Numerical simulation of installation of jacked piles in sand using material point method

2018 ◽  
Vol 55 (1) ◽  
pp. 131-146 ◽  
Author(s):  
R. Lorenzo ◽  
R.P. da Cunha ◽  
M.P. Cordão Neto ◽  
J.A. Nairn
Keyword(s):  
Constitutive Models ◽  
Material Point Method ◽  
Material Point ◽  
Point Method ◽  
Deep Foundations ◽  
Lateral Capacity ◽  
Pile Installation ◽  
Modified Cam Clay ◽  
Semi Empirical ◽  
Cam Clay

Pile installation has a great impact on the subsequent mechanical pile response. It is not, however, routinely incorporated in the numerical analyses of deep foundations in sand. Some of the difficulties associated with the simulation of the installation process are related to the fact that large deformations and distortions will eventually appear. The finite element method is not well suited to solve problems of this nature. Hence, an alternative procedure is tested herein, by using the material point method to simulate the installation of statically jacked or pushed-in type piles, which has successfully demonstrated its capacity to deal with this simulation. Two constitutive models were also tested, i.e., the modified Cam clay (MCC) and the subloading Cam clay (SubCam), allowing a clear perception of the great advantage to consider the soil with the SubCam model. The simulations have indeed reproduced some of the important features of the pile installation process, such as the radial stress acting around the pile’s shaft or the shaft’s lateral capacity, among other issues. The numerical results were additionally compared with known (semi-empirical) methods to derive the lateral capacity of the shaft, with a good and practical outcome.

scholarly journals An investigation of stress inaccuracies and proposed solution in the material point method

2019 ◽  
Vol 65 (2) ◽  
pp. 555-581 ◽  
Author(s):  
José Leόn González Acosta ◽  
Philip J. Vardon ◽  
Guido Remmerswaal ◽  
Michael A. Hicks
Keyword(s):  
Shape Function ◽  
Time Integration ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Material Point Method ◽  
Material Point ◽  
Point Method ◽  
Implicit Time ◽  
Integration Scheme ◽  
Time Integration Scheme

AbstractStress inaccuracies (oscillations) are one of the main problems in the material point method (MPM), especially when advanced constitutive models are used. The origins of such oscillations are a combination of poor force and stiffness integration, stress recovery inaccuracies, and cell crossing problems. These are caused mainly by the use of shape function gradients and the use of material points for integration in MPM. The most common techniques developed to reduce stress oscillations consider adapting the shape function gradients so that they are continuous at the nodes. These techniques improve MPM, but problems remain, particularly in two and three dimensional cases. In this paper, the stress inaccuracies are investigated in detail, with particular reference to an implicit time integration scheme. Three modifications to MPM are implemented, and together these are able to remove almost all of the observed oscillations.

A Material Point Method for Glacier Calving

2020 ◽  
Author(s):  
Johan Gaume ◽  
Ming Gao ◽  
Joshua Wolper ◽  
Martin P. Luethi ◽  
Andreas Vieli ◽  
...  
Keyword(s):  
Large Scale ◽  
Material Point Method ◽  
Material Point ◽  
Point Method ◽  
Computational Framework ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
Large Scale Geometry ◽  
Cam Clay ◽  
Good Agreement

<p>Glaciers calving ice into the ocean is predicted to significantly contribute to sea-level rise and will thus influence future climate. Although numerous factors that induce glacier calving have been identified and studied, it is still extremely challenging to develop a unified and continuum computational framework that simulates ice fracture and glacier calving taking into account all important ingredients such as the interaction between ice and water, including buoyancy and melting, on complex and large scale geometry. This prevents scientists to precisely predict calving rates at the outlet of glaciers. Here, we propose to address this issue through numerical simulations of glacier calving based on the Material Point Method and finite strain elastoplasticity. A non-associative Cam-Clay model was developed to simulate the ice while the water is modeled as a nearly in-compressible fluid. First, simplified 2D simulations were performed to analyse the size of calved icebergs which were in good agreement with analytical solutions. The model reproduces not only the vertical glacier fracture observed in real calving events but also iceberg formation and tsunami-wave generation. Finally, 3D simulations of glacier calving were performed, taking into account opened crevasses on the top of the glacier. Although at a preliminary stage, and lacking experimental validation, we show the promise of our approach for modeling glacier calving, and more generally glacier and sea-ice dynamics.</p>

scholarly journals An Enriched Constitutive Model for Fracture Propagation Analysis Using the Material Point Method

2014 ◽  
Vol 553 ◽  
pp. 731-736 ◽  
Author(s):  
Giang Dinh Nguyen
Keyword(s):  
Large Scale ◽  
Constitutive Models ◽  
Material Point Method ◽  
Fracture Propagation ◽  
Material Point ◽  
Point Method ◽  
Localized Deformation ◽  
New Approach ◽  
Smeared Crack Approach ◽  
Smeared Crack

We develop a novel constitutive modeling approach for the analysis of fracture propagation in quasi-brittle materials using the Material Point Method. The kinematics of constitutive models is enriched with an additional mode of localized deformation to take into account the strain discontinuity once cracking has occurred. The crack details therefore can be stored at material point level and there is no need to enrich the kinematics of finite elements to capture the localization caused by fracturing processes. This enhancement also removes the drawback of classical smeared crack approach in producing unphysical snapping back constitutive responses when the spatial resolution is not fine enough. All these facilitate the implementation of the new approach in the Material Point Method for analysis of large scale problems. Numerical examples of fracture propagation are used to demonstrate the effectiveness and potentials of the new approach.

The material point method for simulating dense snow avalanches over complex real terrain

2021 ◽  
Author(s):  
Xingyue Li ◽  
Betty Sovilla ◽  
Chenfanfu Jiang ◽  
Johan Gaume
Keyword(s):  
Material Point Method ◽  
Granular Flows ◽  
Material Point ◽  
Full Scale ◽  
Point Method ◽  
Constitutive Law ◽  
Snow Avalanches ◽  
Failure Patterns ◽  
Snow Properties ◽  
Modified Cam Clay

<p>Various dynamics models can reproduce the motion of avalanches from release to deposition. These models often simulate a conceptual avalanche, adopt depth-averaged approaches and do not resolve variations along flow depth direction, and thus have clear limitations. This study presents three-dimensional, full-scale modeling of dense snow avalanches performed using the complex real terrain of the Vallée de la Sionne avalanche test site in Switzerland. We use the material point method (MPM) and a large-strain elastoplastic constitutive law for snow based on a Modified Cam Clay model. In our simulations, various and transient avalanche flow regimes are simulated by setting distinct snow properties. Snow avalanches are investigated from release to deposition. Detailed simulation results include the initial failure patterns, the mechanical behavior during the flow, and the characteristics of the final avalanche deposits. More specifically in the release zone, we can observe brittle and ductile fractures depending on the defined snow properties. During the flow phase, we monitor the temporal and spatial variations of snow density in the avalanche. In particular, cohesionless granular flows, cohesive granular flows, and plug flows are associated with snow fracture, compaction, and expansion. Finally, we can observe the structure of the avalanche deposit surfaces which show distinguishable differences in terms of smoothness, granulation, and compacting shear planes. This new model can offer a quantitative analysis for studying avalanches in different regimes and provide a powerful tool for exploring the dynamics of full-scale avalanches on complex real terrain, with high physical detail.</p>

scholarly journals Numerical Simulation of Pile Installation in Saturated Sand Using Material Point Method

2017 ◽  
Vol 175 ◽  
pp. 72-79 ◽  
Author(s):  
Vahid Galavi ◽  
Lars Beuth ◽  
Bruno Zuada Coelho ◽  
Faraz S. Tehrani ◽  
Paul Hölscher ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Material Point Method ◽  
Material Point ◽  
Point Method ◽  
Saturated Sand ◽  
Pile Installation

scholarly journals A Hybrid Material Point Method for Frictional Contact with Diverse Materials

2019 ◽  
Vol 2 (2) ◽  
pp. 1-24 ◽  
Author(s):  
Xuchen Han ◽  
Theodore F. Gast ◽  
Qi Guo ◽  
Stephanie Wang ◽  
Chenfanfu Jiang ◽  
...  
Keyword(s):  
Hybrid Material ◽  
Frictional Contact ◽  
Material Point Method ◽  
Material Point ◽  
Point Method

Three-dimensional face stability analysis of shallow tunnels using numerical limit analysis and material point method

2021 ◽  
Vol 112 ◽  
pp. 103904
Author(s):  
Fabricio Fernández ◽  
Jhonatan E.G. Rojas ◽  
Eurípedes A. Vargas ◽  
Raquel Q. Velloso ◽  
Daniel Dias
Keyword(s):  
Stability Analysis ◽  
Limit Analysis ◽  
Three Dimensional ◽  
Material Point Method ◽  
Material Point ◽  
Point Method ◽  
Face Stability ◽  
Shallow Tunnels ◽  
Dimensional Face
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