Influence of normal contact force model on simulations of spherocylindrical particles

AIChE Journal ◽  
2018 ◽  
Vol 64 (6) ◽  
pp. 1986-2001 ◽  
Author(s):  
Rohit Kumar ◽  
Avik Sarkar ◽  
William Ketterhagen ◽  
Bruno Hancock ◽  
Jennifer Curtis ◽  
...  
Keyword(s):  
Contact Force ◽  
Force Model ◽  
Normal Contact ◽  
Normal Contact Force ◽  
Contact Force Model

Experimental Validation of a Volumetric Planetary Rover Wheel/Soil Interaction Model

2013 ◽  
Author(s):  
Willem Petersen ◽  
John McPhee
Keyword(s):  
Contact Force ◽  
Interaction Model ◽  
Contact Model ◽  
Soil Parameters ◽  
Model Parameters ◽  
Force Model ◽  
Normal Contact ◽  
Planetary Rover ◽  
Normal Contact Force ◽  
Contact Force Model

For the multibody simulation of planetary rover operations, a wheel-soil contact model is necessary to represent the forces and moments between the tire and the soft soil. A novel nonlinear contact modelling approach based on the properties of the hypervolume of interpenetration is validated in this paper. This normal contact force model is based on the Winkler foundation model with nonlinear spring properties. To fully define the proposed normal contact force model for this application, seven parameters are required. Besides the geometry parameters that can be easily measured, three soil parameters representing the hyperelastic and plastic properties of the soil have to be identified. Since it is very difficult to directly measure the latter set of soil parameters, they are identified by comparing computer simulations with experimental results of drawbar pull tests performed under different slip conditions on the Juno rover of the Canadian Space Agency (CSA). A multibody dynamics model of the Juno rover including the new wheel/soil interaction model was developed and simulated in MapleSim. To identify the wheel/soil contact model parameters, the cost function of the model residuals of the kinematic data is minimized. The volumetric contact model is then tested by using the identified contact model parameters in a forward dynamics simulation of the rover on an irregular 3-dimensional terrain and compared against experiments.

Experimental Validation of a Volumetric Planetary Rover Wheel/Soil Interaction Model

2015 ◽  
Vol 10 (5) ◽  
Author(s):  
Willem Petersen ◽  
John McPhee
Keyword(s):  
Contact Force ◽  
Interaction Model ◽  
Contact Model ◽  
Soil Parameters ◽  
Model Parameters ◽  
Force Model ◽  
Normal Contact ◽  
Planetary Rover ◽  
Normal Contact Force ◽  
Contact Force Model

For the multibody simulation of planetary rover operations, a wheel–soil contact model is necessary to represent the forces and moments between the tire and the soft soil. A novel nonlinear contact modeling approach based on the properties of the hypervolume of interpenetration is validated in this paper. This normal contact force model is based on the Winkler foundation model with nonlinear spring properties. To fully define the proposed normal contact force model for this application, seven parameters are required. Besides the geometry parameters that can be easily measured, three soil parameters representing the hyperelastic and plastic properties of the soil have to be identified. Since it is very difficult to directly measure the latter set of soil parameters, they are identified by comparing computer simulations with experimental results of drawbar pull tests performed under different slip conditions on the Juno rover of the Canadian Space Agency (CSA). A multibody dynamics model of the Juno rover including the new wheel/soil interaction model was developed and simulated in maplesim. To identify the wheel/soil contact model parameters, the cost function of the model residuals of the kinematic data is minimized. The volumetric contact model is then tested by using the identified contact model parameters in a forward dynamics simulation of the rover on an irregular three-dimensional terrain and compared against experiments.

An Experimental Correction Method for Relative Indentation of Normal Contact

2020 ◽  
Vol 36 (6) ◽  
pp. 971-984
Author(s):  
P. Peng ◽  
C. A. Di ◽  
G. S. Chen
Keyword(s):  
Contact Force ◽  
Input Signal ◽  
Correction Method ◽  
Large Error ◽  
Model Parameters ◽  
Force Model ◽  
Maximum Relative Error ◽  
Normal Contact ◽  
Contact Force Model ◽  
The Impact

ABSTRACTRelative indentation is the input signal estimating contact force model parameters, so the signal is required to have a higher precision to ensure the accuracy of the estimated contact force model parameters. However, in the impact experiment, the vibration displacements in multiple directions are often coupled in the relative indentation, resulting in a large error of the measured relative indentation. This paper presents an experimental correction method for the relative indentation. Firstly, the relative indentation is decoupled by the established model of the spatial position of the hammerhead relative to the sample to reduce the errors caused by the rotation of the pendulum boom and the vibration of the base. A pendulum impact test device is established to verify the correction method of relative indentation. The results show that the maximum relative error between the contact force estimated by using the corrected relative indentation as the input signal and the measured contact force is less than 3%. The estimated contact force is in good agreement with the measured value, and the correlation coefficient is above 0.92. It shows that the experimental correction of the relative indentation has achieved good results, which verifies the accuracy of the correction method.

Analytical Investigations on the Contact Force Between Bristle Packs and Shaft Surface of Brush Seals

2012 ◽  
Author(s):  
Jun Li ◽  
Jiandao Yang ◽  
Liqun Shi ◽  
Rui Yang ◽  
Zhenping Feng
Keyword(s):  
Contact Force ◽  
Beam Theory ◽  
Force Model ◽  
Normal Contact ◽  
Normal Contact Force ◽  
Whirling Motion ◽  
Variation Characteristics ◽  
Rotor Surface ◽  
Brush Seals ◽  
Shaft Surface

The contact force between single bristle and shaft surface, as well as full bristle pack and rotor surface were analytically investigated. The contact force model between single bristle and shaft surface was established using cantilever beam theory. The eccentric whirling motion was taken into account in the present numerical model. The numerical method for the normal contact force and tangential friction force between the seal and shaft surface was derived. The effects of the eccentric whirling motion, bristle lay angle and bristle interference on the contact force of brush seals were conducted using the developed analytical model and method. The variation characteristics of the normal contact force and tangential frictional force torque between single bristle and rotor surface along the circumferential direction with different bristle lay angle, eccentric whirling motion and bristle interference was illustrated and analyzed. The numerical analysis results of the contact force between full bristle pack and shaft surface show that the contact force decreases at first and increases later with increasing the bristle lay angle at the fixed bristle interference and eccentric whirling motion. The contact force obtains the minimum when the bristle lay angle equals to 54° at the eccentric whirling motion 0.5mm and bristle pack interference 1.5mm.

Dynamics Analysis of Truss Deployment Mechanism With Imperfect Joint Considering Input Fluctuation

2020 ◽  
Author(s):  
Zhengfeng Bai ◽  
Jijun Zhao ◽  
Xin Shi
Keyword(s):  
Contact Force ◽  
Dynamic Performance ◽  
Mathematic Model ◽  
Friction Model ◽  
Dynamic Responses ◽  
Force Model ◽  
Normal Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamic Performance Analysis

Abstract Modern spacecraft usually has large deployment structure, which consisting of plenty of joints could produce undesirable dynamic responses when considering clearances in joints and driving input fluctuation. However, in the dynamic performance analysis of space deployment mechanism, the clearances and input fluctuation are always ignored. In this study, the dynamic responses of a flexible planar scissor-like truss deployment mechanism with imperfect joint considering clearance and input fluctuation are investigated using computational methodology. First, the mathematic model of clearance joint is established. The revolute clearance joint is considered as force constraint and the joint components of an imperfect joint with clearance are modeled as contact bodies. The normal contact force model of clearance joint is established using a continuous contact force model considering energy loss. The friction effect is considered using a modified Coulomb friction model. Then, the dynamics performances of the flexible planar scissor-like truss deployment mechanism with imperfect joint considering clearance and input fluctuation are presented and discussed. Different case studies for the scissor-like truss deployment mechanism with clearance are investigated considering driving input fluctuation. The simulation results show that the dynamic characteristics of the mechanism with clearance joint are changed more obviously when considering driving input fluctuation. Therefore, investigation implies that dynamics responses of the truss deployment mechanism are much worse when considering clearance joint and input fluctuation, which indicates that driving input fluctuation leads to more obvious degradation of the dynamic performance of the truss deployment mechanism with imperfect joint.

scholarly journals Research on Dynamic Characteristic of Rudder Transmission System with Multiple Clearance Joints

2020 ◽  
Vol 38 (5) ◽  
pp. 994-1000
Author(s):  
Qi Wan ◽  
Geng Liu ◽  
Chunyu Song ◽  
Shangjun Ma ◽  
Ruiting Tong
Keyword(s):  
Contact Force ◽  
Axial Length ◽  
Contact Process ◽  
Transmission System ◽  
Force Model ◽  
Heavy Load ◽  
Normal Contact ◽  
Clearance Joints ◽  
Contact Force Model ◽  
Structural Optimization And Control

In order to meet the characteristics including small clearance, heavy load and large contact area of joints existed in rudder transmission system, a new normal contact force model is established, which is suitable for the large-area contact process and considers the coefficient of nonlinear variable stiffness as well as the axial length of bearing. The applicability of this model is verified by simulations under some conditions with different clearance size, restitution coefficient, initial collision speed and bearing's axial length. Furthermore, through the user-defined subroutine interface in ADAMS software, this modified contact force model is compiled and linked into the dynamic model of the rudder transmission system. The simulation results show that the dynamic response of the system with multiple clearance joints is not a simple superposition of that with one single clearance, and the dynamic interaction between these joints intensifies the oscillation and nonlinear characteristics of the system. This study provides a theoretical reference for the structural optimization and control strategy design of aircraft with clearance joints.

Nonlinear Contact Parameter Estimation for Robotic Systems With Payload

2007 ◽  
Author(s):  
Xiuping Mu ◽  
Inna Sharf
Keyword(s):  
Parameter Estimation ◽  
Contact Force ◽  
Estimation Algorithm ◽  
Force Model ◽  
Contact Parameter ◽  
Normal Contact ◽  
Normal Contact Force ◽  
Nonlinear Contact ◽  
Six Dof ◽  
Contact Parameters

Simulating robotic operations where the robot interacts with its environment remains a challenging task because of the difficulties involved in contact modeling. At present, the basic methodologies for modeling contact are well established and have been integrated into many existing multibody dynamics formulations and software. One popular approach involves modeling the normal contact force as a continuous function of deformation, according to a particular constitutive relation. These models are usually simple in form and are easily integrated into any multibody framework because they provide an explicit relationship between the normal contact force and a geometric penetration variable, with the aid of appropriate contact parameters. One issue that remains ambiguous, however, is the choice of the contact parameters to be ‘fed’ into the force-deformation law. In this paper, the problem of contact parameter estimation is addressed in the context of a nonlinear contact force model proposed by Hunt and Crossley. An offline parameter estimation algorithm is developed which effectively transforms the nonlinear estimation problem into a linear one, it in turn solved using a multi-pass recursive technique. Results of application of the algorithm to simulated and experimental data are presented, the latter obtained with a six-DOF robotic manipulator and a variety of payload materials and geometries. Comparison of the proposed method to the nonlinear curve fitting algorithm from MATLAB demonstrates some advantages and limitations.

scholarly journals Dynamics of Multibody Systems With Spherical Clearance Joints

2005 ◽  
Author(s):  
P. Flores ◽  
J. Ambro´sio ◽  
J. C. P. Claro ◽  
H. M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Contact Forces ◽  
Force Model ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamics Of Multibody Systems ◽  
The Impact

This work deals with a methodology to assess the influence of the spherical clearance joints in spatial multibody systems. The methodology is based on the Cartesian coordinates, being the dynamics of the joint elements modeled as impacting bodies and controlled by contact forces. The impacts and contacts are described by a continuous contact force model that accounts for geometric and mechanical characteristics of the contacting surfaces. The contact force is evaluated as function of the elastic pseudo-penetration between the impacting bodies, coupled with a nonlinear viscous-elastic factor representing the energy dissipation during the impact process. A spatial four bar mechanism is used as an illustrative example and some numerical results are presented, being the efficiency of the developed methodology discussed in the process of their presentation. The results obtained show that the inclusion of clearance joints in the modelization of spatial multibody systems significantly influences the prediction of components’ position and drastically increases the peaks in acceleration and reaction moments at the joints. Moreover, the system’s response clearly tends to be nonperiodic when a clearance joint is included in the simulation.

Sign in / Sign up

Export Citation Format

Share Document