NAS319B - Fatigue & Dynamics - The Reliability of Vibrating Systems

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A state of the art view of fatigue calculations for dynamic systems and vibration environments (such as that defined in military standard MIL-STD-810). This course covers vibration fatigue which brings together structural dynamics, FEA, and fatigue analysis in order to show how systems with dynamic (resonant) response can be assessed for fatigue life. Although MSC products will be used to show example problems the course material will be independent of any software products and generally focused on the technology rather than specific software products.
Length: 
1 day
Pre-requisites : 
The course will give a basic overview of the methods – but from a quite unconventional perspective (concept rather than equation driven). So no prior knowledge of fatigue analysis techniques or dynamics is required. The latest fundamental developments (theories and implementations) in the field will also be presented.
Topics: 
  • Vibration Environments - Random v Deterministic
  • Frequency v Time Domain
  • System Transfer Functions (Frequency Domain)
  • How Transfer Functions Work
  • FFTs and PSDs
  • Calculating PSDs From Time Signals - Buffers and Window Averaging
  • Classifying Time Signals and PSDs
  • Statistics, Probability, and Reliability
  • Loads and “Cross PSDs”
  • Gaussian, Random, and Stationary Data
  • Zero and Peak Crossing Rates, Irregularity Factor, Root Mean Square (RMS) Value & Moments
  • Hand Calculations From a PSD
  • Options For Calculating Fatigue Life From PSDs
  • Vibration Fatigue Solvers - Narrow Band, Wirsching, Steinberg, Dirlik
  • Case Studies Related to Frequency Based Fatigue