Towards a predictive, physics-based friction model for the dynamics of jointed structures
Towards a predictive, physics-based friction model for the dynamics of jointed structures
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DOI：
10.1016/j.ymssp.2023.110210
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发表时间：
2023
影响因子：
8.4
通讯作者：
J. H. Porter;M. Brake
中科院分区：
文献类型：
--
作者：
J. H. Porter;M. Brake
螺栓联接在机械设计中普遍存在，对理解和预测装配结构的振动响应提出了很大的挑战。本文提出了一种基于物理的关节内摩擦相互作用的粗糙接触模型。该模型对可能的粗糙度相互作用进行求和--定义为局部最大表面特征--以确定接触力。在这里，切向接触力在粘滞和滑动之间变化平稳，使该模型能够比以前的研究更好地捕捉实验幅值依赖频率和阻尼的定性趋势。此外，新的模型被推广到允许任意变化的法向压力，包括势分离，以更好地描述界面动力学。这包括开发一种新的、计算上易于处理的近似解析Mindlin部分滑移解，用于接触球体的切向载荷。研究结果强调了准确描述界面的原始拓扑结构、接触粗糙面的塑性行为、相应的粗糙面长度尺度以及粗糙面的偏心程度的重要性。基于塑性的预测摩擦系数与实验的匹配性较差，因此也考虑对摩擦系数进行拟合。将数值结果与Brake-Reu？梁上的实验结果进行了比较，以评估模型的预测潜力。虽然盲目预测过度预测了滑移极限，但当前的模型在基于物理的建模方面有了重大改进，并突出了正在进行的研究领域。
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.