Impact
ASME B31.3 Stress Range Factor: The 2022 Revision and Why It Matters
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
Wind Turbine Blade Number Trade-offs
Introduction Nearly every utility-scale wind turbine built today has three blades. This was not inevitable. One-blade and two-blade machines were built and fielded in the 1980s and 1990s, and multi-blade rotors dominated the farm windmill era for a century. The three-blade configuration won a genuine… Read more
Ryanair 1879: Engine Failure, Window Loss & Partial Passenger Ejection
Ryanair FR1879 — Fault Tree Analysis | VibrationData VIBRATIONDATA · INCIDENT ANALYSIS T. IRVINE · 11 JUL 2026 A fault tree for the July 10 uncontained engine failure over North Macedonia — and why one seatbelt turned a repeat of Southwest 1380 into an injury… Read more
The Convair Sea Dart: Hydro-Ski Vibration & Fatal Dynamic Overload
Introduction The Convair F2Y Sea Dart was one of the boldest experiments of the early jet age: a delta-wing, supersonic seaplane fighter that took off and landed on retractable hydro-skis in San Diego Bay. It remains the only seaplane ever to exceed the speed of… Read more
Composite Material Coatings
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
High Frequency Mechanical Impact (HFMI) Treatment for Weld Fatigue Improvement
Image https://empowering-technologies.com/metal-improvement/ultrasonic-impact-treatment/process/: Introduction Welded joints are the fatigue-critical details in most steel structures. The weld toe combines a sharp geometric stress concentration, tensile residual stresses approaching yield, and microscopic slag intrusions that act as pre-existing cracks. As a result, the fatigue strength of an as-welded… Read more
Surface Ship Shock, SRS, DDAM, MIL-DTL-901, UNDEX
The image shows a MIL-S-901D Barge Test. A reader recently wrote in with two requests: (1) blog posts on surface ship shock and shock response spectra derived from acceleration data, and (2) coverage of underwater explosion (UNDEX) shock effects on submerged components such as batteries.… Read more
Stop Drilling for Fatigue Crack Arrest
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
Strain Rate Effects: Why Metals Get Stronger but Less Ductile Under Dynamic Loading
Strain Rate Effects: Why Metals Get Stronger but Less Ductile Under Dynamic Loading Introduction A common observation in shock, impact, and ballistic engineering is that metals behave differently under dynamic loading than they do under slow, quasi-static loading. A structural steel or aluminum alloy that… Read more