IDD Method for:

In Bulgarian 

 

This is an (experimental) personal site (under reconstruction and expanding) of Stefan Hristov Stefanov, Ph.D., Bulgarian associate professor: stefanst99@abv.bg, stefanst99@yahoo.com, stefanst@ltu.bg, skype user name stefanst99, phone +++35928697649, mobile +++359885120238

Last changed: 5 June 2009

NEWS 

The method takes the new name IDD ('Integral Method' is still used) under which it was (partly) presented on the Second International Conference on Material and Component Performance under Variable Amplitude Loading, Darmstadt, Germany, March 23 – 26, 2009

IDD will also be presented on the Ninth International Conference on Multiaxial Fatigue & Fracture (ICMFF9), Parma (Italy), 7 -10 June, 2010 (Stefanov is a member of the scientific committee). Maybe you are interested in this conference: please see the website http://www.ICMFF9.unipr.it 

 

The purpose of this site is to popularize and find adherents/ supporters/ followers/ cooperators/ publishers/ sponsors/ employers for:

 

IDD (INTEGRATION OF DAMAGE DIFFERENTIALS) METHOD FOR FATIGUE LIFE PREDICTION UNDER ANY LOADING

 

(under any sort of loading including the most complicated combined, multiaxial, non-proportional, non-cyclic loading with arbitrary or random variations of its stress-time functions)

 

('IDD' gradually substitutes the previous term 'Integral Method')

 

The site contains the WORKING DRAFT of a THESIS being written under the above title. The main feature is that the basic notions are not loading cycle and damage per loading cycle but loading differential and damage differential per loading differential.

 

Most of the fractures of engineering structures are due to fatigue and often cause disasters. How to envisage the time of possible fatigue failure, i.e. how to predict the fatigue life, is one of the most important engineering problems for the last two centuries. There is not any uniform, general and all-acknowledged  method to be universal under any loading: cyclic or non-cyclic, uniaxial or multiaxial, proportional or non-proportional, deterministic or random, covering the general case of multiaxial, non-proportional and non-cyclic loading with arbitrary or random wave-forms of its stress components. This lack of solution is considered as owing to the fact that the fatigue life had not been searched by means of an integral of fatigue damage differentials per loading differentials during time differentials.

 

The thesis opens a new line of scientific research under the above title. The calculus (damage differentials and integral of them) had not been applied before for fatigue damage computing and life prediction. That is why there is not any uniform and general approach to this problem nor is there any solution under arbitrary fatigue loading. Only the universal mathematical way from differentials to an integral can establish such an approach and solution. The new scientific line proposed, if accepted, would re-direct a vast world-wide research experience into another course.

 

Imagine that Newton and Leibniz ask you, “Didn’t you try to describe the fatigue damage accumulation as a process of integrating differential by differential? Still not? But we discovered the differentials and the integral of them, the calculus, for you, and all the other sciences progressed just by using them!”

   

If you are interested, please open (or first save on your computer) the chapters respectively the subchapters of The Thesis published in this site so far. You may also navigate from Dates of (sub)chapters.

 

Preview is easy and even amusing to read. It contains a section titled To the attention of potential users. You could better start with that section. You may continue with Subchapter 1.1, Subchapter 1.2 and so on and meanwhile read Contents, Symbols and References.

 

You may always contact me and give your opinion, remarks, questions, recommendations, willingness for cooperation, requirements in case I should edit my English and explain better on some places, etc. Thus I will be happy and stimulated to continue my work. You may also sponsor and even employ me to continue developing the method for you.

 

If you are not interested, please forward this site to other colleagues of yours who may take some interest. Especially, post-graduate students (doctorands) looking for a subject of their future doctoral studies may be interested. Or, you could assist for providing links from other sites to this site (as I do in return: see the Related Links navigation button).

 

Thank you for reading this.

 

        Stefanov