From a Geometrical Interpretation of Bramble-Hilbert Lemma to a Probability Distribution for Finite Element Accuracy

Author(s):  
Joel Chaskalovic ◽  
Franck Assous
2015 ◽  
Vol 21 (4) ◽  
pp. 503-513 ◽  
Author(s):  
Mohammad Javad Vahdatirad ◽  
Mehdi Bayat ◽  
Lars Vabbersgaard Andersen ◽  
Lars Bo Ibsen

The mechanical responses of an offshore monopile foundation mounted in over-consolidated clay are calculated by employing a stochastic approach where a nonlinear p–y curve is incorporated with a finite element scheme. The random field theory is applied to represent a spatial variation for undrained shear strength of clay. Normal and Sobol sampling are employed to provide the asymptotic sampling method to generate the probability distribution of the foundation stiffnesses. Monte Carlo simulation is used as a benchmark. Asymptotic sampling accompanied with Sobol quasi random sampling demonstrates an efficient method for estimating the probability distribution of stiffnesses for the offshore monopile foundation.


Author(s):  
Maher Nessim ◽  
Nader Yoosef-Ghodsi ◽  
Doug Honegger ◽  
Joe Zhou ◽  
Shanshan Wang

The application of reliability based design and assessment (RBDA) as a basis for seismic evaluations of natural gas pipelines is explored through analysis of a number of representative pipeline examples. To accomplish this, a simplified approach was developed to generate a representative probability distribution of permanent ground deformations due to soil liquefaction. An idealized pipeline alignment through a liquefiable layer under a river was defined, and a number of cases representing NPS12 and NPS36 pipelines in classes 1, 2 and 3 were analyzed using a finite element model. The probability of exceeding the strain limits for pipe body and girth weld were calculated and compared to the reliability targets. The results were used to identify diameter and class combinations that can meet the reliability targets, and to make preliminary conclusions regarding the viability of using RBDA for seismic evaluations.


2020 ◽  
Vol 28 (2) ◽  
pp. 63-74
Author(s):  
Joël Chaskalovic ◽  
Franck Assous

AbstractThe aim of this paper is to provide new perspectives on the relative finite elements accuracy. Starting from a geometrical interpretation of the error estimate which can be deduced from Bramble–Hilbert lemma, we derive a probability law that evaluates the relative accuracy, considered as a random variable, between two finite elements Pk and Pm, k < m. We extend this probability law to get a cumulated probabilistic law for two main applications. The first one concerns a family of meshes, the second one is dedicated to a sequence of simplexes constituting a given mesh. Both of these applications could be considered as a first step toward application for adaptive mesh refinement with probabilistic methods.


2021 ◽  
Vol 1210 (1) ◽  
pp. 012003
Author(s):  
Yubao Liu ◽  
Hanxiong Liu ◽  
Shouyi Sun

Abstract A three dimensional(3D) finite element model is established for a prestressed concrete girder bridge, list the limit state equation and variable probability distribution model, obtain the failure probability and reliability index of the limit state equation based on the Monte-Carlo method, investigate the reliability index’s sensitivity to random variables for limit state equations of bridge bearing capacity. The specific method of the research on the structure reliability index calculation is to select a suitable way that can fit the research’s object among the center point method, the checking-point method, the Monte-Carlo method, the importance sampling method, and so on. Authors use finite element software ANSYS to build model and perform 3D force analysis. According to the results, authors can determine the bridges’ failure modes under the state of 3D stress. Then, authors can list the possible limit state equations related to Stiffness, strength, function, durability, and some character else. After determining the bridge’s structural limit state equation and the probability distribution model of the variables, determine the distribution function of each impact factor and its characteristic parameters through the site survey data and other related data surveys. Then, use the Monte-Carlo method for the calculation of bridge reliability index, obtain the failure probability and reliability index of each limit state equation, analyze the sensitivity of each variable to the reliability index under the ultimate state of the bridge’s bearing capacity. At last, authors give construction quality control plans and suggestions according to the data above.


Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.


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