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Highlights • Physically perturbed variations of a bolted lap joint studied. • Modeling independent similarity metrics sought from parameter estimation studies. • The surrogate system hypothesis formulated and applied to the lap-jointed benchmarks. • Hypothesis tested in a multi-objective optimization framework. • Tuned whole-joint patch methods employed for the interfacial modeling. Abstract The main challenges in the design and analysis of jointed structures deal with the prediction of dissipation across bolted interfaces. Since friction is thought to be one of the main mechanisms for this, the current study investigates the utility of frictional parameter identification applied across different structures. Based on recent discoveries, a Surrogate System Hypothesis has been formulated to systematize this: the hypothesis states in brief, that the physical properties of a joint are independent of its structural context. The current work seeks to obtain a better understanding of the underlying systems by evaluating a confidence metric for the hypothesis for a relatively simple set of systems—physically perturbed configurations of the Brake-Reuß Beam. Interfacial friction is modeled using whole jointed patches with distributed hysteretic (Iwan) elements and simulations are conducted using the Quasi-Static Modal Analysis (QSMA) approach to estimate the modal characteristics of the system response (amplitude dependence of natural frequency and dissipation). Posing the estimation as a Multi-Objective Optimization Problem (MOOP) is shown to reveal important features of both the employed constitutive model as well as the structure that is modeled. Consequently, the approach is used to evaluate the epistemic uncertainty inherent in three different friction models. The studies reveal that a confidence metric for the hypothesis can be formulated in such a way that it is nearly independent of the friction constitutive model that is employed. [ABSTRACT FROM AUTHOR]

Bolted connections are ubiquitous in mechanical designs and pose a significant challenge to understanding and predicting the vibration response of assembled structures. The present paper develops a physics-based rough contact model of the frictional interactions within a joint. This model sums over the probable interactions of asperities – defined as locally maximum surface features – to determine the contact forces. Here, the tangential contact forces vary smoothly between sticking and slipping and allow the model to better capture the qualitative trends of experimental amplitude dependent frequency and damping than previous studies. Furthermore, the novel model is generalized to allow for arbitrarily varying normal pressure including potential separation to better represent the interfacial dynamics. This includes developing a new, computationally tractable approximation to the analytical Mindlin partial slip solution for tangential loading of contacting spheres. The results highlight the importance of accurately characterizing the as-built topology of the interface, the plastic behavior of the contacting asperities, the relevant length scale of asperities, and the eccentricity of asperities. A predictive friction coefficient based on plasticity provides a poor match to experiments, so fitting the friction coefficient is also considered. Numerical results are compared to experiments on the Brake-Reuß Beam to assess the predictive potential of the models. While blind predictions over-predict the slip limit, the current model presents a significant improvement in physics-based modeling and highlights areas for ongoing research. • A physics-based model of contact for jointed structures is derived. • A new model is derived to describe tangential contact of spheres under general motion • Sensitivities to plasticity, topology and asperity statistics are investigated. • The model is implemented in a tribomechadynamics framework to make blind predictions. • Sensitivity studies investigate the role of asperity density, orientation, and distribution. • Predictive friction coefficients are needed as current coefficients are inadequate. [ABSTRACT FROM AUTHOR]

• A multi-scale modeling framework bridging micro-surface features and macro-dynamics. • A coupled modal quasi-static solver employed for the dynamic characterization. • Rough contact models used for constitutive modeling with Zero-thickness elements. • Effectiveness of the framework demonstrated through validation with experimental data. A new framework for modeling the dynamics of bolted structures is proposed that considers the nonlinear interfacial modeling of bolted structures using multi-scale traction-based contact constitutive laws implemented through Zero-Thickness Elements (ZTE). Using rough contact theory, it is possible to establish fundamental constitutive relationships with parameters estimated from micro-scale surface scans. Such a model is employed in the framework for a three bolt lap-joint benchmark (the so-called "Brake-Reuß-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. Preliminary studies are conducted to establish correlations of local changes in relevant roughness parameters with predicted local tractions and dissipation fluxes. [ABSTRACT FROM AUTHOR]