A slender store hanging under a fighter wing sits in an acoustic field near 164 dB overall. A wind chime tube hanging from a porch beam sits in an acoustic field near 40 dB. The store is asked to survive; the chime is asked to… Read more
Image credit: Merchant Navy Decoded — Propeller of Ship Walk along any harbor dry dock and you will notice that ship propellers almost always have between three and six blades, with four and five being the most common for merchant vessels. The blade count is… Read more
VibrationData · Aviation HistoryT. Irvine · 11 Jul 1926 + 100 The “Tin Goose” convinced America that flying was safe. Nobody said anything about comfortable — a case study in excitation, transmission, and radiation. TypeFord 5-AT Engines3 × P&W Wasp R-1340, 420 hp DriveDirect —… Read more
The carbon fiber automotive part in the photo above shows two composite engineering choices worth examining before it ever sees the road: the woven fabric architecture visible through the surface, and the glossy clear coat protecting it. Composite structures rarely fail in the fiber direction… Read more
Introduction Uniaxial fatigue methods, whether stress-life, strain-life, or spectral, presume that a single stress or strain component tells the whole damage story. Real hardware disagrees. Shafts carry bending plus torsion, pressure vessel nozzles see biaxial membrane stress plus thermal bending, and vibrating structures respond in… Read more
Image credit: Nikhil Patil Introduction Most vibration-induced fatigue problems in aerospace and industrial structures live comfortably in the high cycle fatigue (HCF) regime, where nominal stresses remain below yield and the stress-life (S-N) method with rainflow cycle counting serves well. But some of the most… Read more
Image credit: https://www.sintechnology.com/portfolio-articoli/hole-drilling/ Drilling a hole into a structure is normally something an engineer tries to avoid — holes are stress concentrators, fatigue initiation sites, and sources of structural weakness. But in one important application, drilling a small hole is precisely how engineers measure the… Read more
One of the most counterintuitive repair techniques in structural engineering is also one of the oldest: to stop a fatigue crack from growing, you drill a hole at its tip. Adding material loss to an already cracked structure seems like exactly the wrong prescription —… 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
A reader who leads Product Development for an aeronautical supplier of cabin electronics — seat power systems and security cameras — asked whether VibrationData covers electromagnetic emission and thermal management, particularly for engineers who are not strong on the simulation side. This post is written… Read more