thermal convection load giving a 'misleading' error

Hello Team,

I was performing 1-d thermal analogy based diffusion analysis, using link33 and surf151 elements. I ran identical inputs both in 17.2 and 201. It worked fine in 17.2, but gave an error(below) in 201. I didn't check for other versions like 180 or 190.

 *** ERROR ***              CP =    0.742  TIME= 14:35:20

 Element 4 has a convection surface referencing a nonexistent HF     

 material property for material number 0.


--> Firstly, the above error is confusing and not clear what it meant.

--> Secondly, this error trap comes when the convection load was negative. But I don't think it's an issue, as it ran without any errors in 17.2

--> This error also occurs if I replace the link and surface effect elements and instead use traditional solid70 and apply convection load directly on the base element.


In short, it appears that sign of convection load is causing this issue. Could you please take a look into this issue and let me know the possible workaround for the newer versions to work.


Below is the input I used to reproduce the error.

FINISH  

/CLEAR,NOSTART

/filname,therm_1d 

/PREP7

LENGTH=2e-03         

HEIGHT=LENGTH     

THICK=HEIGHT

esize=HEIGHT

area=HEIGHT*THICK

/com, material:-1            

dccstinter_1=area*1  

mp,kxx,1,6e-04

mp,c,1,20

mp,dens,1,1


/com, material:-2

dccstinter_2=area*(-1)

mp,kxx,2,8e-04

mp,c,2,40

mp,dens,2,1


/com, geometry and meshing

ET,1,link33

ET,2,link33

et,3,surf151

keyo,3,8,4

et,4,surf151

keyo,4,8,4

r,1,area


k,1,-0.5*LENGTH,

k,2,0,0,0

k,3,0.5*LENGTH,

l,1,2

l,2,3

lglue,1,2

esize,esize

type,1

real,1

mat,1

lmesh,1

type,2

real,1

mat,2

lmesh,2


/com, surface effect element modeling

esel,s,type,,1

nsle

type,3

mat,3

real,3

esurf

allsel,all,all


esel,s,type,,2

nsle

type,4

mat,4

real,4

esurf

allsel,all,all


ini_temp=358     ! initial temperature

tunif,ini_temp

save

FINISH



/SOLU,

ANTYPE,TRANS

KBC,0


nsel,s,loc,x,0.5*LENGTH

nsel,a,loc,x,-0.5*LENGTH

d,all,temp,0

allsel,all,all 


/com, surface load for elm-1

esel,s,type,,3

sfe,all,1,conv,2,0.0  ! no heat generation

sfe,all,1,conv,,dccstinter_1   

allsel,all,all


/com, surface load for elm-2

esel,s,type,,4

sfe,all,1,conv,2,0.0  ! no heat generation

sfe,all,1,conv,,dccstinter_2   

allsel,all,all


OUTRES,ALL,ALL

TIME,1

NSUBS,1,1,1

solve

FINISH



/POST1

SET,LAST

prns,temp         ! NODAL CONCENTRATION PLOT AT TIME=60seconds

fini

Best Answer

Answers

  • Hello Team,

    Thank you for the response. I checked giving negative values to HF in MP command and its working now and clean.

Sign In or Register to comment.