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yangshuyin

新虫 (初入文坛)

应助: 0 (幼儿园)
金币: 10.4
帖子: 2
在线: 1.2小时
虫号: 936249

[交流] 【求助】芯片在高过载应力下的受力仿真模拟

如题，最近跟着导师后面做项目
我做的这一块是针对弹上芯片受力情况的模拟
使用的工具是Ansys12.0
由于是计算机专业的以前从来没有接触过ANSYS软件对力学也是一窍不通
自己搞了一段时间成效甚少只好向各位路过的大神求教啊！！！
/UNITS,SI
/FILNAME,MCM_CHIP
/TITLE,2D OVERLOAD SIMULATION OF MULTICHIP MODULE

!定义封装外壳
*SET,ENCAP_WL,14.1E-3
*SET,ENCAP_HEIGHT,1E-3

!定义芯片尺寸
*SET,CHIP_WL,ENCAP_WL/2
*SET,CHIP_HEIGHT,ENCAP_HEIGHT/4

!定义引脚尺寸
*SET,PIN_X1,1E-3 !0.4E-3
*SET,PIN_X2,0.2E-3
*SET,PIN_X3,0.4E-3
*SET,PIN_HEIGHT,0.8E-3
*SET,PIN_THICK,4E-5
*SET,PIN_WIDTH,0.3E-3
*SET,PIN_DIST,0.8E-3
*SET,PIN_NB,16

!单元类型
/PREP7
ET,1,SOLID95
!设定为平面应变问题？
!KEYOPT,1,3,2

!定义芯片材料属性
MP,EX,1,131E9
MP,PRXY,1,0.30
MP,DENS,1,2300
!MP,ALPX,1,2.8E-6

!定义芯片下焊料凸点的材料属性
MP,EX,2,30E9
MP,PRXY,2,0.35
MP,DENS,2,7298

!定义封装材料
MP,EX,3,3E9
MP,PRXY,3,0.38
MP,DENS,3,980

!定义铜属性
MP,EX,4,115E9
MP,PRXY,0,33
MP,DENS,4,8900

BLOCK,-ENCAP_WL/2,ENCAP_WL/2,-ENCAP_WL/2,ENCAP_WL/2,0,ENCAP_HEIGHT

BLOCK,-CHIP_WL/2,CHIP_WL/2,-CHIP_WL/2,CHIP_WL/2,ENCAP_HEIGHT/2,CHIP_HEIGHT

K,100,-ENCAP_WL/2+ENCAP_WL/18,-ENCAP_WL/2+0.7*PIN_X1,ENCAP_HEIGHT/2
K,101,-ENCAP_WL/2+ENCAP_WL/18,-ENCAP_WL/2-0.3*PIN_X1,ENCAP_HEIGHT/2
K,102,-ENCAP_WL/2+ENCAP_WL/18,-ENCAP_WL/2-0.4*PIN_X1,0
K,103,-ENCAP_WL/2+ENCAP_WL/18,-ENCAP_WL/2-0.8*PIN_X1,0

k,104,-ENCAP_WL/2+ENCAP_WL/18+PIN_WIDTH,-ENCAP_WL/2+0.7*PIN_X1,ENCAP_HEIGHT/2
K,105,-ENCAP_WL/2+ENCAP_WL/18,-ENCAP_WL/2+0.7*PIN_X1,ENCAP_HEIGHT/2+PIN_THICK

LSTR,100,101
LSTR,101,102
LSTR,102,103
LSTR,100,104
LSTR,100,105

K,1000,ENCAP_WL/2-0.7*PIN_X1,ENCAP_WL/2-ENCAP_WL/18,ENCAP_HEIGHT/2
K,1001,ENCAP_WL/2+0.3*PIN_X1,ENCAP_WL/2-ENCAP_WL/18,ENCAP_HEIGHT/2
K,1002,ENCAP_WL/2+0.4*PIN_X1,ENCAP_WL/2-ENCAP_WL/18,0
K,1003,ENCAP_WL/2+0.8*PIN_X1,ENCAP_WL/2-ENCAP_WL/18,0

k,1004,ENCAP_WL/2-0.7*PIN_X1,ENCAP_WL/2-ENCAP_WL/18-PIN_WIDTH,ENCAP_HEIGHT/2
K,1005,ENCAP_WL/2-0.7*PIN_X1,ENCAP_WL/2-ENCAP_WL/18,ENCAP_HEIGHT/2+PIN_THICK

LSTR,1000,1001
LSTR,1001,1002
LSTR,1002,1003
LSTR,1000,1004
LSTR,1000,1005

1。首先定义了一些基本的单元，内部的是硅材质的芯片，外面是封装材料，在外围的是两根引脚，只是画了线，没有用脚本写完
2。手动对线先面扩展，后是面到体的扩展，然后沿横纵坐标复制出其他引脚，最后生成整个结构
3。再对结构进行网格划分
4。对引脚施加DOF全约束
5。在x y z三个方向上施加重力加速度值分别使用的是10g
6。求解

求解过程中出现很多种类型的错误
*** ERROR ***                         CP =    166.750 TIME= 09:15:49
Sparse Matrix The solver has failed.  Please check the error file fodr
possible causes.

*** ERROR ***                         CP =    166.750 TIME= 09:15:49
Bisection may be activated if it is a nonlinear analysis.

*** ERROR ***                         CP =    170.328 TIME= 09:01:30
There is not enough memory for the Sparse Matrix solver to proceed.
Please increase the virtual memory on your system and/or increase the
work space memory and rerun ANSYS.  The memory currently allocated by
ANSYS = 764 MB.  The memory allocation attempted = 376 MB.  The
largest block of ANSYS memory available for the Sparse Matrix solver =
311 MB.

*** WARNING ***                      CP =    33.609 TIME= 08:56:12
Mid-nodes of some elements have been modified to lie on straight edges
because of distortion with the original mid-nodes.  This condition is
sometimes eliminated by tetrahedron element improvement when enabled.
Issue ESEL,,STRAIGHTENED to select such elements for listing or
plotting.

*** WARNING ***                      CP =    38.734 TIME= 08:56:24
Shape testing revealed that 1 of the 308131 new or modified elements
violate shape warning limits.  To review test results, please see the
output file or issue the CHECK command.

*** WARNING ***                      CP =    54.984 TIME= 08:57:44
Previous testing revealed that 1 of the 308131 selected elements
violate shape warning limits.  To review warning messages, please see
the output or error file, or issue the CHECK command.

*** ERROR *** --最核心的错误@@
A small negative equation solver pivot term has been encountered at the
UZ degree of freedom of node 2194.  Check for an insufficiently
constrained model.

我感觉还是前面部分建模部分或者是网格划分还有约束的定义上出了问题，影响了后面结果的计算，请大家帮忙看一看，因为是初学，很多问题也许犯的很低级，请大家帮帮忙，谢谢了！！！！

[ Last edited by yangshuyin on 2010-11-16 at 11:08 ]

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