\; K_{ISCC} \] where \( \sigma \) is the applied stress, \( a \) is the crack depth, and \( Y \) is a geometry factor. Eyebar 330’s tiny 0.1-inch flaw sat below this threshold for decades, then crossed it after four decades of slow… Read more
By Tom Irvine The spruce soundboard of a concert grand piano and the sheet-steel housing of an industrial gearbox have more in common than their outward appearances suggest. Both are thin panels driven into vibration by an internal source. Both radiate sound into the surrounding… Read more
By Tom Irvine While enjoying a glass of orange juice at an outdoor café in Madeira, Portugal on a sunny Independence Day morning, I noticed the reusable stainless steel straw resting across the glass — its elegant curved bend a perfect reminder that one of… Read more
Photograph taken at a seaside retaining wall in Madeira, Portugal, July 2026. The bolt and nut shown are carbon steel — heavily corroded after prolonged exposure to the Atlantic marine environment.Figure 1. Severely corroded carbon steel bolt and nut at a seaside retaining wall, Madeira,… Read more
VibrationData Blog | Structural Materials If you have ever looked at a stress-strain curve for mild (low-carbon) steel and wondered why it has that distinctive “flat shelf” between the upper and lower yield points, you are not alone. That plateau is one of the most… Read more
PORON® is a commercial polyurethane foam, Rogers Corporation Introduction Microcellular Urethane (MCU) mounts are a highly capable candidate for this application and are widely utilized for military electronics isolation. Several aerospace and defense manufacturers offer products with extensive MIL-STD-810 qualification data and field history in tactical… Read more
San Mateo Bridge, Highrise Section, San Francisco Bay Area UC Berkeley Professor Ed Wilson raised a pointed concern about the Response Spectrum Method (RSM) that structural engineers should take seriously. In his 2015 note, he described the San Mateo Bridge retrofit as a revealing case… Read more
Introduction Neither shock nor vibration response should be used to cover rigid-body acceleration because material limits depend on the strain rate and on the duration of the load. Furthermore, static deflection shapes differ from dynamic mode shapes. Material Stress Limits The following is an excerpt… Read more