PFC6.0 案例-2-Simple Rigid Block Bonded-Block Modeling (BBM)简单刚性粘结块建模(BBM)（翻译自help文件）

; 清除模型状态并创建所有刚性块都存在的域
model new
model domain extent -10 10

;为UCS和直接拉伸测试创建高2.5倍宽的圆柱形几何集
geometry set 'specimen' 
[specRadius = 1.5]
[specHeight = 7.0]
geometry generate cylinder base 0 0 [-specHeight/2.0] radius [specRadius] ...
                  height [specHeight] axis 0 0 1 resolution 0.4

; 创建刚性块作为四面体。这个命令网格几何集，创建刚性块。
rblock construct from-geometry 'specimen' maximum-edge 0.4 

;缩放刚性块，使它们最初是重叠的。这是需要的接触位置是正确的，当粘接。
;当调用键合方法时，接触位置只是增量更新。
rblock scale relative 1.01

;腐蚀刚性块，引入圆角。 
;这允许剔除大量对模型响应没有贡献的边-边和顶点-顶点接触。 
;这有时可能会失败，所以最好使用skip-errors关键字
rblock erode relative skip-errors 0.05

;将顶部和模板组合在一起，这些模板是由刚性块组成的固定块。
rblock group 'top-platen' range position-z [specHeight/2.0 - 0.3] 10
rblock group 'bottom-platen' range position-z [0.3 - specHeight/2.0] -10

;设置阻尼和密度
rblock attribute density 2650 damp 0.7 

;粘结抗拉强度
[tensileStrength = 4.7e6]

;内聚力与抗拉强度之比
[cohesionFactor = 2.4]

;目标弹性模量放入键中
[emod = 7.25e10] 

;指定软粘结模型属性。
contact cmat default model softbond method deformability emod [emod] ...
                           kratio 2.0 ...
                           property sb_ten [tensileStrength] ...
                           sb_coh [cohesionFactor*tensileStrength] ...
                           sb_fa 30.0 fric 0.5 sb_mode 1
                      
; Create the contacts and bond them. Note that no softening is used in this 
; example so the softbond contacts act essentially as parallel bond contacts 
; except that there is only 1 set of stiffnesses and the shear stress is not 
; nulled if shear failure occurs. 
model clean all
contact method bond 

; Make the platen contacts have the null contact model. This is to reduce 
; computation and to ensure that they do not contribute to the stress 
; computation. The match keyword is used to specify that contacts fall within
; the range if both of the ends have the specified group. 
contact model null range group 'top-platen' match 2
contact model null range group 'bottom-platen' match 2

; Inhibit the contacts that are not bonded. This is VERY important for 
; efficient bonded ; block models. This means that the force-displacement law
; for edge-edge and vertex-vertex contacts is skipped along with updating the
; contact positions. You can compare the results and runtimes with and without
; the vertex-vertex and edge-edge contacts. If in small strain these contacts
; can actually be deleted with the contact delete command and contact 
; detection can be turned off. 
contact inhibit range contact gap 0 100

; Fix the velocity and spin of the top and bottom platens
rblock fix vel spin range group 'top-platen' 
rblock fix vel spin range group 'bottom-platen' 

; Make maps of the rigid blocks in the platens
[topMap = rblock.groupmap('top-platen')]
[botMap = rblock.groupmap('bottom-platen')]

; Define a FISH function to compute the stress and elastic modulus. 
; Histories of these quantities will be kept for display. 
fish define stress
    local stressTop = 0.0
    local stressBot = 0.0
    strain = 0.0
    loop foreach b topMap
        stressTop = stressTop + math.abs(rblock.force.contact(b,3))
        strain = 2.*math.abs(rblock.disp(b,3))
    endloop
    loop foreach b botMap
        stressBot = stressBot + math.abs(rblock.force.contact(b,3))
    endloop
    local st = (stressTop + stressBot)/(2.0 * math.pi*specRadius^2);
    strain = strain/specHeight
    if strain > 0
        modulus = st / strain
    endif
    stress = st
end
fish history @stress
fish history @strain
fish history @modulus

; Set up a FISH halt to end cycling when the stress is 80% of the maximum
[maxStress = 0.0]
[peakPercentage = 0.8]
fish define halt
    halt = 0
    maxStress = math.max(maxStress,stress)
    if stress < peakPercentage * maxStress
        halt = 1
    endif
end

; Register for fragment computation
fragment register rblock-rblock

; Save the specimen
model save 'specimen'