A discrete element model and its experimental validation for the prediction of draft forces in cohesive soil

Obermayr, Martin; Vrettos, Christos; Eberhard, Peter; Däuwel, Thomas

doi:10.1016/j.jterra.2014.04.003

Cited by 50 publications

(23 citation statements)

References 13 publications

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“…As a result, these models become prohibitive in terms of computational time even for a small specimen of a cohesive solid (powder particles are 200 μm or smaller in size) and certainly impractical for modeling of any real industrial problems intended here. An alternative approach is to use larger particles in combination with DEM contact models that are able to capture the macroscopic cohesive behavior of the material [9][10][11][12]. Most of these contact models combine an elastic spring model with bonding between the particles so that contacts can resist tension forces.…”

Section: Introductionmentioning

confidence: 99%

DEM modeling of cone penetration and unconfined compression in cohesive solids

Janda

Ooi

2016

Powder Technology

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Section: Introductionmentioning

confidence: 99%

DEM modeling of cone penetration and unconfined compression in cohesive solids

Janda

Ooi

2016

Powder Technology

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“…The soil tool interaction force F L is a highly nonlinear component, which acts on the end effector. Several researches are dedicated to the computation of soil-tool interaction forces [62][63][64][65]. The influence of the soil-tool interactions on the state variables of the manipulator would also affect the friction torque generated at the revolute joints.…”

Section: History Of Dynamic Modellingmentioning

confidence: 99%

A review of friction models in interacting joints for durability design

2017

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This paper presents a comprehensive review of friction modelling to provide an understanding of design for durability within interacting systems. Friction is a complex phenomenon and occurs at the interface of two components in relative motion. Over the last several decades, the effects of friction and its modelling techniques have been of significant interests in terms of industrial applications. There is however a need to develop a unified mathematical model for friction to inform design for durability within the context of varying operational conditions. Classical dynamic mechanisms model for the design of control systems has not incorporated friction phenomena due to non-linearity behaviour. Therefore, the tribological performance concurrently with the joint dynamics of a manipulator joint applied in hazardous environments needs to be fully analysed. Previously the dynamics and impact models used in mechanical joints with clearance have also been examined. The inclusion of reliability and durability during the design phase is very important for manipulators which are deployed in harsh environmental and operational conditions. The revolute joint is susceptible to failures such as in heavy manipulators these revolute joints can be represented by lubricated conformal sliding surfaces. The presence of pollutants such as debris and corrosive constituents has the potential to alter the contacting surfaces, would in turn affect the performance of revolute joints, and puts both reliability and durability of the systems at greater risks of failure. Key literature is identified and a review on the latest developments of the science of friction modelling is presented here. This review is based on a large volume of knowledge. Gaps in the relevant field have been identified to capitalise on for future developments. Therefore, this review will bring significant benefits to researchers, academics and industry professionals.

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“…1 A convex cone is a subset K ⊂ X of a vector space, such that for any x, y ∈ K and α, β ≥ 0 it holds αx + β y ∈ K. 2 We are referring to a version of the theorem, that follows almost directly from [7, Theorem 4.6(i)], applied to absolutely continuous trajectories. 3 Many choices of constraint qualifications exist.…”

Section: Equations Of Motionmentioning

confidence: 99%

“…Rigid bodies are allowed to slightly overlap and a reaction force proportional to the overlap pushes them apart. The DEM has shown its potential to predict draft forces from the soil-tool interaction and it has been validated against experimental data [2]. Yet, due to the formulation using stiff contact forces, DEM relies on the use of very small time steps to maintain stability.…”

Section: Introductionmentioning

confidence: 99%

A conical interior point method for nonsmooth rigid body dynamics

Kleinert

Simeon

2015

AIP Conference Proceedings

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Reliable computer simulations of an excavation process can drastically reduce the cost for the product design of excavator buckets. Discrete Element Methods have proven valuable for the simulation of soil, yet they are only stable if the time step sizes are very small. A nonsmooth formulation of rigid body dynamics on the other hand is stable for much larger time step sizes. To predict draft forces in a simulation, nonsmooth rigid body dynamics rely on very effective numerical tools for high accuracy. In our contribution we provide a stringent derivation of the nonsmooth equations of motion for perfectly rigid bodies, and we propose a conical Interior Point Method as a solution technique for them

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A discrete element model and its experimental validation for the prediction of draft forces in cohesive soil

Cited by 50 publications

References 13 publications

DEM modeling of cone penetration and unconfined compression in cohesive solids

DEM modeling of cone penetration and unconfined compression in cohesive solids

A review of friction models in interacting joints for durability design

A conical interior point method for nonsmooth rigid body dynamics

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