Variational Formulation for Frictional Interface Dynamics

2012 ◽  
Author(s):  
Timothy Truster ◽  
Arif Masud ◽  
Lawrence A. Bergman
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Coulomb Friction ◽  
Bolted Joints ◽  
Lap Joint ◽  
Stick Slip ◽  
Element Simulation ◽  
Friction Models ◽  
Frictional Interface ◽  
Current Emphasis

The dynamic response of component bolted joints often plays a significant role in the overall behavior of a structural system. Accurate finite element simulation of these problems requires proper treatment of the interface conditions. We present a formulation carefully suited to these problems that incorporates discontinuous Galerkin (DG) treatment locally at the interface. The present work is an extension of our previous investigations of friction models within a finite element method for quasi-static problems. The current emphasis is on the treatment of the inertial term and ensuring that artificial resonance is not induced by the discrete interface. The weak imposition of continuity constraints allows the stick-slip behavior at the jointed surface to proceed smoothly, reducing the numerical instability compared to node-to-node contact techniques. As a model problem, we simulate the dynamic response of a lap joint subjected to an impulse axial force assuming Coulomb friction at the interface.

Asperity Spring Friction Model With Application to Belt-Drives

2003 ◽  
Author(s):  
Tamer M. Wasfy
Keyword(s):  
Finite Element ◽  
Coulomb Friction ◽  
Friction Model ◽  
Belt Drive ◽  
Finite Element Code ◽  
Time Step ◽  
Stick Slip ◽  
Normal Contact ◽  
Belt Drives ◽  
Coulomb Friction Model

An asperity spring friction model that uses a variable anchor point spring along with a velocity dependent force is presented. The model is incorporated in an explicit timeintegration finite element code. The friction model is used along with a penalty-based normal contact model to simulate the dynamic response of a two-pulley belt-drive system. It is shown that the present friction model accurately captures the stick-slip behavior between the belt and the pulleys using a much larger time-step than a pure velocity-dependent approximate Coulomb friction model.

Analysis of Dynamic Response for Piezoelectric Vibration Converter by Finite Element Simulation

2007 ◽  
Vol 336-338 ◽  
pp. 335-337
Author(s):  
Xiang Cheng Chu ◽  
Ren Bo Yan ◽  
Wen Gong ◽  
Long Tu Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Elements ◽  
Dynamic Response ◽  
Finite Element Modeling ◽  
Three Dimensions ◽  
Dynamic Motion ◽  
Element Simulation ◽  
Piezoelectric Coupling ◽  
Piezoelectric Vibration

The dynamic behavior of a vibration converter of an ultrasonic motor is described using finite element method. Tetrahedral finite elements with three dimensions are formulated with the effects of piezoelectric coupling. And the solution of the coupled electroelastic equations of dynamic motion is presented. The simulated response of the vibration converter is calculated, and shows excellent consistency with experimental results, which proved that finite element modeling is a good approach to optimize piezoelectric apparatus design. A gradual optimized method is employed to ascertain the most compatible structure.

Finite Element Model of Schallamach Waves in Belt-Drives

2019 ◽  
Author(s):  
Mohammed Khattab ◽  
Tamer Wasfy
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Finite Element Model ◽  
Wave Phenomenon ◽  
Coulomb Friction ◽  
Element Model ◽  
Belt Drive ◽  
High Fidelity ◽  
Stick Slip ◽  
Belt Drives

Abstract The objective of this study is to investigate if a high-fidelity finite element model can predict the Schallamach wave phenomenon in belt-drives. To this end a computational model which closely mimics a recently developed one-pulley experimental belt-drive apparatus, was created. The dynamic response predicted by the model is compared to the experiment results in order to demonstrate that the model can be used to predict the Schallamach wave phenomenon. Furthermore, the model is used to investigate the roles of Coulomb friction coefficient, adhesion, and torque direction on stick-slip instability effects.

Finite Element Modeling of Structures With L-Shaped Beams and Bolted Joints

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
K. He ◽  
W. D. Zhu
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Predictive Modeling ◽  
Natural Frequencies ◽  
Model Updating ◽  
Bolted Joints ◽  
Beam Model ◽  
Bolted Connection ◽  
Modeling Approach ◽  
Global Dynamic

Due to bending-torsion coupled vibrations of the L-shaped beams and numerous uncertainties associated with the bolted joints, modeling structures with L-shaped beams and bolted joints is a challenging task. With the recent development of the modeling techniques for L-shaped beams by the authors (He and Zhu, 2009, “Modeling of Fillets in Thin-Walled Beams Using Shell/Plate and Beam Finite Elements,” ASME J. Vibr. Acoust., 131(5), p. 051002), this work focuses on developing new finite element (FE) models for bolted joints in these structures. While the complicated behavior of a single bolted connection can be analyzed using commercial FE software, it is computationally expensive and inefficient to directly simulate the global dynamic response of an assembled structure with bolted joints, and it is necessary to develop relatively simple and accurate models for bolted joints. Three new approaches, two model updating approaches and a predictive modeling approach, are developed in this work to capture the stiffness and mass effects of bolted joints on the global dynamic response of assembled structures. The unknown parameters of the models in the model updating approaches are determined by comparing the calculated and measured natural frequencies. In the predictive modeling approach, the effective area of a bolted connection is determined using contact FE models and an analytical beam model; its associated stiffnesses can also be determined. The models developed for the bolted joints have relatively small sizes and can be easily embedded into a FE model of an assembled structure. For the structures studied, including a three-bay space frame structure with L-shaped beams and bolted joints, and some of its components, the errors between the calculated and measured natural frequencies are within 2% for at least the first 13 elastic modes, and the associated modal assurance criterion values are all over 94%.

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