any experimental signal We illustrate our methodology on a PDMS sphere/glass plate torsional contact

Alain Le Bot

Papers

An energy approach for impact wear in water environment

Introduction of acoustical diffraction in the radiative transfer method

Relaxation Tribometry: A Generic Method to Identify the Nature of Contact Forces

Statistical Energy Analysis and the second principle of thermodynamics

Relaxation Tribometry: A Generic Method to Identify the Nature of Contact Forces