Abaqus 導(dǎo)出單元?jiǎng)偠染仃嚭腿謩偠染仃?/h1>

首次創(chuàng)建：2023.7.29
最后更新：2023.7.29
如有什么改進(jìn)的地方，歡迎大家討論！

詳細(xì)情況請(qǐng)查閱：Abaqus Analysis User’s Guide

一、Abaqus 導(dǎo)出單元?jiǎng)偠染仃?/h2>

1.生成單元?jiǎng)偠染仃嚪椒?/h3>

導(dǎo)出單元?jiǎng)偠染仃囆枰薷?code>inp文件，先在abaqus中創(chuàng)建一個(gè)單元集合，這個(gè)集合是你想導(dǎo)出的單元集合，這里我創(chuàng)建的是Element_ALL。然后生成inp文件，在inp文件中的step關(guān)鍵字對(duì)中添加如下一行指令：
*Element Matrix Output, Elset=Element_ALL, File Name=ElementStiffness, Output File=User Defined, stiffness=yes

.....
.....
*Restart, write, frequency=0
** 
** FIELD OUTPUT: F-Output-1
** 
*Output, field, variable=PRESELECT
** 
** HISTORY OUTPUT: H-Output-1
** 
*Output, history, variable=PRESELECT
** 添加下面這一行
*Element Matrix Output, Elset=Element_ALL, File Name=ElementStiffness, Output File=User Defined, stiffness=yes
*End Step

2.單元?jiǎng)偠染仃囄募袷椒治?/h3>

這樣在abaqus提交任務(wù)計(jì)算后，就會(huì)在abaqus 的當(dāng)前項(xiàng)目工作目錄下生成一個(gè)ElementStiffness.mtx文件，其格式如下：

**
** ELEMENT NUMBER          1 STEP NUMBER        1 INCREMENT NUMBER        1
** ELEMENT TYPE  C3D4    
*USER ELEMENT, NODES=         4, LINEAR
** ELEMENT NODES
**          2,          1,          9,          81,          2,          3
*MATRIX,TYPE=STIFFNESS127.06125836015    ,0.0000000000000    ,  183.76386705487    0.0000000000000    , -121.64117806010    ,  388.01179556583    -39.618685020706    , -22.681043477885    ,  48.656471224038    ,  60.711115702304    -15.120695651923    , -96.321293715418    ,  80.880129060096    ,  37.801739129808    92.212564977143    ,32.437647482692    ,  60.499604560096    , -81.962788877760    , -13.159037040064    -19.738555560096    ,  42.381078873928    -173.27005949011    ,  0.0000000000000    ,  0.0000000000000    ,  28.116306917523    0.0000000000000    , -53.846153846154    ,  287.62647738911    0.0000000000000    , -173.27005949011    ,  80.769230769231    ,  0.0000000000000    28.116306917523    , -80.769230769231    ,  0.0000000000000    ,  287.62647738911    0.0000000000000    ,  121.15384615385    , -606.44520821538    , -80.769230769231    -121.15384615385    ,  98.407074211329    ,  0.0000000000000    ,  0.0000000000000    1006.6926708619    ,85.827486150661    ,  22.681043477885    , -48.656471224038    , -49.208737599120    -22.681043477885    ,  34.567543403526    , -142.47272481653    ,  0.0000000000000    80.769230769231    ,  105.85397626499    15.120695651923    ,  85.827486150661    , -40.008181769231    , -15.120695651923    -24.007578179248    ,  40.008181769231    ,  0.0000000000000    , -142.47272481653    0.0000000000000    ,  0.0000000000000    ,  80.652816845114    -32.437647482692    , -60.012272653846    ,  300.39620152731    ,  45.271796585256    60.012272653846    , -58.825364207497    ,  53.846153846154    ,  0.0000000000000    -498.65453685784    , -66.680302948718    ,  0.0000000000000    ,  257.08369953803  ........

從內(nèi)容可以看出*MATRIX,TYPE=STIFFNESS后面的就是一個(gè)單元?jiǎng)偠染仃?#xff0c;其形式為下三角形式。上面是一個(gè)線(xiàn)性四面體的單元?jiǎng)偠染仃?#xff0c;由于線(xiàn)性四面體有4個(gè)節(jié)點(diǎn)，每個(gè)節(jié)點(diǎn)有3個(gè)自由度，所以單元?jiǎng)偠染仃嚨木S度是12x12的：
$$k{e}_{12x12}$$
整理后如下所示：

127.06125836015
0.0000000000000	183.76386705487
0.0000000000000	-121.64117806010	388.01179556583
-39.618685020706	-22.681043477885	48.656471224038	60.711115702304
…	…	…	…	…

二、Abaqus 導(dǎo)出全局剛度矩陣

1.生成全局剛度矩陣方法

在inp文件最后添加一個(gè)輸出全局剛度矩陣的step，如下所示：

....
....
*Output, field, variable=PRESELECT
** 
** HISTORY OUTPUT: H-Output-1
** 
*Output, history, variable=PRESELECT
** 導(dǎo)出單元?jiǎng)偠染仃?*Element Matrix Output, Elset=Element_ALL, File Name=ElementStiffness, Output File=User Defined, stiffness=yes
**
*End Step**
** 導(dǎo)出全局剛度矩陣
*Step, name=GlobalStiffnessMatrix
*MATRIX GENERATE, STIFFNESS
*MATRIX OUTPUT, STIFFNESS, FORMAT=COORDINATE
*End Step
**

2.全局剛度矩陣文件格式分析

同樣提交任務(wù)后將在工程的工作目錄下生成一個(gè)以你任務(wù)名稱(chēng)命名的mtx文件：如我的任務(wù)名稱(chēng)為Job-exportStiffness-globalstiffness那么將生成Job-exportStiffness-globalstiffness_STIF2.mtx文件，這個(gè)文件就存儲(chǔ)著全局剛度矩陣。部分內(nèi)容如下：

1 1  3.405254068249726e+02
1 2  6.072817378766025e+01
2 1  6.072817378766025e+01
1 3  1.269469880224359e+02
3 1  1.269469880224359e+02
1 4 -5.756613438782665e+01
4 1 -5.756613438782665e+01
1 5 -3.763929516105769e+01
5 1 -3.763929516105769e+01
1 6  8.076923076923076e+01
6 1  8.076923076923076e+01
1 7  6.181074378769931e+01
7 1  6.181074378769931e+01
....
....

可以看出這是采用三元數(shù)組的方式來(lái)存儲(chǔ)的，即一行數(shù)據(jù)前面?zhèn)€為矩陣的（x,y）位置索引，最后一個(gè)為該索引位置的值。