industry

I have been asked to give more details on Dr Cloutier's contribution to the field of overhead electrical conductors (power transmission lines) mechanics. I just received the attached document, written by one close colleague of his, Dr. Claude Hardy, who retired from IREQ, Hydro-Quebec research branch. A nice tribute to Louis Cloutier's legacy.

Mechanicians interested in interdisciplinary research on composites for photovoltaic energy applications, please download the free reports for policy makers and photovoltaic companies published by the Task 13 of the International Energy Agency: 

http://mailchi.mp/c40cfc488823/iea-pvps-newsletter-pv-power-update-39?e=...

The ERC Starting Grant CA2PVM is glad to have contributed to this outreach activity, see:

My friend and former colleague, Dr. Louis Cloutier, passed away on February 26. A long time Hydro-Quebec engineer, among other achievements, he will be remembered for his major contribution to the solution of electric power transmission mechanical problems, most notably to Aeolian vibration control, and related conductor fatigue.

A new paper by Chen et al.: Experimental research on bending performance of structural cable. In: Construction and Building Materials, 15 October 2015, Vol. 96, pp. 279-288. Equivalent bending stiffness has been obtained applying a force at midspan of simply supported, about one meter long, specimens. A number of tensile force levels have been applied (including zero). Non-linear force-deflection curves are shown.

I´m doing a plastic collapse evaluation as per API 579-1 Appendix B1, and one of the load cases is Earthquake loads. 579 refers to ASCE 7, which for tanks refers to API 650 Appendix E. The approach in 650 is a static equivalent lateral force seismic analysis where you find equivalent lateral forces and moments according to some likely earthquake spectrum. It seems that what you do is apply these at the top of the tank shell, which mimics the overturning and shear behavior, assuming the tank doesnt slide from inertia. 

Hello everybody,

Single strand cable bending, stick-slip, analytical models require that a choice be made between two contact modes between adjacent wires: either radial (between layers) or lateral (between same layer wires). In most recent models (e.g. Papailiou’s) radial contact is selected. A “lateral contact” model has been presented by Panetti in 1944 and can be found in the proceedings of the Turin Royal Academy of Science. A translated version from Italian is proposed in the attached file.

With the availability of different brands and grades of cables in the market, it can be pretty challenging to narrow down the options to a few good ones. As with several other things related to wires, a high price tag or big brand name doesn’t actually help in making the right selection. Instead, one has to look out for particular characteristics and specifications for picking the right cable.

Some 2014 papers on the mechanics of helical strands: cables and electrical conductors

A 2014 paper on cable FEA modelling

One approach to helical strand (cable or overhead electrical conductor) bending analysis puts the emphasis on friction rather than on elastic curved rod behavior. Based on Coulomb’s laws of friction, it leads to stick-slip models where strand  bending stiffness varies with imposed curvature (Papailiou, 1995). Such an approach can be traced back to a Ph.D. thesis by H. Ernst, in 1933. This work is in fact often referred to in cable analysis reports. An English translation (with a short presentation) of the dissertation analytical part is attached.

Several approaches have been used to deal with the complex problem of helical strands in bending. One of them is based on Love’s curved rods theory. It has first been used by Costello in his classical monograph “Theory of Wire Rope”. It has been extended by Sathikh et al. in several papers. A new contribution from this group is a Ph.D. Thesis by D. Gopinath : “Some studies on bending response of the stranded cable under free bending and constrained bending”, Anna University, Chennai (India), October 2013, 121 pages.