simFracture: Fatigue lifetime simulation

In simLife: Simulation of Fatigue Lifetimes

Description

Simulation of fatigue lifetime model

Usage

simFracture(stress, S, opt, param, last.defect = FALSE, CL = NULL)

Arguments

stress	applied stress level
S	non-overlapping geometry system
opt	control list for simulation of individual failure times
param	parameter list for generating individual failure times
last.defect	logical, last.defect=FALSE (default), return either all defect accumulations or only the last one
CL	optional, NULL (default), predefined clustered regions of objects

Details

We provide a wrapper function for simDefect to simulate the proposed fatigue lifetime model including the generation of individual failure times with additional information of the responsible accumulated defect projection area (simply called defect area) which leads to the failure of the system. This information is returned in the following list with elements: crack the responsible defect itself, T the individual failure times of objects aggregated as a cluster of objects, ferrit whether any secondary phase (here called ferrit) is involved for overall failure, interior whether the defect occurs in the interior or at the boundaries of the simulation box. The optional list argument CL defines clustered regions, see simCluster, of objects sticking together more close than others. This is useful in case one also wishes to model densely lieing agglomerations of objects (i.e. clusters of particles or fibers) as an obvious phenomenon of some specimen in mind. This list is made up of the following elements: id, the id of the region, center the center point of the corresponding region, r the radius (as the Euclidean distance from the center point) which within all objects belong to this region, interior whether any object within radius r hits the box boundaries of the simulation box.

Value

a list made up of the following objects if last.defect=FALSE (default):

• fracture return value of simDefect

• times return value of simTimes

• cl_info additional cluster information of responsible defect cluster

otherwise only cl_info is returned.

Author(s)

M. Baaske

Examples

## Not run: 

## Simulate a defect accumulation of a particle system

## primary particles (as prolate spheroids)
## and secondary phase (as spheres)
data(AL2MC_20p_k10_F2p_S)

## which is clustered and densified according to CL 
## additional predefined clustered regions
data(AL2MC_20p_k10_F2p_CL)

## the box is stored together with the geometry system 
box <- attr(S,"box")

## distTol=0.25, so use 25% of accumulation distance
opt <- list("vickers"=107, "distTol"=0.25, "Tmax"=10^12,
		"inAreafactor"=1.56, "outAreafactor"=1.43, 
		"pointsConvHull"=10, "scale"=1e+06,"pl"=101)

## constants 'const' are set to the following internally
## and can partially be overwritten if needed
# const <- list("Em"=68.9,"Ef"=400,"nc"=28.2,"nu"=0.33,
#		    "pf"=0.138,"nE"=NULL,"sigref"=276,"Vref"=5891)

par <- list("P"=c(0.01,5,0.5,50,-11,3),
		"F"=c(0,0,0,105,-12,1),"const"=NULL)

# stress amplitude applied	
stress <- 110
## generate individual (particles') failure times
CLT <- simTimes(S,par,vickers=opt$vickers,stress=stress,cores=1L)

## generated random failure times
T <- unlist(sapply(CLT,`[[`,"T"))
V <- unlist(sapply(CLT,`[[`,"V"))
U <- unlist(sapply(CLT,`[[`,"U"))

dev.new()
showDensity(list("Debonding"=log10(V),"Fracture"=log10(U),"Failure time"=log10(T)),xlim=c(-2,15))

# Area max
(inA <- areaCrit(opt$vickers, stress=stress, factor=opt$inAreafactor, scale=opt$scale))
(outA <- areaCrit(opt$vickers, stress=stress, factor=opt$outAreafactor, scale=opt$scale))

## run accumulation
RET <- simDefect(stress,S,CLT,opt)
length(RET)

#### alternatively, includes simulating times by 'simTimes'
# SIM <- simFracture(stress,S,opt,par,last.defect=FALSE,CL=CL)	
# SIM$cl_info

## some simple analysis of accumulation paths until failure,
## that is, while the critical area is exceeded
LR <- RET[[length(RET)]]
isInCluster <- any(unlist(lapply(CL,function(x,y)
					any(y$id %in% x$id) , y=LR)))
cat("Broken cluster: ", isInCluster,"\t Ferrit: ",
	any("F" %in% LR$label),"\t Acc.size",length(LR$id),"\n")
	
## select only clusters of size larger than 'msize'	
msize <- 1
id <- sapply(RET,function(x) ifelse(length(x$id)>msize,TRUE,FALSE))
cat("Number of defect projections in last cluster: ",length(RET[[length(RET)]]$id),"\n")

## draw all accumulation paths until failure
dev.new()
L <- plotDefectAcc(RET,last.path=FALSE)
## draw last accumulation path until failure
dev.new()
L <- plotDefectAcc(RET,last.path=TRUE)

## 3D visualization of final defect projection area
#library(rgl)
#library(unfoldr)
#qid <- LR$id
#open3d()
#spheroids3d(S[qid],box=box, col=c("#0000FF","#00FF00","#FF0000","#FF00FF"))
#
### drawing only last cluster leading to failure
#drawDefectProjections(S,list(LR))

## End(Not run)

simLife documentation built on May 2, 2019, 6:36 a.m.