Abaqus_v6[1].7新功能介绍

O ver the years there have been a number of automotive tech-nologies promoted as next year’s new thing. But some-how, they never quite arrived.Surely, the Continuously Vari-able Transmission fits into that category. Since it was first put into tiny little Dutch-built DAF cars 40 years ago, the benefits of CVTs have been explained to countless classes of automo-tive technicians. But as a mainstream trans-mission, CVTs have been stuck in low gear.This is about to change in a big way. Ford will introduce a CVT transmission in three new vehi-cles this summer—the Five Hundred, the Mer-cury Montego and the Freestyle. And these will not be small vehicles. This transmission will be in high-volume, domestically produced vehicles with an engine capable of 250 ft.-lbs. of torque. While other makers have been in production with CVTs,this is a mass-market break-through for this technology.Ford is not alone in mov-ing CVTs into higher pow-ered cars. The only transmis-sion option of-fered by Nis-san in its V6-powered Mu-rano is a CVT.Honda contin-ues to make the Multitron-ic transmis-sion. The Au-di A4 has a CVT option,as does the Mini Cooper.In addition, both the Toyota Prius and Honda Insight are equipped with CVT transmissions.While mass-market CVTs strapped to higher output engines is a story in itself, there are other new transmissions on the market and on the way that are also significant. Mercedes has a new seven-speed automatic in production, Audi an electronically clutched and shifted manual.Ford and GM are working on a common six-speed automatic that will be installed in both brands of vehicles. While Ford may have called this the year of the car, it might have been more correct to call it the Year of the Transmission.A major part of what’s finally making these long-desired changes possible is the electronic content of those trannies. The on-vehicle con-trol electronics, sensor technology and software make what was a struggling technology ready for mainstream application.The basic benefits of improved-technology transmissions have been around for quite some time. The truth is that internal combustion en-gines are really efficient only over a fairly nar-row range of rpm. The tach in your car might suggest that the engine can run from idle to red-line and you’d never have to worry about it.While mechanically this is true, it’s not true in terms of fuel economy, emissions and reliability performance. The window for best emissions and economy may be less than 1000 rpm wide.This new generation of CVTs has about half the parts of a comparable automatic. In a world where simpler means less expensive and more reliable, this is good. One of the major subsys-tems that will disappear is the torque converter;it’s not needed with a CVT. When it comes to size, a CVT can be about the same physical size and weight as a standard five-speed manual transmission. Cutting the weight of the trans-mission in half has a direct impact on vehicle fuel economy.With a conventional transmission, three or four gear ratios are used to adapt engine speed to vehicle speed. This means that variations in engine rpm have to cover the range between As the need for improved fuel economy and componentsimplicity grows in importance, several automakers haverefocused their energies on CVTs to achieve both goals.Mike Dalecontinued on page 18This CVT, made by ZF Transmissions in Batavia,Ohio, is used in Europe on the Ford Focus. Ford has recently taken full control of that joint venture,signaling the ramp-up in CVT production and usage by Ford and other world automakers.P h o t o c o u r t e s y Z F T r a n s m i s s i o n seach gear. If there were more available gear ratios, the actual engine rpm op-erating range could be narrowed, keeping the engine in its most efficient operating range longer. The claims from automakers vary, but the general thrust of things is that with these im-proved-technology transmissions (not just CVTs), fuel economy can be im-proved from 6% to 10%. There are further claims of lower NO X emissions because the engine can be kept in a range where temperatures are low enough to prevent NO X emissions from forming.The value of six- and seven-speed transmissions is that they can handle the torque load of higher powered en-gines, such as the typical American V8. The range of gear ratios is wider with the new improved-technology trans-missions than it was with the old. The ratio span of the typical four-speed au-tomatic is between 3.5:1 and 4.0:1; Ford’s new CVT has a ratio span of 6.0:1.You can see how this works in thenew Mercedes seven-speed. MostOverdrive ratios are in the range of15% to 20%. This Mercedes transmis-sion has a 50% Overdrive. The outputof the transmission will be two full ro-tations for every engine rotation. Thisshould be good for high-speed, light-load, flat-land cruising. With Europeangasoline prices over five bucks a gallon,you can understand the concern theyhave over fuel economy.When you put it all together—betterfuel economy, lower emissions, fewerparts, lower cost (if not today, eventual-ly)—CVTs seem to make so much sensethat you wonder why we haven’t hadthem for a long time. The answer is reli-ability and torque limitations. VanDoorne’s original CVT used an upgrad-ed drive belt made of much the samematerials and construction as a V-belt.These belts originally had a life of about20,000 miles, when expected vehiclelife was maybe 80,000 to 100,000 miles.Even at a time when 50,000 miles wasacceptable for the life a VW Beetle en-gine, this was not good enough.More importantly, CVTs were notscalable. You couldn’t simply build abigger belt and have it work on a 6- or8-cylinder engine. The CVTs that havebeen out there have always been onsmall cars with relatively small dis-placements and torque-handling re-quirements. GM, for example, offersthem on 1.5- and 2.0L engines, and onthe 2.2L Ecotech engine used in Sat-urn’s VUE and ION.The road to an improved CVT has atleast two lanes. One of them is im-proved mechanical integrity, which hasbeen brought about by the use of met-al link belts and improved lubricants.In today’s belt systems, the belts oper-ate in compression, not in tension. Thismeans that the belt actually pushes thedrive pulley instead of pulling it.The development of these new beltshas been the result of extensive com-puter modeling. An outfit calledAbaqus Inc. has recently been talkingEye On Electronicsabout how its software was used by Honda to model the ef-fect the stiffness of the pulleys has on the life of the belts. Previously, it was assumed that the pulleys were perfectly stiff. When they actually programmed in the true material properties of the pulleys, they found that they did have some flexural stress, and that this could lead to misalignment of the belt. Computer simulations showed that stress on the belt could be lowered by 7% by making sure the pulley really was stiff enough to prevent misalignment.The second lane on the road to improved CVT durability and torque-handling capability is something called integrat-ed drivetrain torque control. While there are steady-state loads on any transmission, it’s the transient overloads, or spikes, that could possibly do damage.In GM’s VTi electronic CVT, torque management coordi-nation between the engine and transmission algorithms pro-vide overall transmission input torque protection. A recent SAE paper authored by GM engineers says that this soft-ware protects the variator system (their term for the pulleys and belt) from the shock loads during rock cycling and rolling garage shifts. It does this by controlling the combina-tion of input speed and torque limits needed to maintain the necessary belt clamp. They say their uniquely applied torque management strategy eliminates potential damage to the belt caused by inertia torque from sudden increases in wheel speed due to a loss of traction or harsh road inputs.Further electronic content is in the software used to con-trol the CVT. In GM’s case, fuzzy logic is used to determine driver intent, between acceleration and steady-state opera-tion. This allows the CVT to operate effectively during accel-eration, providing a linear acceleration linked to increasing engine speed. This prevents one of the “dislikes” about earli-er CVTs called motorboating. In those versions, the engine could accelerate up and down in an odd way while the pul-leys moved in and out. Integration of throttle control and transmission ratio control provides superior cruise control without inducing high engine speeds or cycling, even in rolling terrain. A grade braking logic provides speed control and enhances cruise control operation, allowing more accu-rate cruise set speeds.There have been some teething problems with the new-generation CVTs. Ford had hoped to have its CVTs in produc-tion a year ago. In January of this year, GM temporarily halted production of its CVT after making nearly 100,000 of them. Nearly 40% of Saturn VUEs and IONs were being equipped with CVTs at the time. There also have been reports of prob-lems with Honda’s Multitronic, especially in cases where power-increasing mods had been made to the engine.Some drivers have found the completely smooth shifting of the CVT to be a bit disconcerting. Companies like Nissan, Audi and BMW have programmed in “bumps,” so drivers would sense that the CVT was correctly “shifting” gears. From a service standpoint, there are a couple of things for you to know. Typically, the fluid fills in CVT transmissions are special for each particular transmission. Also, the recommend-ed service intervals are shorter for CVTs than for conventional automatics. Your customers need to know that these service intervals must be followed if they’re going to enjoy the long service life these transmissions can provide.。

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ansys计算接触不收敛力能很快的收敛，但力矩就是收敛不了，大家可有好办法以前用abaqus计算超弹接触都能很快的收敛ansys计算也就bonded容易收敛，其他的很难收敛，大家可有技巧收敛准则主要有力的收敛，位移的收敛，弯矩的收敛和转角的收敛。

一般用力的控制加载时，可以使用残余力的2-范数控制收敛；而位移控制加载时，最好用位移的范数控制收敛。

收敛精度默认为 0.1%，但一般可放宽至 5%，以提高收敛速度。

使用力收敛是绝对的,而位移收敛并不一定代表你的计算真的收敛,但很多情况下使用位移更容易得到想要的结果ANSYS中的收敛准则默认情况如下：cnvtol,lab,value,toler,norm,minref1）在solcontrol 为打开状态时，对于力和力矩来说是默认值为0.005；对于没有转角自由度的DOF，其默认值为0.05。

2）在solcontrol 为关闭状态时，对于力和力矩来说，其默认值为0.001。

默认情况下solcontrol 为打开状态，因此如果用户完全采用默认的话，对于力和力矩来说是默认值为0.005；对于没有转角自由度的DOF，其默认值为0.05。

在分析中追踪到沿荷载挠度曲线反向“漂移回去”，是一个典型的难题，这是由于太大或者太小的弧长半径引起的。

研究荷载-挠度曲线可以搞清楚这一点，。

然后可应用nsubst和arclen命令调整弧长半径大小和范围。

加快收敛的方法有一下几种：1可以增大荷载子步数 nsubst,nsbstp,nsbmn,carry2修改收敛准则 cnvtol,lab,value,toler,norm,minref3打开优化的非线性默认求解设置和某些强化的内部求解算法，solcontrol,key1,key2,key3,vtol（一般情况下，默认是打开的）4重新划分网格网格的单元不宜太大或太小一般在5～10厘米左右5 检查模型的正确性1) 关于位移判据当结构受力后硬化严重时,位移增量的微小变化将引起失衡力的很大偏差.另外,当相邻两次迭代得到的位移增量范数之比跳动较大时,将把一个本来收敛的问题判定为不收敛.所以在这两种情况下不能用位移准则.2) 关于力判据当物体软化严重时,或材料接近理想塑性时,失衡力的微小变化将引起位移增量的很大偏差.所以在这种情况下不能用失衡力判据如果单独用位移控制收敛,就可能出现第一次跌代后力和位移是收敛的,但第二次就跌代计算的位移很小,可能认为是收敛的解,实际离真正的解很远.应当使用力收敛检查或以位移为基础检查,不单独使用她们.convergence value 是收敛值，convergence norm是收敛准则。

ini pp 0 j=0fix pp j=0这样设置后是透水边界了底边界不透水,你可以不用管它了,默认为不透水边界我现在在三维中模拟基坑开挖，x(0~42) y(0~30) z(-40~0),初始水位在－3米处，我的初始水位命令这样写对不对啊？ini pp -3e4 grad 0 0 -1e4 range x 0 42 y 0 30 z -40 -3range -3.1 -2.9;;在开挖中需要降水，降至－7米，需开挖的区域为x(0~8) y(0~30)fix pp range x 8 42 y o 30 z -3.1 -2.9fix pp 0 range x 0 8 y 0 30 z -7.1 -6.9 pl contour pp可以显示孔隙水压力场，一般就认为就是渗流场吧！set flow on 即选择是否要进行渗流分析，其前提是要set fluid on方可以！off就是相反了。

但是，set fluid on以后不一定进行set flow on的计算，这点我的理解（有待证实）是，仅有set fluid on的话，就是把里面的pp当作是静水压力来处理的，而当set flow on 打开以后，就可以进行真正意义上的渗流分析了！再一个，set flow on的一个前提必须设定perm值（渗透系数），否则程序无法继续进行！而set fluid on就没有那么严格，只要是config fluid 以及设定模型以及fmod以后即可以开始计算了。

set mech on就表示把力学计算这部分打开，在默认的情况下，是打开的。

在流固耦合有一节中讲到，当只要使系统产生水压力的分布，而不需要由于机械变形（mechanical deformation）而产生的pp的时候，就必须要set mech off，也就是说这个时候只有fluid的计算，而没有mechanical 的计算了。

帮助的第ftd138.pdfbulk modulus, K 390 MPa 体积模量（土质比较硬）shear modulus, G 280 MPa 剪切模量soil dry density, ρd 1200 kg/m3 土的密度water density, ρw 1000 kg/m3 水密度wall density, ρwal 1500 kg/m3 档土墙的密度permeability, k 10−12 m2/Pa-s 渗透系数porosity, n 0.3 孔隙率fluid bulk modulus, Kf 2.0 GPa 流体的体积模量;-----以下是命令流config fluid ;设置流体算法gen zone brick p1 12 0 0 p2 0 12 0 p3 0 0 12 size 12 12 12 rat 1 1 1group soil ;设置土组group excavate range x 0 4 y 0 4 z 0 5 ;设置开挖范围组group wal1 range x 4 5 y 0 5 z 0 7 ; 设置档土墙1 组group wal2 range x 0 4 y 4 5 z 0 7 ;设置档土墙2 组group wall range group wal1 any group wal2 any ;档土墙1 和2 合并为一个档土墙组; --- fluid flow model --- 流体模型model fl_iso ;各项同性流体prop perm 1e-12 poro 0.3 ;设置渗透系数和？？比or ？？率ini fdensity 1e3 ; 初始化水密度ini fmod 2.0e9 ftens -1e-3 ; 初始化水的体积模量及？？model fl_null range group excavate ; 开挖部分没有水流model fl_null range group wall ;档土墙不渗水jini pp 0 grad 0 0 1e4 ;初始化孔隙水压力fix pp range z -0.1 0.1 ;约束应该是整个模型的底部吧？fix pp range x -0.1 4.1 y -0.1 4.1 z 4.9 5.1 ;开挖部分也给约束住了，而其他的地方不管，为什么要约束开挖部分？model elas ; 弹塑性prop bul 3.9e6 shea 2.8e6 ;设置体积模量和剪切模量，这两个必须model null range group excavate ;力学模型的开挖ini density 1.2e3 ;初始化密度，应该是土的密度ini density 1.5e3 range group wall ;初始化墙（档土墙）的密度fix x range x -.1 .1 ;施加约束，据说差分法约束0 的时候，必须取一个-0.1<0<0.1,范围fix x range x 11.9 12.1 ;施加约束，或者叫做边界条件fix y range y -.1 .1 ;施加约束fix y range y 11.9 12.1fix z range z 11.9 12.1ini szz 0 grad 0 0 -1.5e4 ;z方向的应力大一些ini sxx 0 grad 0 0 -1.2e4 ;水平方向的，小一些ini syy 0 grad 0 0 -1.2e4apply nstress 0 grad 0 0 -1.2e4 range x 0.0 4.0 y 3.9 4.1 z 0.0 5.0apply nstress 0 grad 0 0 -1.2e4 range x 3.9 4.1 y 0.0 4.0 z 0.0 5.0apply nstress -7.5e4 range x 0.0 4.0 y 0.0 4.0 z 4.9 5.1; --- setting --- 设置set gravity 0 0 10 ;设置重力加速度solve force 1 ; check initial equilibrium 求解平衡; --- excavation --- 开挖set fluid off ;关闭水apply nstress 0 grad 0 0 -1.e4 range x 0.0 4.0 y 3.9 4.1 z 0.0 5.0apply nstress 0 grad 0 0 -1.e4 range x 3.9 4.1 y 0.0 4.0 z 0.0 5.０apply nstress -5.e4 range x 0.0 4.0 y 0.0 4.0 z 4.9 5.1solve ;force 1 ;求解save exc1.sav ; 保存; --- drainage --- 排水apply remove nstress ;撤掉刚才的压力def relaxsetup ;定义一个释放函数的参数step0 = stependrelaxsetup ;调用def relax ;定义一个释放函数rstep = step - step0if rstep < ncyc thenrelax=1.0-(float(rstep)/float(ncyc))elserelax=0.0endifendset ncyc=1000；先赋值，然后调用apply nstress 0 grad 0 0 -1e4 his relax range x 0.0 4.0 y 3.9 4.1 z 0.0 5.0 apply nstress 0 grad 0 0 -1e4 his relax range x 3.9 4.1 y 0.0 4.0 z 0.0 5.0 apply nstress -5e4 his relax range x 0.0 4.0 y 0.0 4.0 z 4.9 5.1cyc ncycsolve; --- percolation --- 渗透set fluid on ;设置水算法Fluentfix pp 0 range x -0.1 4.1 y -0.1 4.1 z 4.9 5.1 ;施加孔隙水压力cyc 9000 ;循环save exc3.sav ;保存你是想做渗流分析还是静力分析渗流分析的话用config fluid做流固耦合分析把手册中几个例子搞明白应该收获很大提醒生成初始应力场时水平应力＝k0×竖向有效应力＋水应力如果仅仅是静力分析只要设定稳定水位手动干湿密度就行与Interface相关的命令总结（望续）最近用到这个了，因为初学尝尽苦头，以前整理的贴出来，望有别的还可以跟帖，simwe9j2g2K0`$^.p;j9@仿真分析,有限元,模拟,计算,力学,航空,航天,ANSYS,MSC,ABAQUS,ALGOR,Adina,COMSOL,FEMLAB,Matlab,Fluent,CFD,CAE,CAD,CAM7v6Q8E*O1M%R4~ 1）interface后面可以使用range关键字，用来限定其范围；range id用来设定界面元或节点的开始和最后的标识号码；2l5M:Y!T$asimwe2）interface命令用来定义两个或多个子网格之间的界面，这些界面可以滑动、分离。