slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
L. Schueremans, D. Van Gemert luc.schueremans@bwk.kuleuven.ac.be, PowerPoint Presentation
Download Presentation
L. Schueremans, D. Van Gemert luc.schueremans@bwk.kuleuven.ac.be,

Loading in 2 Seconds...

play fullscreen
1 / 18

L. Schueremans, D. Van Gemert luc.schueremans@bwk.kuleuven.ac.be, - PowerPoint PPT Presentation


  • 155 Views
  • Uploaded on

Using Monte Carlo and Directional Sampling combined with an Adaptive Response Surface for system reliability evaluation. L. Schueremans, D. Van Gemert luc.schueremans@bwk.kuleuven.ac.be, dionys.VanGemert@bwk.kuleuven.ac.be Department of Civil Engineering KULeuven, Belgium Praha

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'L. Schueremans, D. Van Gemert luc.schueremans@bwk.kuleuven.ac.be,' - kermit-baxter


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Using Monte Carlo and Directional Sampling combined with an Adaptive Response Surface for system reliability evaluation

L. Schueremans, D. Van Gemert

luc.schueremans@bwk.kuleuven.ac.be,

dionys.VanGemert@bwk.kuleuven.ac.be

Department of Civil Engineering

KULeuven, Belgium

Praha

Euro-Sibram, June 24 tot 26, 2002, Czech Republic

introduction
Introduction

Framework:

  • Ph. D. “Probabilistic evaluation of structural unreinforced masonry”,
  • Ongoing Research: “Use of Splines and Neural Networks in structural reliability - new issues in the applicability of probabilistic techniques for construction technology”.

Target:

  • obtain an accurate value for the global pf, accounting for the exact PDF of the random variables;
  • minimize the number of LSFE, which is of increased importance for complex structures;
  • remain workable for a large number of random variables (n). In practice, the number of LSFE should remain proportional with the number of random variables (n).
introduction1
Introduction

Level II and Level III methods:

introduction reliability methods
Introduction - reliability methods

#LSFE~9n

#LSFE~3/pf

VI

#LSFE~cte.n

methods for system reliability using an adaptive response surface
Methods for System Reliability using an Adaptive Response Surface

Real structure:high degree of mechanical complexity, numerical algorithms, non-linear FEM

Response Surface:low order polynomial, Splines, Neural Network,...

Reliability analysis

Optimal scheme: DARS or MCARS+VI

DARS:Matlab 6.1[Schueremans, 2001], Diana 7.1[Waarts,2000]

MCARS+VI:Matlab 6.1[Schueremans, 2001]

slide11

MCARS+VIMonte Carlo Adaptive Response surface Sampling+Variance Increase

g

LSF

RS

ladd

Dg,add

Dg,add

gRS,i

u

lRS

eg,i

gLSF,i

li

Step 3:

Monte Carlo Variance Increase on the Response Surface (vi).

Sampling function: h=n-0.4

IF|gRS(v i)|<|g,add|

calculate gLSF(vi)

update RS

update g,add

Else

.

dars and mcars vi
DARS and MCARS+VI

The number of direct LSFE remains proportional to the number of random variables (n),

There is no preference for a certain failure mode. All contributing failure modes are accounted for, resulting in a safety value that includes the system behavior, thus on level III.

safety of masonry arch1
Safety of masonry Arch

To evaluate the stability of the arch, the thrust line method is used (Heyman, 1982), which is a Limit Analysis. Following assumptions are made:

  • blocs are infinitely resistant,
  • joints resist infinitely to compression
  • joints do not resist to traction
  • joints resist infinitely to shear

An external program Calipous is used for the Limit State Function Evaluations [Smars, 2000]

safety of masonry arch2
Safety of masonry Arch

Failure modes - limit states - limit analysis based on thrust lines

safety of masonry arch4
Safety of masonry Arch

Figure: DARS-outcome - reliability vernus number of samples N

conclusions
Conclusions
  • Focus was on the use of combined reliability methods to obtain an accurate estimate of the global failre probability of a complete structure, within an minimum number of LSFE.
  • A level III method is presented and illustrated: (DARS/MCARS+VI
  • Ongoing research: Splines and Neural Network instead of low order polynomial for Adaptive Response Surface (ARS).
  • Acknowlegment: IWT-VL (Institute for the encouragement of Innovation by Science and Technology in Flanders).