t***e
发帖数: 291 | 1 http://www.simwe.com/cgi-bin/ut/topic_show.cgi?id=43664&h=1&bpg=1&age=0
由垄断走向竞争
—UGS PLM Solutions成为另一家Nastran软件供应商
Nastran的起源
Nastran，即NASA 结构分析系统，是1966年由NASA发起，邀请软件开发商一起
开发的一个用于航空、航天飞行器及发射系统的结构分析通用求解器，称为COSMIC
NASTRAN。COSMIC NASTRAN 是放在public domain上的公开发售版本， NASTRAN是NASA
的注册商标。
1972年，MSC 获得了一个版本的COSMIC NASTRAN，并推出了商业化产品 MSC
NASTRAN。八十年代，又有另外两家公司UAI、 CSAR基于NASA的COSMIC NASTRAN 推出
了各自的商业版本。当时，市场上主要三家Nastran供应商为MSC，UAI和CSAR。
MSC.Nastran垄断引起客户申诉
1999年，MSC 收购了UAI 和 CSAR， |
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s*i
发帖数: 5025 | 2 Good thinking!
NASTRAN是NASA
Nastran将继续使用通用的Nastran
场中来，UGS成为唯一专业CAD/CAE软件一体化的全产品生命周期解决方案供应商。Nastra
n |
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p**e
发帖数: 126 | 3 classic laminate theory does not support in of plane torsion. therefore the
6th degree of freedom has to be zero. I don't know exactly how nastran is
implemented. but that might be the reason. in abaqus such problem does
not exist. in both abaqus and nastran, laminate is just add add-on to the
classic shell theory. no special treatment necessry just have to integrate
across the layers.
also in nastran manual, it seems only the cquad4 supports composite.
abaqus is much stronger in composite than |
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t***e
发帖数: 291 | 4 看看nastran的用户，就是FEAer的潜在雇主。 |
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r********o
发帖数: 1423 | 5 就是laminate这个单元，在分层的时候，每一层nastran是当作什么处理的？是不是就是
把每一层相当于看作是板单元（假设是Quadrilateral)里面的CQUAD4或者CQUADR?我想如
果把每层的材料性质都输成一样的isotropic材料的话，那么laminate单元应该就相当于
同厚度的板单元。
如果这个假设成立的话，那么由于CQUAD4的节点自由度是5，CQUADR的节点自由度是6，
laminate单元的节点自由度应该和自己选的Quadilateral的自由度是一致的。（CQUAD4或
者CQUADR可以在run model之前的advanced option里面选），由于CQUADR是考虑in plane
loading的，我就选了CQUADR,结果run出来以后，后处理项里面就没有laminate各层的
data了。。。
俺正在给公司里面写FEA manual,才疏学浅，万望各位大牛指教。 |
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p**e
发帖数: 126 | 6 the laminate theory assumes the classic plate strain distribution across the
thickness. therefore for the the entire laminate, there is no separate
DOF for each layer. only that the integration is done for each layer to get
the appropraite K. after getting the solution, then back calculate the
stress/strain at each integraion point at each layer.
read through theory manual, and you will see how it is treated. the laminate
theory incorperated in all finite element codes (ansys, abaqus, nastran) i |
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r********o
发帖数: 1423 | 7 Thanks for yuor reply, hehe, I was dealing with Laminate theory and thin plate
/shell theory previously for my research. Though sandwich structure it is
treated, the one layer(mid-plane) assumption is taken inside FEA. My question
is for the DOF of laminate, when I select the CQUAD4(5 dof) or CQUADR(6 dof)
for the solution, the data for the failure index for each layer are only
available for CQUAD4, while not available for CQUADR. Therefore, I was
confused about the way how Nastran treats the La |
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j**u
发帖数: 6059 | 8 ☆─────────────────────────────────────☆
caoer (caoer) 于 (Sat Jun 11 09:25:53 2011, 美东) 提到:
民科博导开公司了，祝顺利。。。
☆─────────────────────────────────────☆
tjhaven (无名) 于 (Sat Jun 11 16:38:38 2011, 美东) 提到:
坑兄，这个美国工资好像太低了吗？芝加哥搞计算的博士怎么样都要6~8万刀吗？计算机硕士都要6万朝上了。
而且这个表现都是老板说了算，标准很难确定。我给你个建议，要真想搞公司，博士8.5万，硕士7万保底。bonus和奖励另算。干得好有年薪的30%。
要不就别玩了。没有投入时没有产出的。
☆─────────────────────────────────────☆
tjhaven (无名) 于 (Sat Jun 11 16:44:51 2011, 美东) 提到:
怎么能推上十大？让大家看看？
☆─────────────────────────────────────☆
... 阅读全帖 |
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i******d
发帖数: 565 | 9 呵呵，不至于都被淘汰吧。。
我力学phd毕业十年了，用过不少大型的有限元软件：ansys, abaqus, nastran/patran
, algor, cosmos等。我觉得每个软件几乎都有其特点和较好的应用领域。比如nastran
航空航天，abaqus非线性。ansys商业通用等。还有非常多的特定行业的有限元软件。
这些基本上都很难被淘汰的。因为有限元应用的领域非常多非常广泛，不可能有一个软
件能够囊括所有的领域通吃别的软件的。
我目前用ansys有6年多了，感觉相对来说这个软件是商业应用最广泛的。不过它也不可
能淘汰别的软件的。这些公司的软件代码都是几十年不断发展起来的。nastran发展至
今都快50年了，期间大量的科学家和工程师来完善和增强这个软件。
不清楚你的公司要具体怎么做和做什么，如果你的公司想淘汰掉这些公司，那是绝不可
能的。你能站有一席之地就非常不错了。
你的口气太大了。 |
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p**e
发帖数: 126 | 10 in term of capability, nastran is the worst among the big three ansys abaqus
and nastran. and it is the least customizeable. however, it is proven, widely
used since the beginning of FEM. aerospace would be reluctant to switch to
other codes. but for other new field like medical etc, ansys and abaqus are
more
popular. now, nastran is trying to make it up by integrating ls-dyna and
marc into it to compete with abaqus.
on the other hand patran is still a pretty good one
ansys/ |
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a******n
发帖数: 98 | 11 I built a structural model for an air vehicle. As it contains tension-only
element, nonlinear analysis need to be applied. I don't know how to
constrain six degrees of freedom in order to remove rigid body motion.
There are some symmetric conditions existing, but I still can not constrain
six degrees of freedom. Someone suggested the "inertial relif" function of
Nastran. Even in Nastran, it sounds like that "inertial relief" is not
working for nonlinear model. (I am not familar with Nastran). Is |
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w*********h
发帖数: 664 | 12 对于市面上的一些有限元软件，再结合各位版友的观点，我再多罗嗦几句。。。
Nastran是处理各类线性问题的行业标准，虽然现在对于线性问题的研究已经没有更多
的理论突破，而且市面上很多的有限元软件都可以处理线性问题，但是从求解线性问题
的精准度，求解的效率（包括多cpu并行求解），包括NASTRAN特有专利技术如处理气动
力学的功能等等，都只能让其他软件望其项背。但是现在有限元的发展方向已经把目光
更多的投向非线性问题，非线性材料，各种各样的非线性接触问题，也包括各种流固耦
合的问题。在MSC的整个产品体系中，如果说NASTRAN是处理线性问题的，那么MARC是用
来处理非线性静力学问题的，而DYTRAN是用来处理非线性动力学问题的，如鸟撞，水下
爆炸，导弹出入水等，也包括流体固体的单双向耦合（FSI）问题。但是自从1999年
MARC被MSC收购之后，MSC致力于各类产品的整合而降低了对MARC研发的重视程度，所以
从功能上来看，MARC现在已经排不上一流的非线性有限元软件了。
对于ABAQUS，个人认为是目前市面上最优秀的通用非线性有限元软件。传统上看，
ABAQUS有三大模块，AB |
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d*********e
发帖数: 3835 | 13 Direct Hire with benefits. 3 different experience levels - multiple openings
Position Purpose:
Works on engineering projects containing critical problems, the solution of
which requires major technological advances and extensive related
development
Principal Duties and Responsibilities
Essential Functions:
1) Responsible for an entire engineering project of major complexity within
established scope
2) Makes technical decisions and recommendations that are recognized as
authoritative and have an ... 阅读全帖 |
|
r********o
发帖数: 1423 | 14 I believe since ansys sells at cheaper price than Nastran/Abaqus, the ansys
company wants to collect more money in customer care and technical help as a
complement, hehe
for MSC Nastran, I know that for each year, the technical help fee for one
license is more than 10K, not sure how much ANSYS requires. |
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g*****y
发帖数: 1350 | 15 autocad, solid works, catia, pro/e, ansys, abacus, nastran, matlab....... |
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s*******x
发帖数: 427 | 16 Position: NVH/CAE Engineer
Location: Dearborn, MI
Altair ProductDesign is a global, multi-disciplinary product development
consultancy of more than 700 designers, engineers, scientists, and creative
thinkers. As a wholly owned subsidiary of Altair Engineering, Inc. (www.
altair.com), this cross-functional organization is best known for its
leadership in combining human and machine creativity to fuel innovation,
automate processes, and develop new methods. Altair ProductDesign firmly
advocate... 阅读全帖 |
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l****c
发帖数: 838 | 17 I suggest you add more keywords, such as what software tools you used.
For mechanical design, such as Solid works/Autocad...
For FEA, Ansys, Nastran????
I had an onsite interview yesterday, they looked at the keywords on resume.
I was selected fro onsite because my former company used to be one of their
customers. |
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h****g
发帖数: 74 | 18 如题，如果你想找有限元的工作，请发简历到h****************[email protected]
我会forward你的简历，他们公司pay的还可以。要求如下(可以适当放宽）：
Highly Desired:
• Requires an accredited engineering MS or PhD degree (typically
Mechanical) or equivalent industrial experience and good working knowledge
of numerical simulation software tools including structural analysis, but
not limited to.
• Incumbents have usually gained 2 to 5 years of industry experiences
or gained Ph.D in the area of nonlinear structural analysis area.
• The perso... 阅读全帖 |
|
s*******x
发帖数: 427 | 19 Position: NVH/CAE Engineer
Location: Dearborn, MI
Altair ProductDesign is a global, multi-disciplinary product development
consultancy of more than 700 designers, engineers, scientists, and creative
thinkers. As a wholly owned subsidiary of Altair Engineering, Inc. (www.
altair.com), this cross-functional organization is best known for its
leadership in combining human and machine creativity to fuel innovation,
automate processes, and develop new methods. Altair ProductDesign firmly
advocate... 阅读全帖 |
|
t*****c
发帖数: 3 | 20 我们公司位于Novi,Michigan的 Technical Center招收一名NVH方面的Mechanical
Engineer.
如有意向，请先把简历发到我的E-mail。
t*****[email protected]
• Evaluate and develop vehicle NVH (Noise, vibration and harshness)
performance
• Conduct experimental NVH investigations (Modal analysis, Transfer
Path analysis, Sound Quality analysis, etc.) in support of anti-vibration
product development.
• Benchmark competitive vehicles for technology and trends
• Build and analyze CAE model to improve product NVH a... 阅读全帖 |
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t*****c
发帖数: 3 | 21 我们公司位于Novi,Michigan的 Technical Center招收一名NVH方面的Mechanical
Engineer.
如有意向，请先把简历发到我的E-mail。
[email protected]
(function(){try{var s,a,i,j,r,c,l,b=document.getElementsByTagName("script");l=b[b.length-1].previousSibling;a=l.getAttribute('data-cfemail');if(a){s='';r=parseInt(a.substr(0,2),16);for(j=2;a.length-j;j+=2){c=parseInt(a.substr(j,2),16)^r;s+=String.fromCharCode(c);}s=document.createTextNode(s);l.parentNode.replaceChild(s,l);}}catch(e){}})();
/* ]]> */
• Evaluate and develop vehicle ... 阅读全帖 |
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e****s
发帖数: 113 | 22 【 以下文字转载自 Working 讨论区 】
发信人: mydreamsg (mydreamsg), 信区: Working
标 题: 在石油行业，感觉快被裁员了，不知道如何办最好？
发信站: BBS 未名空间站 (Wed Dec 9 05:27:50 2015, 美东)
油价低迷了一年，我们公司做油井服务和结构设计，所以油价对我们公司影响十分大，
这一年只有零星的小订单。前两个月，已经裁员过一次了，我侥幸留了下来。马上就有
下一波裁员，被裁的可能性很大。
我学的机械专业，硕士，在公司用有限元软件比如ansys,nastran,sacs做结构分析。现
在38岁，上有老，下有小，有身份。
看分析，估计油价还要低迷5年，现在很焦虑：
1）转行读一个CS 的master，可行么？
2）换去别的行业，比如汽车什么的，但是估计薪水会降低很多。
求建议。 |
|
W***n
发帖数: 11530 | 23 Principal Composite Structure Analysis Engineer Job
Orbital ATK 163 reviews - Irvine, CA
Job ID: TS20160405-35223
Description:
With annual revenues in of nearly $4.5 billion, over 12,000 employees, and
operations in about 20 states, Orbital ATK is a company on the move. Our
mission is to ensure that our customers accomplish their mission — whether
it’s a technological breakthrough, a satellite launch, or protecting our
nation. The company is the world’s leading supplier of solid rocket motors,
a... 阅读全帖 |
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b******g
发帖数: 1 | 24 Aerospace company in Winston-salem, NC, 27106 has 2 CAE analyst openings:
1, Crash position: LS-DYNA and H2/H3 FTSS/LSTC dummy experience.
2, Shape optimization position: Altair OptiStruct. MSC Adams, Marc, Nastran
experience preferred.
Ideally, candidate need to have both experience, but excellent work
experience in one area is OK also. Hypermesh and Patran skill is needed also
. Any seat experience is desired.
Please send the resume or your contact information to beflying@mycingular.
blackerry |
|
m*******g
发帖数: 63 | 25 油价低迷了一年，我们公司做油井服务和结构设计，所以油价对我们公司影响十分大，
这一年只有零星的小订单。前两个月，已经裁员过一次了，我侥幸留了下来。马上就有
下一波裁员，被裁的可能性很大。
我学的机械专业，硕士，在公司用有限元软件比如ansys,nastran,sacs做结构分析。现
在38岁，上有老，下有小，有身份。
看分析，估计油价还要低迷5年，现在很焦虑：
1）转行读一个CS 的master，可行么？
2）换去别的行业，比如汽车什么的，但是估计薪水会降低很多。
求建议。 |
|
m*******g
发帖数: 63 | 26 你的成绩很好了；要直接进的话需要熟人推荐。
做FEA的话，上述你投的几个企业一般是master，PHD来做，FEA这事，其实没啥用处，
不同的人做，和同一个人在不同的心情下做，结果差别很大，所以人们倾向于相信PHD
的人做的。正式的设计中，都是用规范和经验公式，因为算的结果稳定、可靠、快速，
等你算FEA，很慢，你心血来潮，使用不同的简化，换一个mesh和边界条件，结果又变
了，设计的人会抓狂。
我就做了2年的FEA了，搞了3个正式的projects,ANSYS，ABAQUS，NASTRAN，LS-DYNA都
用过，用老板的话，总结起来，就是“锦上添花”，没你这花，也行，有你这花，好看
些。工程中，靠经验更快，更准确，依靠你FEA去解决问题，基本是扯淡。一是没个5年
以上经验你算不准，二是你建模慢，三是你算准算快了，没PHD，别人不敢相信。
你如果找不到熟人推荐，可以考虑读NUS offshore centre的msc,短平快，想进
offshore起码有90%的概率。推荐去搞设计，不要搞FEA，费时费力没成效。 |
|
e****s
发帖数: 113 | 27 【 以下文字转载自 Working 讨论区 】
发信人: mydreamsg (mydreamsg), 信区: Working
标 题: 在石油行业，感觉快被裁员了，不知道如何办最好？
发信站: BBS 未名空间站 (Wed Dec 9 05:27:50 2015, 美东)
油价低迷了一年，我们公司做油井服务和结构设计，所以油价对我们公司影响十分大，
这一年只有零星的小订单。前两个月，已经裁员过一次了，我侥幸留了下来。马上就有
下一波裁员，被裁的可能性很大。
我学的机械专业，硕士，在公司用有限元软件比如ansys,nastran,sacs做结构分析。现
在38岁，上有老，下有小，有身份。
看分析，估计油价还要低迷5年，现在很焦虑：
1）转行读一个CS 的master，可行么？
2）换去别的行业，比如汽车什么的，但是估计薪水会降低很多。
求建议。 |
|
|
|
t*****z
发帖数: 812 | 30 astran out le
GM has replaced it with Hyperworks/Radiossarter16 (老干部) 的大作中提到: 】 |
|
r***y
发帖数: 248 | 31 【 以下文字转载自 Working 讨论区 】
发信人: mydreamsg (mydreamsg), 信区: Working
标 题: 在石油行业，感觉快被裁员了，不知道如何办最好？
发信站: BBS 未名空间站 (Wed Dec 9 05:27:50 2015, 美东)
油价低迷了一年，我们公司做油井服务和结构设计，所以油价对我们公司影响十分大，
这一年只有零星的小订单。前两个月，已经裁员过一次了，我侥幸留了下来。马上就有
下一波裁员，被裁的可能性很大。
我学的机械专业，硕士，在公司用有限元软件比如ansys,nastran,sacs做结构分析。现
在38岁，上有老，下有小，有身份。
看分析，估计油价还要低迷5年，现在很焦虑：
1）转行读一个CS 的master，可行么？
2）换去别的行业，比如汽车什么的，但是估计薪水会降低很多。
求建议。 |
|
|
r********o
发帖数: 1423 | 33 现在想要得一批软件都找不到，怀念啊...
patran/nastran,UG和Catia，那位大侠有麻烦告知在下一声 |
|
v****e
发帖数: 41 | 34 我查了一下，Nastran可以算。但是我们这儿只有ABAQUS。 用Mises没有问题，主要是要
求用Tresca准则。
UMAT是ABAQUS的用户材料子程序。 |
|
p**e
发帖数: 126 | 35 and worse than nastran. |
|
l**o
发帖数: 1240 | 36 跟aviation沾边的东西基本都是用patran,nastran，在学校和一般的公司很难接触到
而且什么那些FAA的regulation和standard没工作经验的人根本没概念
进这行也不容易啊
.. |
|
r********o
发帖数: 1423 | 37 各个学校不一样，偶读书的时候学校里面patran/nastran的license有100个，至于ansys/
proE这些每台computer lab里面的pc都有，全部公用。 |
|
r********o
发帖数: 1423 | 38 I believe the reason why nastran is standardized is simply because it's
introduced by NASA, and the NASA outourced the code to other company like MSC
and Nei, they introduced their pre-processing soft, like patran/femap...etc,
hehe
widely |
|
l**o
发帖数: 1240 | 39 Nastran is the only FAA certified FEA software
there should be something special about it
MSC |
|
r********o
发帖数: 1423 | 40 Thanks for your reply, it's very helpful. I did run several additional simple
models with in-plane torsion of plate element and laminate element with same
isotropic material on each layer with CQUAD4 and CQUADR individually, the
results are the same. But it seems the CQUADR doesn't support the laminate
element, though the displacement I got is the same with the CQUADR plate
element, no data available for the laminate layers. |
|
p**e
发帖数: 126 | 41 Eif you use anisotropic material, might see the difference. for isotropic
material layers do not make any difference as the result would be the same
if you integrate over three points across the thickness or three points in
each layer. however, if the layers are not isotropic material, then the diff
might surface. i suspect the 6 dof element did not implement the laminate
theory. Natran is a nasty old car, patched here and there so it can tumble
ahead, eventually, it is going to break down unles |
|
r********o
发帖数: 1423 | 42 这个单元大家一般都是什么时候用? 俺觉得没什么机会碰到用这个单元，除了在hybrid
mesh的时候用来连不同类型的单元。
这个element的原理俺基本了解，相当于一个force link，但是在工程运用上俺见到用
过的机率不多。rbe3基本上相当于分力的一个单元，本身不具备任何stiffness，和
rbe2刚好相反。但是在工程上传力的组件基本上刚度都比较大，而且一般比构件的其他
部位刚度大，所以俺觉得用rbe2在大部分情况都应该可以。比如说一个steel的bolt穿
过一个alum的lug，这种时候俺也认为用rbe2更好，大家以为呢? |
|
z*****y
发帖数: 163 | 43 如果往analysis发展，多熟悉一些比较常用的fea/cfd软件，比如ansys,nastran,
fluent等，以后找工作没坏处 |
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s*****r
发帖数: 261 | 44 就想了解下，目前在实验室和工业界做project，哪个工具应用面广些：
1. ANSYS
2. COMSOL
3. ABAQUS
4. MSC/patran or nastran
5. ALGOR
6. ADINA
7. CFD-ACE+
8. FLUENT
9. CFX
后三个是流体方面的
帮忙顶一个，谢谢大家 |
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r********o
发帖数: 1423 | 45 you don't even list Nastran/Patran, hehe |
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a******n
发帖数: 98 | 46 Already solved my problem: there is a command of "inertia relief" in both of
ANSYS and Nastran. |
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u****d
发帖数: 122 | 47 How do you think the other two mostly used FEA softwares, Nastran and Abaqus?
widely
direct solver is needed to solve the problem), but not robust when it comes
to highly nonlinear problems (geometric and material nonlinearities, contact
, etc.), often diverging when involving iterative procedures. Tentalizing
with the parameters to get a successful run often takes quite a long time. I
personally never used Ansys before, but I saw a former colleague of mine (
who then had muitiple-year experien |
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l***o
发帖数: 7937 | 48 Nastran is mostly used aerospace and defense industry. Strong linear static
function, efficient and accurate solver, strong frequency and modal analysis
(vibration decomposition and combination) and buckling mode analysis
functions. Not strong for highly nonlinear analysis in time domain. There is
no advanced material models and functionalities like fluid-structure
interaction, very weak contact function (gap element may serve so, but far
from meeting users' need).
I did not use Abaqus before. |
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l***o
发帖数: 7937 | 49 (1) 你说的这些现象都与雷诺数很大(强对流)的流体有关(thermodynamics, acoustics
, 高频电磁场也可归为流体)，所以猜想你在说CFD。CFD主要解决流体问题，但对固体
问题就有其局限。不管设计飞机还是设计汽车，CFD的应用实际是很窄的。95%的设计都
是由有限元软件完成的。CFD也就是在AC设计和噪声(acoustic)设计时用一下。事实就
是如此。你说的这些现象，实际上很多有限元软件也能得到acceptable的结果。
(2) 你说的这些现象，目前都是研究的难题。估计目前还没有软件能够算的很好(有错
误请指正)，即使是CFD软件。
(3) 根据离散方法的不同，有所谓的有限元法(FEM)，有限差分法(FDM)，有限体积
法(FVM)，边界元法(BEM)，High-Resolution Schemes。这些方法各有利弊，应用于固
体力学、流体力学、断裂力学、表面力学、声学等等。
(4) 不管你是否愿意，NASTRAN，LS-DYNA，ANSYS，ABAQUS，ADINA等，都统称商业
有限元软件(commercial finite element softwa |
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l***o
发帖数: 7937 | 50 Does this package assume crack develops in a predetermined direction, as
is often the case for the debonding, decohesion or delamination of laminates, using CZM and cohesive models, or is it moderately general like the crack-tip element in NASTRAN and ANSYS, or even more general like FRAC3D?
What is the output of the package? Is it given as the history of crack size, or is it given as the history of damage index as in CDM, or is it given as the number of cycles as many fatigue software packages |
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