Beam or Rod Longitudinal Natural Frequencies
Here is a Matlab GUI script and reference paper for calculating the longitudinal natural frequencies of a beam or rod. beam_longitudinal.zip Long.pdf * * * See also: Beam Bending Frequencies – Tom Irvine
Structural Dynamics
Modal Transient Analysis of a Beam with Enforced Motion via a Ramp Invariant Digital Recursive Filtering Relationship
These Matlab scripts calculate the natural frequencies of a beam via the finite element method: beam_base_accel_fea.zip They also have options for base excitation: 1. frequency response function 2. half-sine base input 3. arbitrary base input A ramp invariant digital recursive relationship is used for the… Read more
Rectangular Plate Bending Frequency
Here is a Matlab GUI script for calculating the bending fundamental frequency of a rectangular plate: rectangular_plate_bending.zip * * * See also: Beam Bending Frequencies Structural Dynamics – Classical Methods Page – Tom Irvine Connect with me on LinkedIn
Beam Bending Natural Frequencies & Mode Shapes
A rocket vehicle behaves as a free-free beam during flight. The vehicle’s body bending modes can be excited by wind gusts, aerodynamic buffeting, thrust offset, maneuvers, etc. Note that the mass and stiffness properties vary along the vehicle’s length. Furthermore, the mass properties change with… Read more
Vibration Testing & Analysis Standard References
The European Cooperation for Space Standardization http://www.ecss.nl/ Download: ECSS-E-ST-10-03C, Space Engineering: Testing Spacecraft Mechanical Loads Analysis Handbook: ECSS-E-HB-32-26A_19February2013 Slide summary: ESA_mechanical_loads_handbook_part_1 * * * SMC-S-016, Air Force Space Command, Space and Missile Systems Center, Standard Test Requirements for Launch, Upper-Stage and Space Vehicles, 2014 Download… Read more
North Korean Rocket Failure
Severe vibrations likely brought down N. Korean rocket By George Leopold 4/13/2012 3:15 PM EDT WASHINGTON – The failure of North Korea’s three-stage Unha-3 rocket on Thursday (March 12) was most likely caused by severe vibrations at an early point in the flight trajectory known… Read more
Vibrationdata Newsletter March 2012
I posted a newsletter at: http://www.vibrationdata.com/Newsletters/March2012_NL.pdf The topics are: James Webb Space Telescope Isolation The Prandtl-Glauert Singularity Seneca Guns Loudest Stadium Crowd Please also see my profile at: http://www.nasa.gov/offices/nesc/academy/Tom_Irvine_bio.html Tom Irvine
My Favorite Flight Anomaly
The flight accelerometer data was measured on a launch vehicle which shall remain anonymous. This was due to an oscillating thrust vector control (TVC) system during the burn-out of a solid rocket motor. This created a “tail wags dog” effect. The resulting vibration occurred throughout… Read more
Modal Transient Analysis Numerical Engine, Applied Force
Modal Transient Analysis of a System Subjected to an Applied Force via a Ramp Invariant Digital Recursive Filtering Relationship: force_ramp_invariant.pdf Reference Papers: Smallwood Irvine General Coordinate Irvine Impulse Response Function 1 Irvine Impulse Response Function 2 Irvine SRS * * * * * * * * * *… Read more
Generalized Eigenvalue Problem
The goal of this project is to solve a “very large” generalized eigenvalue problem in a “reasonable” amount of time using library functions. The mass and stiffness matrices may be either dense or sparse. Optimum routines are desired for each case. Here is description of… Read more