Engineering Commons^™

Correlation Of And Development Of Procedure To Use A Resonant Plate With Mechanical Excitation For Shock Testing Small-To-Medium Size Spacecraft And Provide Aerospace Shock Analysis And Testing Guidelines, Monty Kennedy

Dissertations, Master's Theses and Master's Reports

In the aerospace industry it is known that performing shock analysis and testing on spacecraft is difficult to do mostly because shock loads create a very short duration shock wave transient that can have high acceleration peak levels (1,000-5,000 g) and wide frequency content (100-10,000 Hz). FE (finite-element) shock analysis is difficult because implicit linear FE software commonly used for most vibration analysis in aerospace does not account for shock wave propagation, reflection, and attenuation that occurs based upon the distance from the shock source at the base of the spacecraft and the attenuations that occurs through mechanical joints. Spacecraft …

Physical Testing Of Potential Football Helmet Design Enhancements, Michael Jeremy Schuster

Master's Theses

Football is a much loved sport in the United States. Unfortunately, it is also hard on the players and puts them at very high risk of concussion. To combat this an inventor in Santa Barbara brought a new design to Cal Poly to be tested.

The design was tested in small scale first in order to make some preliminary conclusions about the design. In order to fully test the helmet design; however, full scale testing was required. In order to carry out this testing a drop tower was built based on National Operating Committee on Standards for Athletic Equipment, NOCSAE, …

Hilbert-Huang Transform Transient Analysis Of Composite Panel Undergoing High-Velocity Impact, Seungkyu Lee

Seungkyu Lee

Fast Fourier transform (FFT) has been widely used to analyze distribution patterns of frequency components in dynamic response signals. Given a stationary dynamic response signal, a fixed frequency distribution pattern can be obtained efficiently using FFT. If the system of concern is not stationary, however, the frequency distribution pattern varies with time, and the variation in that pattern cannot be effectively determined via FFT. To overcome this weakness, time-frequency dual-domain signal analysis methods such as wavelet transform and Hilbert-Huang transform (HHT) have been introduced. HHT has been shown to be particularly effective in analysis of nonstationary signals obtained from non-linear …