Originally Posted by Abhijit67

Dear experts,

With reference to published papers by some chinese as well as polish academicians, it is observed that they have carried out Dynamic Analysis using AMEsim Software and claiming that their results are almost similar to the results obtained by professional Dynamic Analysis Softwares for Trough Belt Conveyors (only).

What is the opinion of the experts in this regard...

------------------------------------------------------------------------------------------

This is a one dimensional model. Any good dynamic analysis is either 2 or 3 dimensions. By example, the belt has a longitudinal(belt long axis) and vertical (sag between idlers) response. This becomes pronounced with belt tensions that create reasonable sag below 1%. This condition can be very localized or it can be spread over a substantial length of the conveyor, usually during stopping. The counterweight (assuming GTU) will travel up and release a large amount of belt feeding the low tension zone.

IF the model cannot follow this condition, I claim it can be dangerous when conveyor geometry is sensitive to high localized sag. Some reputed software cannot follow this condition. Remember the Arab Proverb - if you know not and don't know you know not - you should be ignored/shunned ■

I have not seen any publications on this software. Can you reference the publications?

How can this software set the boundary conditions and follow behavior such as moving mass, all things sensitive to belt tension, any drag that is velocity sensitive, et al.?

Maybe a publication will clarify these and other points. Note: the solution is very non-linear and cannot be solved with ODE's. Early published attempts, show the weakness and errors.

CDI has many hundreds of conveyor designs showing the need for at minimum a 2-D model that uses time integration and forward predictor model.

Professors Gabriel Lodewijks of Delft Univ. and Craig Wheeler, Newcastle Univ. have published on this. Professor Zur, a Polish professor, showed how his associates had also created a rheological and 2-D version that he claimed preceded the Conveyor Dynamics, Inc. (CDI) BELTFLEX model.

The solution requires solving the time integration of a hyperbolic function (sag), which is not trivial.

There are other hidden physics, which should be addressed. ■

With due respect to Mr. Lawrence Nordel for his legendary contribution in conveyor engineering field, nowadays his comments are driven mainly from his own commercial interest. This, in fact, removes the shine of many academic discussions and diffuses the enthusiasm the discussions could have created.

Yes it is known that two dimensional analysis would give better result than one dimensional. The second dimensional issue, that is the effect of sag between idlers, can be reflected in spring constant and damping constants at each location, which will depend on many parameters like local tension, belt/material weight, elastic modulus, idler spacing etc. There are established and published relationship to get such values of spring and damping constants at each location, which will vary with time since the tension varies with time during starting and stopping at each location. Hence, if AMESIM software can be tuned to use such variable spring and damping constants at different locations at different times, then 2 dimensional analysis can be performed. Least but not the last is that differential equations are to be solved in all circumstances, which AMESIM can do without much code writing. So I see lot of possibilities in using AMESIM, which is otherwise a very reputed simulation software, for conveyor dynamic analysis. ■

Originally Posted by ambhad

With due respect to Mr. Lawrence Nordel for his legendary contribution in conveyor engineering field, nowadays his comments are driven mainly from his own commercial interest. This, in fact, removes the shine of many academic discussions and diffuses the enthusiasm the discussions could have created.

Yes it is known that two dimensional analysis would give better result than one dimensional. The second dimensional issue, that is the effect of sag between idlers, can be reflected in spring constant and damping constants at each location, which will depend on many parameters like local tension, belt/material weight, elastic modulus, idler spacing etc. There are established and published relationship to get such values of spring and damping constants at each location, which will vary with time since the tension varies with time during starting and stopping at each location. Hence, if AMESIM software can be tuned to use such variable spring and damping constants at different locations at different times, then 2 dimensional analysis can be performed. Least but not the last is that differential equations are to be solved in all circumstances, which AMESIM can do without much code writing. So I see lot of possibilities in using AMESIM, which is otherwise a very reputed simulation software, for conveyor dynamic analysis.

-----------------------------------------------------------------

Ok, a concession to 2-D Dynamic Analysis is good. 2-D analysis necessities was published 30 years ago, in 1984. Thirty years is ample time for ISO 9000 like-and-kind to embrace it. If your point is to accept it as better, then why the criticism of the technique? Tune away your day my friend and publish the tuning for others to practice, once you have validated it over the range of operation conditions or noted the potential for errors. Watch out for that excessive counterweight travel, belt curvature motion, spillage, and defeated control functions.

What commercial interest, since I am in retirement? I leave detail engineering to more capable hands within CDI. Don't you agree a dull penny, without shine, still has value? I leave the measured value/shine of such discussions to those that may benefit from known historical facts or analytic insight. Engineering is fun and can be rewarding in ways that cannot be measured by money. Anyone who has enjoyed solving a challenging puzzle knows that.

Seems you are trying to convince others in the ability for 1-D Conveyor Dynamic Analysis to satisfy good design practice. Since most Dynamic Analysis practiced is by 1-D, you are in the majority. There are many which accept shoddy work that passes for proper engineering. Often such practice is acceptable, since the design did not fail. Did the machines life get compromised? Could the design function be improved or its risk lowered? If you "know not", per the Arab proverb, and are willing to accept such risk, then I say the client should be aware of your intentions. Usually, failed practices are not published due to embarrassment of Clients and their Consultants. I note you are a Consultant. ■

Originally Posted by nordell

-----------------------------------------------------------------

Ok, a concession to 2-D Dynamic Analysis is good. 2-D analysis necessities was published 30 years ago, in 1984. Thirty years is ample time for ISO 9000 like-and-kind to embrace it. If your point is to accept it as better, then why the criticism of the technique? Tune away your day my friend and publish the tuning for others to practice, once you have validated it over the range of operation conditions or noted the potential for errors. Watch out for that excessive counterweight travel, belt curvature motion, spillage, and defeated control functions.

What commercial interest, since I am in retirement? I leave detail engineering to more capable hands within CDI. Don't you agree a dull penny, without shine, still has value? I leave the measured value/shine of such discussions to those that may benefit from known historical facts or analytic insight. Engineering is fun and can be rewarding in ways that cannot be measured by money. Anyone who has enjoyed solving a challenging puzzle knows that.

Seems you are trying to convince others in the ability for 1-D Conveyor Dynamic Analysis to satisfy good design practice. Since most Dynamic Analysis practiced is by 1-D, you are in the majority. There are many which accept shoddy work that passes for proper engineering. Often such practice is acceptable, since the design did not fail. Did the machines life get compromised? Could the design function be improved or its risk lowered? If you "know not", per the Arab proverb, and are willing to accept such risk, then I say the client should be aware of your intentions. Usually, failed practices are not published due to embarrassment of Clients and their Consultants. I note you are a Consultant.

This time Nordel you have become more sentimental than logical. I have no intention of going into an altercation with a towering personality like you. I am also a retired engineer of age more than 60 and have spent many years with consultants and as well as contractors. If you believe, I declare that I have no intention of pushing 1D analysis as you have wrongly understood. There are many papers in the net who has done good work using AMESIM and other standard software, but many of them are not in English. It may be painful for you to accept their merits, but many are doing good job in the field in their own ways. It is the duty of the engineering community to encourage them so that someday this analysis comes out of today's black boxes. The apprehensions you have raised are related to loss of tension at certain zones of belt, specially during stopping and be assured that issue is also being taken care of. So Nordel let us give some space to others who are at least trying to do something seriously. Best regards. ■

Originally Posted by ambhad

This time Nordel you have become more sentimental than logical. I have no intention of going into an altercation with a towering personality like you. I am also a retired engineer of age more than 60 and have spent many years with consultants and as well as contractors. If you believe, I declare that I have no intention of pushing 1D analysis as you have wrongly understood. There are many papers in the net who has done good work using AMESIM and other standard software, but many of them are not in English. It may be painful for you to accept their merits, but many are doing good job in the field in their own ways. It is the duty of the engineering community to encourage them so that someday this analysis comes out of today's black boxes. The apprehensions you have raised are related to loss of tension at certain zones of belt, specially during stopping and be assured that issue is also being taken care of. So Nordel let us give some space to others who are at least trying to do something seriously. Best regards.

------------------------------------------------------------------

The thread starter asked for an opinion about AMESIM. Was the thread starter asking an opinion of lecturing about AMESIM?

My only regret is answering to condescension and negative hyperbole. I hoped we could talk as equals. I am not your beacon, that is clear. Some may wish to know, what lurks behind the obvious - claims of many noted publications about AMESIM on belt conveyor dynamic analysis. Can we see the references? Some of the audience can read graphs and also use Microsoft or Google translators. As we are now communicating in English, we can therefore establish extension of your ideas. AMESIM may be a excellent tool. I as others may wish to use such a tool or at least know of its features. Do not take a question as a putdown. Please take enquiry on face value.

----============================================================= ■