Rice University Mechanical Engineers have developed a polymer based material that becomes stiffer when subjected to repeated stresses. Normally materials tend to break down under repeated stress.
After two weeks of compressions, the stiffness increased by 12 percent. The material is a composite created by “infiltrating a forest of vertically aligned, multiwalled nanotubes with polydimethylsiloxane (PDMS), an inert, rubbery polymer.”
Professor Carey said one of his biggest challenges was programming his computers and measuring instruments into believing the sample could actually get stiffer as it was not part of their programming.