A colleague who has started building a simulator wrote in with a short question. He has welded rods in S355 or S420 steel, the welding process is not yet fixed, and he expects that a fatigue assessment will be needed. He has not worked with… Read more
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
A Shell station on a Huntsville, Alabama arterial. Four slender columns, a flat deck roughly 60 feet by 30 feet, fifteen feet of clearance, and a fascia band carrying the brand colors. It is one of the most repeated structural forms in North America, and… Read more
A change to a single equation in ASME B31.3 has meaningful consequences for how piping displacement stress is evaluated in high-cycle service. The change is small in appearance and large in effect, and it is worth understanding both the arithmetic and the seventy years of… Read more
Skyscraper design was once governed almost entirely by strength — could the frame carry gravity, wind and seismic loads with adequate margin? For the new generation of ultra-slender “pencil towers,” the governing requirement has shifted to something more subtle: occupant comfort. A building can be… 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
Image Credit What Solar Trackers Do A solar tracker is a motorized mounting system that rotates photovoltaic (PV) modules to follow the sun across the sky, keeping the panel surface more nearly perpendicular to the incoming sunlight than a fixed-tilt rack can. The payoff is… Read more
Structural Dynamics Series — Detroit Metropolitan Wayne County Airport (DTW), McNamara Terminal, Concourse A DTW McNamara Terminal, Concourse A. The exposed roof structure combines arched panels, downward flying struts, and lateral tie rods. Introduction The McNamara Terminal at Detroit Metropolitan Wayne County Airport opened on… Read more
Fuse Pins: The Structural Fuse That Holds the Engine On Jet engine pylons contain deliberately weakened pins designed to shed the engine under extreme overload — and two Boeing 747 freighter accidents showed what happens when the fuse itself fails from fatigue. An electrical fuse… 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