admin Introduction Spacecraft must withstand vibration from pre-launch transportation and from powered flight. The spacecraft is not powered during these events. In addition, a spacecraft must withstand “microvibration” or “jitter” from its own moving parts once it reaches orbit and becomes operational. This vibration is… Read more
PowerPoint File: webinar_19_digital_filtering.ppt Audio/Visual File: NESC Academy Digital Filtering – Recommend viewing in Firefox with Sliverlight plugin * * * Python version: webinar_19_digital_filtering_python.ppt Python script: Python Signal Analysis Package GUI * * * Data: sm.txt – unscaled relative displacement vs. time (sec) * * * Reference… Read more
Method 1 Secondary & Component loads can be specified in the form of a Mass-Acceleration curve as described in: NASA-STD-5002, Paragraphs 4.2.1.2, 5.3.2, 5.4. The Mass-Acceleration curve can be derived from measured flight or test data, or analytical loads. Care must be taken to avoid… Read more
PowerPoint File: webinar_18_force_VRS.pptx Audio/Visual File: NESC Academy Force_VRS * * * Python version: webinar_18_force_VRS_python.pptx – Recommend viewing in Firefox with Sliverlight plugin Python script: Python Signal Analysis Package GUI * * * Reference Papers: The Steady-state Response of Single-degree-of-freedom System to a Harmonic Excitation Force: sforce.pdf… Read more
NASA-STD-5002, Load Analyses of Spacecraft and Payloads, 1996 5.3.2 Transient load analysis (excerpt) Statistical variation of parameters governing the forcing functions is accommodated by generating multiple cases of forcing functions for a single flight event. After all cases are analyzed, the maximum transient load is… Read more
PowerPoint File: webinar_17_SDOF_force.pptx Audio/Visual File: NESC Academy SDOF – Response to Applied Force – Recommend viewing in Firefox with Sliverlight plugin * * * Reference Papers: T. Irvine, Machine Mounting for Vibration Attenuation, Rev B, Vibrationdata, 2000 link Bruel & Kjaer Booklets: Mobility Measurement link Modal… Read more
PowerPoint File: Webinar_16_VRS.pptx Audio/Visual File: NESC Academy VRS – Recommend viewing in Firefox with Sliverlight plugin * * * Python Version Webinar_16_VRS_python.pptx Python script: Python Signal Analysis Package GUI * * * PSD Data Files: webinar_16_data_files.mat webinar_16_data_files.zip * * * Reference Paper: An Introduction to the… Read more
Here is a paper which gives a derivation of the equations of motion: semidefinite_force.pdf It also covers the transfer functions which can be calculated if the rigid-body mode is omitted. Here is a Matlab script: semidefinite_force.zip The main script is: semidefinite_force.m The remaining scripts are… Read more
TTL = Transistor–transistor logic Here is a Matlab script to convert a TTL tachometer signal from a motor shaft encoder into a cycles per second (CPS) vs. time plot. ttl_cps.m The script’s cycle detection criterion might need adjustment for a given encoder system. Please send… Read more
PowerPoint File: webinar_15_SDOF_frequency_domain.ppt Audio/Visual File: NESC Academy SDOF_response_base_input_frequency_domain – Recommend viewing in Firefox with Sliverlight plugin * * * PSD Data File: navmat_spec.psd * * * Python webinar_15_SDOF_frequency_domain_python.pptx Python script: Python Signal Analysis Package GUI * * * Reference Papers: Equivalent Static Loads for Random Vibration link… Read more