opinion

Jian-zhong Zhao's picture

Inconsistency of Biography of Tsien Hsue-Shen

Tsien Hsue-Shen, an expert of mechanics, the “King of Rocketry” of China, lived in US for twenty years long. Iris Chang (by a book in 1995) and Judith R. Goodstein (by a report of a conversation with Lee Alvin DuBridge in 2003) gave accounts of Tsien’s biography. In 2013, “Exhibition of Achievements of People’s Scientist Tsien Hsue-Shen” toured to universities in Shanghai and Chinese cities of Beijing, Kunming, Chengdu, Wuhan, Lanzhou and Huhehaote, displaying a different version of Tsien’s activities in US and declaring that Tsien read and studied, with great concentration, the philosophy of Marxism during his stay in US.


Pressure vessel deflection

Hi,

 

I have observed in many cases that horizontal pressure vessel with saddle support due to the internal pressure gets circumferentially compressed (vertical deflection).

Can anyone expalin why it behaves so.

Regards,


Plastic J significance in CTOD equation

I am working on the validation of CTOD.


Gareth Forbes's picture

Publication citation metrics and h-index for Australian Universities


For similar reasons outlined by Zhigang’s post http://imechanica.org/node/2345 I
have found it necessary to find comparisons in publication citation
metrics/indices whilst in Academic employment. Much has been discussed about
the appropriate use of these metrics and the arguments on the benefits and
drawbacks are both compelling. Whatever your opinion, it seems that for the
foreseeable future these publication citation metrics are here to stay.


Time's picture

2014.02.26

A new beginning of learning! 

Be tranquille, and just do it.

 ——Time


Modelling tensile simulation including necking

HI,

 i am new in using ABAQUS. I am modelling tensile simulation. elastic and plastic part were ok (isotropic). but i dont know how to include damage model (damage for ductile materials). I need stress triaxilaity, equav plastic strain and strain rate..where i can obtain that?..hope somebody can help.  Material used is ALSi12


Mechanics journal impact factors 2012

Some funding agencies require that articles be published only in journals with impact factors greater than 1. Here's a list from 2012 that tells you which to choose (if you care about impact factors).
-- Biswajit

 


health and safety environmental management

 

Dear all  

i have question that i woud like to know about principle of putting monetary value on human to rduce risk and the principle of weighting the importance of risk , moreover is there any conflic between these principle  

 regards  


Solid Mechanics mini project

Guys , we've been given a mini project of solid mechanics to make any simple model which shows movement . We're getting short of time so please .... Frown
I'm looking for some ideas of how and what to make .


Solid Mechanics mini project

Guys , we've been given a mini project of solid mechanics to make any simple model which shows movement . We're getting short of time so please .... Frown
I'm looking for some ideas of how and what to make .


zaphai's picture

Soil Structure Interaction

I am trying to model the soil churning action of a rotary tiller trough soil structure interaction. Based on some published articles, DEM and SPH approach both have been used to model the tool interaction with the soil. I am little confused in the selection of the appraoch. Can somebody throw some light on advantages and disadvantages of one approach over another and which approach should be chosen for more realistic results.


Hyperelastic and Viscoelastic material modelling

I have a doubt regarding the Hyperelastic and Viscoelastic material modelling in ANSYS using Mooney-Rivlin material constants.

ANSYS theory manual says that for large deformation and large strains, the material modelling (i.e. constitutive behaviour) is same for hyperelastic and viscoelastic. Is it so?

Generally,  Mooney-Rivlin material constants are used to model Hyperelastic behaviour (rubber-like materials).

But can I use Mooney-Rivlin material constants, which we get from curve fitting the test data, to also model a  viscoelastic material which has large deformation and large strain (10-20%)?


A question on plasticity

Recently, I have a question on the plasticity.As the plastic materials undergo the loading and unloading process. we can find the energy dissipation from the stress and strain relation curve. Then, my question is that the energy dissipation is generated during the loading process or unloading process?Thank you very much.

 


Konstantin Volokh's picture

Challenge of Biomechanics


The application of mechanics to biology
– biomechanics – bears great challenges due to the intricacy of living things.
Their dynamism, along with the complexity of their mechanical response (which
in itself involves complex chemical, electrical, and thermal phenomena) makes
it very difficult to correlate empirical data with theoretical models. This
difficulty elevates the importance of useful biomechanical theories compared to
other fields of engineering. Despite inherent imperfections of all theories, a


Mikael Öhman's picture

What are my Open-Access options?

As many othes, I find myself in the position that my funding agency mandates some form of parallel publishing (or preferably OpenAccess) (as well as an Open Access policy from my university itself).

I've been reading through what author rights i retain with different publishers, and among the big ones very little rights are retained.
Elsevier allows preprints to be published only if it is voluntary. That is, they intentionally prohibit mandated parallel publishing to protect their profit.
Wiley had different rights with different journals, but my first hand choice simply didn't allow parallel publishing of any kind ever.


John E. Dolbow's picture

Guidelines for Suggesting Peer Reviewers for Manuscripts

As a journal editor, I am often surprised by some of the suggestions authors make for potential reviewers.  In some cases the suggestions are not very good, and on occasion authors do not suggest reviewers at all.  Some authors will even state explicitly that they cannot think of any reviewers, which is really surprising.   


Hooke's law

Upto what limit is hooke's law really obeyed ? some books say that hooke's law is obeyed up to the proportional limit, while some other books say that hooke's law is upto the elastic limit ? what is the correct answer?


Guanchu Cheng's picture

thermodynamics equilibrium state vs. steady state???

I am not clear about two concepts: thermodynamics equilibrium state and steady state. It's easy to conceive of the following different two osmosis processes regarding thermodynamics equilibrium state and steady state, respecitvely.


FEM analysis of composite plate in ANSYS

HI..

i am doing FEM analysis of composite plate[0/+45/-45/90]S in ANSYS. I just wanna now which material properties i have to give as input, lamina properties or laminate plate properties..??

waiting 4 an early response..

Regards

FURQAN


ahmadmec68's picture

thesis

hi everyone ,

im finding  the subject of my thesis(in master science) i will be glad if anyone offer me the subject with satisfactory future , my tendency is applyed mechanic in stress !

please explain about the future job,

thank you 


yosoufe's picture

Smart Headphone

Hi

I am thinking of a SMART HEADPHONE for people who are listenning to the music all the time for their saftey an their convenience and the people who tries to communicate with them. How SMART? The danger for such people is that they can not hear the alarm of the danger, like the horn of a vehicle. And also, sometimes they are called but they do not hear and consequently they do not show any reaction. This is so bothering for other people.

The tech: 


Liang Xue's picture

What a shame

What a shame

help each other to solve our problems

Hi dear mechanicinas

we are here to help each other solve our problems.agree?

so why don' read others blogs?

I have written several blogs till now.but just afew people read them and just no one answer!

the  last one was"why I can't define composite layup in abaqus explicite"the error is parameter composite can not be used in abaqus explicit!

thanks

BEST REGARDS


Lin.Zhang's picture

what the strain gauge rosette measures is in status of plane strain or plane stress?

I read some textbooks about mechanics of material. regarding strain measurement with strain gauge rosette, most of them regard it as  in the plain strain status.  But in my opinion, what the strain gauge rosette located is a fress surface. In this way, the thress stress components related to this plane, that is zz, zx, zy, should be zero, assuming that  the out normal of this plane is in the direction of Z axis.  then there are sigmaxx, sigma xy, sigmayy to be measured.  Is there anything wrong with my understanding? 

 Thanks in advance. 


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