蠢小白，裂纹不是就拉伸和剪切裂纹吗，那单纯的crack是啥呢，而且为啥crack_shear，crack_tension的数量几乎是一样的呢？

看看裂纹代码

; fname: fracture.p3fis
;
; Simple environment to track fragmentation in a BPM.
; Track LinearPBond model "bond_change" events and turn them into fractures.
; Use Fragment logic and Ball Result logic to record fragemnt ids
;
;=============================================================================
fish define add_crack(entries)
local contact = entries(1)
local mode = entries(2)
local frac_pos = contact.pos(contact)
local norm = contact.normal(contact)
local dfn_label = 'crack'
local frac_size
local
bp
1 = contact.end1(contact)
local bp2 = contact.end2(contact)
local ret = math.min(ball.radius(bp1),ball.radius(bp2))
frac_size = ret
local arg = array.create(5)
arg(1) = 'disk'
arg(2) = frac_pos
arg(3) = frac_size
arg(4) = math.dip.from.normal(norm)/math.degrad
arg(5) = math.ddir.from.normal(norm)/math.degrad
if arg(5) < 0.0
arg(5) = 360.0+arg(5)
end_if
crack_num = crack_num + 1
if mode = 1 then
; failed in tension
dfn_label = dfn_label + '_tension'
else if mode = 2 then
; failed in shear
dfn_label = dfn_label + '_shear'
endif
global dfn = dfn.find(dfn_label)
if dfn = null then
dfn = dfn.create(dfn_label)
endif
local fnew = fracture.create(dfn,arg)
fracture.prop(fnew,'age') = mech.time.total
fracture.extra(fnew,1) = bp1
fracture.extra(fnew,2) = bp2
crack_accum += 1
if crack_accum > 50
if frag_time < mech.time.total
frag_time = mech.time.total
crack_accum = 0
command
fragment compute
endcommand
; go through and update the fracture positions
loop for (local i = 0, i < 2, i = i + 1)
local name = 'crack_tension'
if i = 1
name = 'crack_shear'
endif
dfn = dfn.find(name)
if dfn # null
loop foreach local frac dfn.fracturelist(dfn)
local ball1 = fracture.extra(frac,1)
local ball2 = fracture.extra(frac,2)
if ball1 # null
if ball2 # null
local len=fracture.diameter(frac)/2.0
local pos=(ball.pos(ball1)+ball.pos(ball2))/2.0
if comp.x(pos)-len > xmin
if comp.x(pos)+len < xmax
if comp.y(pos)-len > ymin
if comp.y(pos)+len < ymax
if comp.z(pos)-len > zmin
if comp.z(pos)+len < zmax
fracture.pos(frac)= pos
end_if
end_if
endif
endif
endif
endif
endif
endif
endloop
endif
endloop
endif
endif
end
fish define track_init
command
fracture delete
model results clear-map
fragment clear
fragment register ball-ball
endcommand
; activate fishcalls
command
fish callback remove @add_crack event bond_break
fish callback add @add_crack event bond_break
endcommand
; reset global variables
global crack_accum = 0
global crack_num = 0
global track_time0 = mech.time.total
global frag_time = mech.time.total
global xmin = domain.min.x()
global ymin = domain.min.y()
global xmax = domain.max.x()
global ymax = domain.max.y()
global zmin = domain.min.z()
global zmax = domain.max.z()
end
;=============================================================================
; eof: fracture.p3fis

你的代码看上去没啥问题

左侧显示的fracuture的数量是总数量，你在右边的dfn-plot中可以自己选择显示那些裂纹，就能看到哪些是剪切哪些是拉伸裂纹了