admin The NASA/JPL Environmental Test Laboratory (ETL) developed and built a tunable beam shock test bench based on a design from Sandia National Laboratory many years ago. ETL has been using this test system successfully since October 2008. The excitation is provided by a projectile driven… Read more
I recently rode in the above French TER, Electric Train, Model Z 24500, Lyon to Annecy. A sample accelerometer time history is shown above. The sensor was mounted on a passenger car floor, a Slam Stick X, sampled at 400 samples/sec. The spectrogram of the… Read more
I recently flew as a passenger on a E190 similar to the one in the top image. The landing shock is shown in the bottom image. The data was recorded on a Slam Stick X, sampled at 400 samples/sec. The initial set of peaks have… Read more
Image Courtesy of Justin Kane I recently flew as a passenger on a A330-200 similar to the one in the image. I used a Slam Stick X Vibration Data Logger to measure the landing shock, with the sensor mounted on the cabin floor. The acceleration… Read more
Ideally, a modal test on a structure would be performed with completely free boundary conditions. This configuration can be approximated by mounting the structure on compliant air cushions, or by suspending it with elastic cords, so that the mounted natural frequency is much smaller that… Read more
I recently flew as a passenger on a A320 similar to the one in the image. I used a Slam Stick X Vibration Data Logger to measure the landing shock, with the sensor mounted on the cabin floor. The resulting acceleration time history is shown… Read more
(Click here for better image of Matlab GUI screenshot) I have added an “Exponential Decay” option to the wavelet synthesis function in the Matlab GUI package. The goal is to synthesize a wavelet series that has a gradual overall exponential decay, somewhat similar to an… Read more
I have added batch processing as an option for time histories as shown above. I will add more options in upcoming revisions. The Vibrationdata Matlab GUI package is given at: Vibrationdata Matlab Signal Analysis Package Here are some sample input files for practicing batch processing: batch_sample.mat… Read more
An engineer recently asked me to recommended a vibration test level for his device, which would typically be mounted on a hospital table, including surgical tables. Well… shock would almost certainly be worse than vibration, particularly if the device were somehow accidentally dropped on… Read more
Ring Laser Gyros Acronyms: IMU – inertial measurement unit INS – inertial navigation system RLG – ring laser gyro * * * An INS uses the output from an IMU, and combines the information on acceleration and rotation with initial information about position, velocity and… Read more