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Mesh-Free Computational Shock and Fracture

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u<br />

#<br />

Stability of DPD (R<strong>and</strong>les ( R<strong>and</strong>les)<br />

System: Linear, forward Euler<br />

n 1<br />

2<br />

m<br />

( ) 2 n+<br />

1<br />

! •<br />

n+<br />

1 n $ t<br />

m = u m + "<br />

+ m<br />

#<br />

n+<br />

1<br />

m<br />

= # + " tC :<br />

n<br />

m<br />

( ) 1 n+<br />

! u<br />

Spatial derivatives: MLS<br />

n+<br />

1<br />

2 ( # •%<br />

) = % • $ w<br />

m<br />

!<br />

s"<br />

N ( m)<br />

n+<br />

1 ( # u)<br />

= u • $ w<br />

s !<br />

m"<br />

N(<br />

s)<br />

Assume: Plane harmonic wave solution<br />

u<br />

"<br />

n<br />

m<br />

n<br />

s<br />

= u !<br />

o<br />

= " !<br />

o<br />

n<br />

e<br />

ik•x<br />

n ik x<br />

e •<br />

On substitution:<br />

1<br />

% t 2 ( 1! # ) u o + $ # " oA<br />

m = 0<br />

o<br />

1<br />

2 ( ! " ) $ + # t " C : u B = 0<br />

1 o<br />

o s<br />

m<br />

s<br />

s<br />

A = ( $ ( e<br />

" % •x<br />

Eliminate to put in terms of u0<br />

)<br />

[ G f(<br />

) I]<br />

u 0 o = • ! "<br />

/ e<br />

" % •x<br />

)<br />

g =<br />

#<br />

"<br />

f<br />

( ! )<br />

f is function of time stepping method<br />

G is a function of local geometry<br />

<strong>and</strong> B = ( $ ( e<br />

" % •x<br />

)<br />

/ e<br />

" % •x<br />

)<br />

!

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