Need some help with ROPS analysis and design Criteria  

    I am aware that the (Roll Over Protection Structure) ROPS analysis is an ocean and I have just started to explore it as there is a need of it at my work. As of now, I have more questions and many wrong answers. So kindly bare with me. I will start with a brief introduction of what I know followed  by my question.

I am currently working on deriving equations for different vehicle models using Lagrangian and Newtonian methods. I am need of parameters to test few MATLAB models, and in vague to know exactly how to classify the mass into sprung and unsprung. Similarly, how do I obtain the MOI separately for the unsprung mass?

Dear all

I want to start modeling the Hyper foam behavior in abaqus software, it is very usefull for me to consult with someone who works on that.

Regards

Babak

Tribology is defined as the science and technology of interacting surfaces in relative motion, which involves friction, wear and lubrication.

The term “tribology” was introduced in the 1960s by Prof. Peter Jost.  In the consequent decades, various aspects of interacting surfaces in relative motion have been the focus of tribology, including, for example, the tribology of automotive applications, microelectromechanical systems, magnetic storage devices, adhesive contact, micro/nanotribology, biotribology.

How many iMechanica users are on Twitter?  And how many are on Twitter with professional contacts? 

 I started to use Twitter about 4 months ago in a completely social, non-professional context.  As a personal (expat-focussed) blogger, I started to notice that I was
catching blog posts in my Twitter feed before I would see them in my
feed aggregator (Bloglines).   Twitter has emerged as a different sort
of feed aggregator, as well as a provider of information. 

Thermal stress does not develop when the free displacement is not constrained. How is this related to the term self equilibrating?

Say, I have a plate with the upper and lower surfaces at two different temperatures. The plate is not having any other constraint to prevent themal expansion. Why thermal stresses will not be generated in this case ( because of temperature gradient)?

Regards

Hello,

Recently I faced few questions in a course that I am attending:

1) Outline the salient features of different higher order shell theories.

2)Explain why some shell theories are not suitable as the basis of element formulation.

3) Discuss any limitations of elements being used in relation to their underlying formulation ( e.g use of shallow shell theory or cylindrical shell theory).

Hello 

what do think why investigators await about 3 decades to calculation of local stress/strain by elastic-plastic fracture mechanics?and basically why elber's discovery[crack closure] was so important and play a key role in numerous articles?

How can i calcualtion the amount of load transfer through the contacting crack faces?

How can i determine the location of it?

Thank you

Hadi

I would like to know why ABAQUS is the dominant FEM program (in terms of comments) in this forum? Why do you consider ABAQUS over ANSYS?

I have been using ANSYS for at least 8 years and I am very please with the capabilities of it. But I have not seen ABAQUS or used it. Beside, reading all the comments that are posted in imechanica, I feel like I am using the wrong FEM program. 

Which are the advantage of ABAQUS over ANSYS?

Thank you,

 Mario J . Juha

www.eng.usf.edu/~mjuha/

Many of us (including myself) have used the nonlinear equations for elastic plates, originally proposed by von Karman (1910). I recently came across a book with some interesting comments about the plate equations, which may be of interest to share with others on imechanica. The book's title is "Plates and Junctions in Elastic Multi-Structures", authored by Philippe G. Ciarlet and published by Springer-Verlag in 1990.

The
ed hardy Clothing was getting out to everyone and I noticed, in certain areas, that people were really into this shit. I thought it was a little weird mostly. Why? Because its based on a tattoo artist by the name of Don Ed Hardy. Christian Audigier was pretty much making shirts based of his tattoos. I admit, I do like Don Ed Hardy’s tattoos on people but not on clothes. Don’t get it twisted. I found the tattoo concept interesting. But it only appeals to me it as a coloring book on a shirt.

In my opioion, the traditional concrete model is taking the smeared cracking concept to deal with the tensile cracking and using the elastoplastic method to deal with the compressive softening.

We can find that recently the CDM based concrete model become a hot research subject.

But what are the advantages of the CDM-based?

Thank you very much!

sir ,i ahve some problems in use ansys element CERIG,MPC 184 and RB3 elements....what is difference in transfering loads to slave nodes using MPC184 elements and command CERIG and RBE3 ..

and also why mass21 elements are required if u defining coonection usimg CERIg and RBE3 command..

plz...advice and clarify my doubts to understand better..

thanks and regards..

-dileep 

From PhDComics via Entertaining Research :

Hi dear

I am going to model a bridge in dental work which it consists of two parts:

1: a small beam which it is made of composite 5 plys

2: a cramic part which surround the beam.

I want to model it with Abaqus. Please help me if you can. I'd appreciate if you help me and send its steps to my email: kian32m@yahoo.com

Check out the talk by Dr. Arden L. Bement, Jr., Director , National Science Foundation 
on TAM 

at  http://www.nsf.gov/news/speeches/bement/09/alb090424_tamsymp.jsp?govDel=USNSF_51

For the proceedings of the 2008 SBE&S workshop go to

 http://www.wtec.org/sbes/workshop/FinalWS-20080425/SBES-allpresentations-30Apr08-lowres.pdf

Obama spoke at the National Academy of Sciences on Apr. 27, 2009, in which he states his commitment to doubling of science funding and stem education. From his speech,

 "At such a difficult moment, there are those who say we cannot afford to invest in science, that support for research is somehow a luxury at moments defined by necessities.  I fundamentally disagree.  Science is more essential for our prosperity, our security, our health, our environment and our quality of life than it has ever been before."

You may also find a recent pertinent discussion in iMechanica interesting.

 A video of Obama speech follows.

I’m at a meeting in DC.  The speaker now is Henry Petroski.  The theme of his lecture is on the different roles of science and engineering.  Here is the opening paragraph of his piece in The Washington Post early this year. 

"We will restore science to its rightful place," President Obama declared in his inaugural address. That certainly sounds like a worthy goal. But frankly, it has me worried. If we want to "harness the sun and the winds and the soil to fuel our cars and run our factories," as Obama has decreed, we shouldn't look to science. What we need is engineering.”

A few of us have been discussing/debating over the existence or non-existence of Cauchy stress questioned in a theory proposed by Mr. Falk H. Koenemann. While such discussions may appear funny or irrelevant to many mechanicians, I take it as a challenge from an educational point of view to clearly understand what continuum mechanics is about and if any what are its limitations. Unfortunately, the discussions have not been fruitful and probably have become annoying to many who read imechanica. For that I apologize from my part. However, I remain hopeful that some consensus may be reached, if we can clear out or admit the misconceptions that have been brought up in the discussions from both sides. To begin with, I summarize below in a list of possible misconceptions about a point in a continuum and a particle in a discrete system. It is my understanding that the two are fundamentally different but have been mixed up in Mr. Koenemann's theory as well as in the discussions. As many mechanicians are doing research in both continuum mechanics and discrete modeling (e.g., atomistic, molecular dynamics), such a list may not be totally irrelevant. Of course I would welcome comments and discussions to make the list more accurate and more complete.

The day before yesterday, Mar. 14 (3.14), was a great date, because Albert Einstein was born at the same day 130 years ago.

I and my wife enjoyed a very good holiday that day in Taipei. Most interestingly, we found a vivid statue of Einstein made by Ju Ming, stood still in front of the Chen-Ping (eslite) bookstore.

We took several photos around this statue. Here I share one of them with you.

An ice block submerged in the water, if the ice melts level of water Whatwill be the level of water .

1. Increase

2. Remain Same

3. Decrease

Now I come here again.

From now on I want to share with you my research experiences and personal opinion on  time dependent quantum system, photonic/sonic crystals, and metamaterials.  I would also like to write some articles on science teaching stuff.

I come from Taiwan. Usually I speak chinese, and have no many oppernituties to practice my English, so I wish someone can help me to improve my English. Thanks !

From PhDcomics

Micromechanics---loosely speaking, is the study of heterogeneities in materials and its consequences for material or continuum behavior. This encompasses studies of inclusions, dislocations, cracks or more generally defects. A related problem is that of "coarse-graining" or in other words the effective homogenized properties of a heterogeneous material. The latter is a recurring theme in all of physical sciences not just solid mechanics. Micromechanics, a formidable subject by all means, dominated a substantial part of the history of solid mechanics. Several of our Timoshenko awardees have been associated with this subject, e.g. Eshelby, Hill, Keller, Irwin, Rice among others.