Brake, Matthew R. W.2020-04-152020-04-152019-082019-08-06August 201Balaji, Nidish Narayanaa. "Multi-Scale Modeling in Bolted Interfaces." (2019) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/108297">https://hdl.handle.net/1911/108297</a>.https://hdl.handle.net/1911/108297The thesis develops a framework for modeling the dynamics of bolted structures in a multi-scale manner. Understanding that most of the challenges faced by the joints community is around the reconciliation of contact response with physical parameters of the system, the current work is an attempt for this reconciliation using properties identified from interfacial scans of the structure. The basic idea of statistical averaging as conducted in rough contact studies is used here for achieving this in a segment-by-segment fashion. Thus, the response characterization may be done in a manner that represents the micro-level asperity distributions while also preserving a meso-level understanding of possible local variations. Since all of these are used, through the framework, for macro-level simulations of the dynamics, the approach links the micro-, meso-, and the macro-length scales (in that order). For the dynamical simulations, a modified modal quasi-static approach is proposed, which is capable of representing amplitude-dependent nonlinear modal characteristics of nonlinear dynamical systems with linear limit cases. Since the fully stuck and the fully slipped cases may be taken as the limit cases, this is well applicable for the cases with frictional contacts. The results for the modified approach are compared with the responses characterized from other time- and frequency-domain approaches for a simple example in order to validate its efficacy. Finally, the approach is applied for a three bolt lap-joint benchmark (the so-called ``Brake-Reu{\ss}-Beam''). Since the characterization of the interface is conducted in a full-field manner on top of a finite element mesh, the framework is also demonstrated to be applicable for conducting full-field micro-scale interface evolution studies. Validating this would enable models with backward-evolutionary dependence (macro- influencing meso- influencing micro-scale attributes). To this end, preliminary statistical studies are conducted to establish and/or understand correlations of local changes in relevant roughness parameters with predicted local tractions and dissipation fluxes.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.Frictional systemsRough contactZero Thickness ElementsSurface CharacterizationBolted JointsThesis2020-04-15