Roberto Ballarini's blog

A few days ago I had a good discussion with a dear colleague on the topic of the current state of scholarship in mechanics and the education of the new generation of mechanicians. During the past few decades most mechanics researchers have limited their activities to the writing of papers and research proposals. This because the “reward system” places little value to the authoring of monographs and textbooks. In fact the number of quality books produced during this period pales in comparison to those written by the giants of mechanics, including Timoshenko, Truesdall, etc.

Two faculty positions are available in the Department of Civil and Environmental Engineering at University of Houston. One is in the general area of geoengineering (including geomechanics), and the other in the general area of fluid mechanics. Additional information is included in the attached advertisements.

I wrote this report a while back, and a limited printing was circulated by Wright Pattterson Air Force Base. I found a scanned version that I attach for your interest.

I have always, and I believe correctly, considered cohesize/bridging models linear elasticity. This is because whether we apply them to holes or cracks, we are solving the equations of ELASTICITY, with nonlinear boundary conditions along the part(s) of the crack along which a traction-separation law is applied. So the material model is totally elastic. All we did was to augment the elasticity theory with an ad hoc physical condition (inspired by experiments such as Dugdale).

University of Minnesota Civil Engineering Faculty Search

I attach an essay we wrote for a book that will be published by University of Minnesota Press titled "The city, the river, the bridge." The essay is a transcription of part of a public lecture I gave on infrastructure and on the bridge collapse.

After the bridge collapse there were several posts on Imechanica that included speculation about the cause of the collapse, including fatigue crack growth, lack of redundancy, etc.. Our investigation determined the collapse was a result of an undersized gusset plate that reached its plastic limit load.