Pure Elastic Contact Force Models

2016 ◽  
pp. 15-25
Author(s):  
Paulo Flores ◽  
Hamid M. Lankarani
Keyword(s):  
Contact Force ◽  
Elastic Contact

scholarly journals Strain Hardening From Elastic–Perfectly Plastic to Perfectly Elastic Flattening Single Asperity Contact

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Hamid Ghaednia ◽  
Matthew R. W. Brake ◽  
Michael Berryhill ◽  
Robert L. Jackson
Keyword(s):  
Finite Element ◽  
Contact Force ◽  
Material Model ◽  
Real Contact Area ◽  
Contact Radius ◽  
Elastic Contact ◽  
Elastic Deformations ◽  
Real Contact ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

For elastic contact, an exact analytical solution for the stresses and strains within two contacting bodies has been known since the 1880s. Despite this, there is no similar solution for elastic–plastic contact due to the integral nature of plastic deformations, and the few models that do exist develop approximate solutions for the elastic–perfectly plastic material model. In this work, the full transition from elastic–perfectly plastic to elastic materials in contact is studied using a bilinear material model in a finite element environment for a frictionless dry flattening contact. Even though the contact is considered flattening, elastic deformations are allowed to happen on the flat. The real contact radius is found to converge to the elastic contact limit at a tangent modulus of elasticity around 20%. For the contact force, the results show a different trend in which there is a continual variation in forces across the entire range of material models studied. A new formulation has been developed based on the finite element results to predict the deformations, real contact area, and contact force. A second approach has been introduced to calculate the contact force based on the approximation of the Hertzian solution for the elastic deformations on the flat. The proposed formulation is verified for five different materials sets.

A Realistic Model for Visco-Elastic Contact Between Spherical Particles

2006 ◽  
Author(s):  
Mohammad Hadi Bordbar ◽  
Timo Hyppanen
Keyword(s):  
Finite Elements ◽  
Contact Force ◽  
Coefficient Of Restitution ◽  
Spherical Particles ◽  
Experimental Result ◽  
Size Difference ◽  
Force Model ◽  
Elastic Contact ◽  
Contact Force Model ◽  
Finite Elements Model

The contact force model is very important to describe the grain collision process accurately. In this research, the linear/nonlinear contact force models and normal coefficient of restitution in different impact velocities has been studied. A new contact force model for describing the normal collision between two visco-elastic spherical particles has been suggested and the ability of this new model in predicting the correct behavior of normal contact has been confirmed. The constitutive equations of this model have been solved numerically and the result shows a better conformity with experimental result reported by Bridge et al. [1] than the previous models, such as the model presented by Brilliantov et al. [2]. By using the suitable finite elements model, the stress and deformation of particles during the collision has been obtained and the result of the finite elements model shows a good conformity with our new suggested contact force model in the case of elastic and visco-elastic contact. The behavior of normal coefficient of restitution in multisize spherical particles in different impact velocities and effect of the size on it has been experimentally studied. In addition to our more suitable contact force model, we achieved some nice conclusions from our experimental data about the loss of energy during the multisize collision and effect of size difference on this loss.

Study on Contact Force of Tooth Profile Modification

2011 ◽  
Vol 328-330 ◽  
pp. 451-456
Author(s):  
Yong Ma ◽  
Qi Huang ◽  
Zhi Feng Lou ◽  
Ke Hong Li
Keyword(s):  
Finite Element ◽  
Dynamic Simulation ◽  
Contact Force ◽  
Equivalent Stress ◽  
Finite Element Models ◽  
Contact Method ◽  
Elastic Contact ◽  
Profile Modification ◽  
Single Tooth ◽  
Contact Impact

Linear, conic, cubic, and sine relief curve are compiled and established in MATLAB, on which gear models are built in UG and a new method of establishing relief gear models is proposed in this paper. Based on the theory of elastic, contact method is used on the proposed finite element models of gears by software LS-DYNA. Total contact force of teeth face, contact force of single tooth and equivalent stress on relief gears in different cases are obtained. The results show that contact impact existing in meshing between teeth of gears is ameliorated, contact force of tooth face and equivalent stress is reduced. The effect of cubic and sine relief curve is the best. So dynamic simulation on relief gears has great significance for reducing contact force between teeth faces of gears.

Fracture Reasons and Improvements for the Running Gear of Shearers

2012 ◽  
Vol 490-495 ◽  
pp. 2733-2737
Author(s):  
Chun Yu Song ◽  
Jing Ru Liu ◽  
Xiu Juan Zhang
Keyword(s):  
Finite Element ◽  
Internal Stress ◽  
Contact Force ◽  
Maximum Stress ◽  
Contact Analysis ◽  
Finite Element Models ◽  
Elastic Contact ◽  
Gear Teeth ◽  
Calculation Results ◽  
Contact Spots

Running traction mechanism of shearers is adopted as the analysis object in this paper. The finite element models for the elastic contact analysis between the running gears and pin-rails are created. When the gears are running, the variation principles of contact spots, contact force, and internal stress for the gears and pin-rails at the different contact positions are analyzed. The calculation results show that the maximum stress is located at the edges of the gear teeth for the different contact positions. When the teeth are loaded with the repeated large stress, cracks are produced at the tooth edges at first and then are growing. The tooth breakage is produced at last. Gear chamfers using two circulars at the tooth edges can change the location of the maximum stress and the maximum MISES stress can be reduced by 20% or more. Therefore, the fracture problem of gear teeth is solved basically.

scholarly journals Estimation And Compensation of Angular Misalignment At Robot End Brush Roller - Workpiece Contact Interface Via Elastic Contact Force Perception

2021 ◽  
Author(s):  
Xiaozhi Feng ◽  
Rui Lv ◽  
Chen Qian ◽  
Yudi Wang ◽  
Linli Tian ◽  
...  
Keyword(s):  
Contact Force ◽  
Error Compensation ◽  
Large Scale ◽  
Machining Process ◽  
Elastic Contact ◽  
Contact Interface ◽  
Angular Misalignment ◽  
Force Perception ◽  
Robotic Grinding ◽  
Control Command

Abstract When the non-standard customized brush roller tool is used for robotic grinding of large-scale components, the clamping and positioning error of the brush roller at the end of the robot is extremely easy to cause misalignment at the brush roller - workpiece contact interface, which will affect the machining accuracy and surface quality. In order to ensure the parallel contact between the brush roller and the workpiece surface during the machining process, a calculation model of the angular misalignment at the brush roller - workpiece contact interface is proposed based on the elastic contact force perception, and then the accurate positioning of the robot end brush roller is realized by a fast compensation method. Firstly, according to the geometric force relationship between the brush roller and the workpiece, as well as the determined brush roller material properties parameters, the estimation model of angular misalignment is established. Secondly, both the axial force and normal torque at the time of initial contact detected by the force-controlled sensor are regarded as the input parameters in the model. Further, the calculated brush roller - workpiece contact offset is used as the geometric error compensation amount, and the brush roller is deflected to achieve error compensation by the robot RAPID program control command. The finite element simulation results are compared with the theoretical calculation values, and the average relative error is 15.1%. The experiment on robotic grinding and brushing of high-speed rail body indicates that the compensated angle can be reduced to 0.024° from an average of 0.179° before compensation, coupled with uniform material removal depth. The proposed method can significantly improve the contour accuracy of large-scale components.

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