flac3d5.0结构单元教程.ppt

单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,.,*,单击此处编辑母版标题样式,FLAC3D 5.0,培训日程安排,FLAC3D,V5.0,界面操作,FLAC3D,基本操作方法,vs,应用流程,；,FLAC3D,内置,Fish,语言的应用；,FLAC3D,结构单元,vs,接触单元；,FLAC3D,渗流模块,其他,.,StructuralElement,.,FLAC,3D,结构单元,结构单元的类型,结构单元的建模方法,结构单元的参数取值,结构单元实例分析,关于,link,.,FLAC3D,中包含六种形式的结构单元，可以分成两类：,线型结构单元,：,梁,单元,(beam),锚索单元cable),桩单元,(pile),壳,型,结构单元,：,壳单元,(shell),土工格栅,(geogrid),衬砌单元,(liner),FLAC3D,中的结构单元是岩土工程中实际结构的一种“抽象”，即采用简单的单元形式来模拟复杂的结构体。,结构单元由结构节点,(node),和结构构件,(SELs),构成。,结构单元中的节点,(node),可以与周围的实体网格,(zone),或其它结构节点建立连接,(link),，通过连接实现岩土体或结构与其它结构发生相互作用。,注意：结构节点并不是简单地与实体网格的节点,(gridpoint),建立联系，也不能建立,node,与,gridpoint,之间的,link,1,、结构单元的类型,.,梁,单元,sel beam id 1 beg 4 0-1 end 5 0-2 nseg 4,sel node id=1 0 0 0,sel node id=2 2 0 0,sel node id=3 4 0-1,sel node id=4 5 0-2,sel beamsel cid=1 id=1 node 1 2,;,sel beamsel cid=2 id=1 node 2 3,sel beamsel cid=3 id=1 node 3,4,桩,单元,sel pile id 1 beg 0 0 0 end 0 0 10 nseg 4,2,、结构单元的建模方法,两种建模方式各有各的优点，第二种方式适合建立复杂曲线结构单元（,但是要注意它不会自动建立,link,！若不手动,link,就无任何作用,）,.,锚索,单元,sel,cable,id 1 beg 4 0-1 end 5 0-2 nseg,4,2,、结构单元的建模方法,.,建立梁单元，并显示单元坐标系！,2,、结构单元的建模方法,线型结构单元,起始点坐标并给定分段数目的方法；,.,ID,号相同，共用,Node,，,ID,不同，各个,ID,对应的结构单元有各自独立的,node,。除非设置联系，否则即使节点位于同一位置也不会传递力。,结构单元的显示！,GUI,操作和命令操作（,manual,）调整好显示效果后可以将显示的命令文件另存出来，以备下次使用。（最适用于几何模型相同，参数不同的，不同工况分析的比较）,2,、结构单元的建模方法,线型结构单元,.,先建立节点再联接成单元的方法；,2,、结构单元的建模方法,线型结构单元,.,壳单元,2,、结构单元的建模方法,壳型结构单元,.,def set_vals,global ptA=25.0*sin(40.0*degrad);,global ptB=25.0*cos(40.0*degrad),end,set_vals,generate zone cylinder p0=(0.0,0.0,0.0)&,p1=(ptA,0.0,ptB)&,p2=(0.0,25.0,0.0)&,p3=(0.0,0.0,25.0)&,p4=(ptA,25.0,ptB)&,p5=(0.0,25.0,25.0)&,size=(1,2,2),sel shell id=5 range cylinder end1=(0.0,0.0,0.0)&,end2=(0.0,25.0,0.0)radius=24.5 not,plot,add,zg,plot ad sel geom,delete zones;delete all zones,sel node init zpos add-25.0,2,、结构单元的建模方法,壳型结构单元,.,通过附着在实体网格表面来生成,shell,单元。,The shells can then be repositioned if ecessary by using the SEL node init command,2,、结构单元的建模方法,壳型结构单元,.,FLAC3D,是岩土工程的专业软件，因此一般很少用来做专门的结构分析。在涉及到结构单元的问题中，往往都要考虑结构与周围的实体单元的相互作用。在结构单元的建模时要特别注意一个基本原则：,一个,zone,至多包含一个,structure node,!,因此在建立线型结构单元时，要特别注意,nseg,变量的大小。,nseg,太小则会导致计算不精确，而太大就会违反结构单元建模的基本原则。,2,、结构单元的建模方法,注意事项,.,梁单元,emod,弹性模量，,E,nu,泊松比，,xcarea,横截面积，,A,xciy,梁结构,y,轴惯性矩,I,y,xciz,梁结构,z,轴惯性矩，,I,x,xcij,极惯性矩，,J,density,密度，,pmoment,塑性矩，,M,p,thexp,热膨胀系数，,t,ydirection,矢量,Y,锚索,单元,emod,弹性模量，,E,xcarea,横截面积，,A,gr_coh,单位长度上水泥浆粘结力,c,g,gr_fric,水泥浆的摩擦角,g,gr_k,单位长度上,水泥浆刚度,k,g,gr_per,水泥浆外圈周长,P,g,slide,大变形滑动标志,slide_tol,大变形滑动容差,ycomp,抗压强度,(,力,),density,密度,thexp,热膨胀系数,3,、结构单元的参数取值,.,3,、结构单元的参数取值,某些结构单元参数的取值要视具体情况而定，根据经验且必要时调整参数通过试算来确定。,.,4,、结构单元实例分析,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,4.2,、简支梁（,shell,单元）承受两个相等集中载荷,.,Simple Beam Two Equal Concentrated Loads,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,.,A simply supported beam is loaded by two equal concentrated loads,symmetrically placed as shown in Figure 1.9.The shear and moment diagrams for this configuration are also shown in the figure.The shear force magnitude,V,is equal to the applied concentrated load,P.The maximum moment,Mmax,occurs between the two loads and is equal to Pa.The maximum deflection of the beam,max,occurs at the center and is given by AISC(1980,p.2-116)as,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,.,载荷,(N),载荷距支座的距离,(m),铰支座之间的距离,(m),弹性模量,(Pa),惯性矩,(m4),惯性矩,(m5),最大挠度,(m),P,a,L,E,Iy,Iz,max,10000,3,9,2.00E+11,2.00E-04,2.00E-04,0.006468750,根据理论公式计算得到：,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,.,new,title Simple Beam-Two Equal Concentrated Loads Symmetrically Placed,;=,;Create the grid,insure that nodes will exist at third points.,sel beam id=1 begin=(0,0,0)end=(3,0,0)nseg=3,sel beam id=1 begin=(3,0,0)end=(6,0,0)nseg=4,sel beam id=1 begin=(6,0,0)end=(9,0,0)nseg=3,;Assign beam properties,sel beam id=1 prop emod=2e11 nu=0.30&,xcarea=6e-3 xcj=0.0 xciy=200e-6 xciz=200e-6,;=,;Specify model boundary conditions(including applied loads),sel node fix z xr yr;restrict all non-beam modes,sel node fix y range id=1;,sel node fix y range id=9;rollers at beam ends,sel node apply force=(0.0,-1e4,0.0)range id=2;apply point loads,sel node apply force=(0.0,-1e4,0.0)range id=5;,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,.,;=,;Setup histories for monitoring behavior.,history add id=10 sel node ydisp id=7,history add id=30 sel beamsel moment mz end2 cid=1;moment,right of SEL-1,history add id=31 sel beamsel moment mz end1 cid=2;moment,left of SEL-2,;=,;Bring the problem to equilibrium,solve ratio=1e-7,save equal-concent-loads,;=,;Print out beam responses.,list sel beam force,list sel beam moment,list sel node disp range id=7,return,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,如何设置结构单元的跟踪变量！,.,Beam_concent_loads_Example1.3,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,.,挠度计算,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,.,剪力、弯矩计算,.,剪力、弯矩计算,这是节点力！,.,.,梁单元局部坐标系：,x,轴从节点,1,到节点,2,，,y,轴在横截面中,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,.,弯矩矢量的指向，右手法则！,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,.,List sel beam,nodal,forces:,components are displayed in terms of the beam local coordinate systems.These are the forces exerted by the nodes on the beamSEL.,小结：梁单元的常用命令,4.1,、简支梁（,beam,单元）承受两个相等集中载荷,history sel,beamsel,cid,怎么找？（坐标,or,鼠标,information,？）,.,sel,Sel node,命令 针对所有的结构单元,.,Sel,node,fix,keyword .,.,new,title Simple Beam(modeled using shellSELs),gen zone brick size 12,3,1&,p0 0,0,1.0 p1 9,0,1.0 p2 0 0 0 p3 0 1 1.0 ;,shell,宽度为单位,1,（,z,方向上）,sel shell id=1 crossdiag elemtype=dkt range y-0.1 0.1,sel shell id=1 prop iso=(2e11,0.0)thick=0.133887,delete zone,sel node fix x y xr yr range x=(-0.1,0.1);support at left end hinge,铰支座,sel node fix y xr yr range x=(8.9,9.1);support at right end roller,辊轴支座,sel node fix z xr yr;restrict non-beam deformation modes,sel node apply force=(0,-1667,0)range union id=71 id=12;out nds,left,sel node apply force=(0,-3333,0)range union id=46 id=13;in nds,left,sel node apply force=(0,-1667,0)range union id=79 id=24;out nds,rt.,sel node apply force=(0,-3333,0)range union id=54 id=25;in nds,rt.,将均布载荷转换为等效节点力,4.2,、简支梁（,shell,单元）承受两个相等集中载荷,.,history add id=1 unbal,history add id=10 sel node ydisp id=19;displ at center,;moment,left third,history add id=20 sel recover sres Mx surfX 1,0,0 cid=59,;shear,left third,history add id=30 sel recover sres Qx surfX 1,0,0 cid=59,solve ratio=1e-7,list sel node disp range id=19,save shell0,return,4.2,、简支梁（,shell,单元）承受两个相等集中载荷,.,4.2,、简支梁（,shell,单元）承受两个相等集中载荷,.,sel shell id=1 elemtype=cst range y-0.1 0.1;no-crossdiag,sel shell id=1 crossdiag elemtype=dkt range y-0.1 0.1,Crossdiag vs no-crossdiag,4.2,、简支梁（,shell,单元）承受两个相等集中载荷,.,局部坐标系！看弯矩到底应该看哪一个？,.,4.2,、简支梁（,shell,单元）承受两个相等集中载荷,.,4.2,、简支梁（,shell,单元）承受两个相等集中载荷,.,.,4.2,、简支梁（,shell,单元）承受两个相等集中载荷,.,surfX,Xx Xy Xz,The surfx vector(Xx,Xy,Xz)enables a surface coordinate system to be generated for all nodes used by the shell-type SELs in the optional range.The surface coordinate system,xyz,has the following properties:,(1)z is normal to the surface;(2)x is the projection of the given surfx vector onto the surface;,and(3)y is orthogonal to x and z.The z-direction is found at each node by taking the average normal direction of all shell-type SELs in the range.If the surfx vector is aligned at z at any node,then processing stops and an error message is displayed.To proceed,designate a different surfx vector,or restrict the range of shell-type SELs considered.,The surface coordinate system can be queried with the command,LIST,sel recover surface and the FISH function,nd_ssys,.It can also be set for an individual node with the FISH function,nd_ssysx,.It can be visualized with the sel geometry plot item by setting the systemtype switchword.,The validity of the surface system at a particular node can be queried with the FISH function,nd_svalid,.The surface system at a node automatically becomes invalid under the following conditions:(1)large-strain update;or(2)creation or deletion of a shell-type SEL that uses the node.Validity must be reestablished with the SEL recover surface command.,Sel,Rec,over keyword ,.,5,、关于,link,两种：,Node-Zone,Node-Node,.,创建一个新的,link,，,link,的源节点为,sid,，而联接目标为,node,或,zone,。,Id,为新,link,的,ID,号。,Sid,是已经存在的节点（作为源节点）的,ID,号，可选关键字,target,用于确定目标对象（,node,或,zone,）。默认的目标对象为,zone,。,对于,zone,目标对象，如果,tid,没有定义，将会使用与源节点距离在,delta,范围内的非空,zone,；否则，如果,tid,定义了，如果该,tid,所指示的单元为非空,zone,，且该,zone,的边界距离在,delta,之内，就会建立link,。,对于,node,目标对象，,tid,就必须定义了，且两个节点必须彼此很靠近。由,delta,确定。如果不能确定源和目标对象，就会报错，且该命令不会对模型产生任何作用。新,link,的,attachment,条件设置为,6,个自由度均为“,rigid,”。,Side1,，,side2,关键字对于确定嵌入式,liner,的哪个面上产生,link,。,sel,可选参数与必选参数！,.,5,、关于,link,以预应力锚杆的托盘模拟为例,sel cable id=1 beg 0,0,0 end 0,29,0 nseg 10,sel cable id=1 beg 0,29,0 end 0,35,0 nseg 6,sel cable id=1 prop emod 2e10 ytension 310e3 xcarea 0.0004906&,gr_coh 1 gr_k 1 gr_per 0.0785 range cid 1,10,sel cable id=1 prop emod 2e10 ytension 310e3 xcarea 0.0004906&,gr_coh 10e5 gr_k 2e7 range cid 11,17,sel delete link range,id 1,；这里删除的是谁的,id,？,Sel link id=100 1 target zone,sel link attach xdir=rigid ydir=rigid zdir=rigid xrdir=rigid yrdir=rigid zrdir=rigid range id 100,sel cable id=1 pretension 60e3 range cid 1,10,.,FLAC,3D,数值模拟计算实例,Beam,单元基坑开挖,支护,以前述,extrude,的模型为例，进行隧道和基坑开挖支护,.,bulk(Pa),shear(Pa),fric(),coh(Pa),tens(Pa),1e8,0.3e8,35,1e3,1e3,开挖区域,材料力学参数,计算模型,几何边界,Beam,单元基坑开挖支护,FLAC,3D,数值模拟计算实例,.,基坑垮塌过程,Beam,单元基坑开挖支护,FLAC,3D,数值模拟计算实例,.,基坑垮塌过程,Beam,单元基坑开挖支护,FLAC,3D,数值模拟计算实例,.,基坑垮塌过程,Beam,单元基坑开挖支护,FLAC,3D,数值模拟计算实例,.,基坑垮塌过程,Beam,单元基坑开挖支护,FLAC,3D,数值模拟计算实例,.,Beam,单元基坑开挖支护,基坑垮塌过程,FLAC,3D,数值模拟计算实例,.,Beam,单元基坑开挖支护,基坑垮塌过程,FLAC,3D,数值模拟计算实例,.,Beam,单元基坑开挖支护,基坑垮塌过程,FLAC,3D,数值模拟计算实例,.Beam,单元基坑开挖支护,基坑垮塌过程,FLAC,3D,数值模拟计算实例,.,Beam,单元基坑开挖支护,基坑垮塌过程,FLAC,3D,数值模拟计算实例,.,Beam,单元基坑开挖支护,FLAC,3D,数值模拟计算实例,.,Beam,单元基坑开挖支护,最大不平衡力,FLAC,3D,数值模拟计算实例,.,Beam,单元基坑开挖支护,最大不平衡力,FLAC,3D,数值模拟计算实例,.,Interface,.,Interface-,概述,岩土工程中涉及到很多的接触问题，比如挡土墙与墙后填土之间的接触、桩与土接触、土石坝中混凝土防渗墙与土体之间的接触等。,FLAC/FLAC3D,提供了接触面单元，可以分析一定受力条件下两个接触的表面上产生错动滑移、分开与闭合。,概述,FLAC,和,FLAC3D,中的接触面单元可以用来模拟,岩体中的节理、断层；,地基与土体之间的接触；,矿仓与仓储物的接触面；,相互碰撞物体之间的接触面；,空间中的障碍边界（即固定的不变形的边界）条件。,FLAC3D,中建立接触面单元应遵循以下原则：,小的表面与大的表面相连时，接触面应建立在小的表面上；,如果两相邻的网格有不同的密度，接触面应建立在密度大的区域上；,接触面单元尺寸通常应该等于或小于相连的目标面的尺寸；,使用,Attach,命令连接的两个表面不应再建立接触面。,.,Interface-,概述,FLAC,和,FLAC3D,中的接触面采用的是无厚度接触面单元，接触面本构模型采用的是库仑剪切模型,。,FLAC3D,中接触面的基本理论,FLAC3D,中接触面单元由一系列三节点的三角形单元构成，接触面单元将三角形面积分配到各个节点中，每个接触面节点都有一个相关的表示面积。每个四边形区域面用两个三角形接触面单元来定义，然后在每个接触面单元顶点上自动生成节点，当另外一个网格面与接触面单元相连时，接触面节点就会产生。,FLAC3D,中接触面是单面的，认识这一点很重要，这点与二维,FLAC,中所定义的双面接触面不同。可以把接触面看作“收缩带”，可以在指定面上拉伸，从而导致接触面和与之可能相连的其它任何面的相互刺入变得敏感。接触面单元可以通过接触面结点和实体单元表面（称为目标面）之间来建立联系。接触面法向方向所受到的力由目标面方位所决定。在每个时间步计算中，首先得到接触面节点和目标面之间的绝对法向刺入量和相对剪切速度，再利用接触面本构模型来计算法向力和切向力的大小。,.,Interface-,概述,接触面单元、接触面节点以及节点表示面积的示意图。,.,为何要分离网格后再“移来移去”,.,.,1,、手册中给出的接触面建立方法,So-called,“移来移去法”,gen zone radcyl p0(0,0,0)p1(8,0,0)p2(0,0,-5)p3(0,8,0)&,p4(8,0,-5)p5(0,8,-5)p6(8,8,0)p7(8,8,-5)&,p8(.3,0,0)p9(0,.3,0)p10(.3,0,-5)p11(0,.3,-5)&,size 3 10 6 15 ratio 1 1 1 1.15,gen zone radcyl p0(0,0,-5)p1(8,0,-5)p2(0,0,-8)p3(0,8,-5)&,p4(8,0,-8)p5(0,8,-8)p6(8,8,-5)p7(8,8,-8)&,p8(.3,0,-5)p9(0,.3,-5)p10(.3,0,-8)p11(0,.3,-8)&,size 3 6 6 15 ratio 1 1 1 1.15 fill,gen zone reflect dd 270 dip 90,group zone clay;group clay(old command,）,.,1,、手册中给出的接触面建立方法,So-called,“移来移去法”,interface 1 face range cylinder end1(0,0,0)end2(0,0,-5.1)radius.31&,cylinder end1(0,0,0)end2(0,0,-5.1)radius.29 not,interface 2 face range cylinder end1(0,0,-4.9)end2(0,0,-5.1)radius.31,gen zone cylinder p0(00,6)p1(.3,0,6)p2(0,0,1)p3(0,.3,6)p4(.3,0,1)p5(0,.3,1)&,size 3 10 6,写简写的时候要注意新老版本的区别,gen zone cylinder p0(0,0,6.1)p1(.3,0,6.1)p2(0,0,6)p3(0,.3,6.1)&,p4(.3,0,6)p5(0,.3,6)&,size 3 1 6,gen zone reflect dd 270 dip 90 range z 1 6.1,group zone pile range z 1 6.1,pause,ini zposition add-6.0 range group pile;ini z add-6.0 range group pile(old command,）,.,1,、手册中给出的接触面建立方法,So-called,“移来移去法”,.,.,.,.,“移来移去”法,;Create Base,gen zone brick size 3 3 3&,p0(0,0,0)p1(3,0,0)p2(0,3,0)p3(0,0,1.5)&,p4(3,3,0)p5(0,3,1.5)p6(3,0,4.5)p7(3,3,4.5),group zone Base,;Create Top-1 unit high for initial spacing,gen zone brick size 3 3 3&,p0(0,0,2.5)p1(3,0,5.5)p2(0,3,2.5)p3(0,0,7)&,p4(3,3,5.5)p5(0,3,7)p6(3,0,7)p7(3,3,7),group zone Top range group Base not,;,;Create interface elements on the top surface of the base,interface 1 face range plane norm(-1,0,1)origin(1.5,1.5,3)dist 0.1,;Lower top to complete geometry,ini zpos add1.0 range group Top,.,2,、接触面建立方法,So-called,“倒来倒去法”,我们最终的目的就是在中心小块体与外围网格之间建立接触面。,分开建立网格,建立,inner,网格及其表面的,Interface,导,入外围,mesh,赋予材料属性，测试接触面是否发生了作用。,.,小练习：,三种建立接触面的方法计算结果是否相同（只要接触面有响应，肯定是相同的！）,如果将接触面建立在外部网格的内表面，然后移入小块体，结果是否相同呢？,不,加接触面跟加了接触面，模型的响应（位移、应力）有何区别？,Nrange,Example-7.1 union nrange,.,3,、切割模型的方法,实际上是分离连续网格（原来网格连续，通过共用节点（,GridPoint,）传递力，分离后通过接触面来传递。,gen zone brick size 3 3 3,group zone inner range x 1 2 y 1 2 z 2 3,group zone out range group inner not,generate separate face group aa range group inner group out,;very different from old version,interface 1 wrap first group inner;second group out,;interface 1 permeability on,interface 1 maxedge 0.5,.,Wr,ap,first,keyword.,second,keyword.,Interface elements are created on all zone faces belonging to the range specified,after the keyword first,.The tokens following first are a range descriptor as though normally used following,a range keyword,.Optionally,a second range may be given following the second keyword.,Interface elements are created along the zone boundary between the first and second ranges.,If no second range is given,the default second range is the entire model,indicating that the entire boundary of first range will be used,.Note that for an interface element to be created,an exact match must exist between gridpoints in space on either side of the boundary,although the faces themselves do not have to match exactly.To separate one group from another,see the,GENERATE,separate command.,For example,the following command would find the twinned faces between group rock and group soil,and put interface elements on the rock faces.Only faces with centroids within the range x 50.0 75.0 would be considered.,interface 1 wrap first group rock second group soil range x 50.0 75.0,接触面建立在第,1,个类组上面，若不指定第,2,个类组，就默认第,2,个类组为整个模型，边界面为整个第,1,个类组的表面。,.,Generate,Separate Zones,se,parate,face,keyword,separates(unmerges)the internal faces specified by the range.The gridpoints of the face are duplicated,and a new surface face is created.New faces and gridpoints get copies of all group and extra variable assignments belonging to the original face and gridpoint.,Note that faces may be restricted by giving two group range elements,therefore indicating that the face must be on the surface of the first and the second group.For instance,if Fred and George are group names assigned to zones,then,range group Fred group George,;,生成的应该是一个共享面,will select faces that are connected to both Fred and George.Also note that faces can be selected by group directly.,（此外，,face,也可以通过,group,直接选中）,The following keywords can be used to affect the behavior,产生由,range,定义的内部,face,。面上的节点复制，并创建新的表面。,.,The following keywords can be used to affect the behavior.,Cl,earattach By default,an error occurs if any gridpoint that has an attach condition associated with it is found among those to be separated.However,if the clearattach keyword is supplied,then the separation of gridpoints will occur regardless.In addition,FLAC3D will remove any attach condi