Circuit Theory

Contains a report on a research project

Circuit Theory

Contains a report on a research project.Lincoln Laboratory (Purchase Order DDL-B-00306)United States ArmyUnited States NavyUnited States Air Force (Contract AF19(604)-5200

The application of the scanning electron microscope to studies of current multiplication, avalanche breakdown and thermal runaway. Part 2 - General studies, mainly non-thermal

Scanning electron microscope applications in study of current multiplication, avalanche breakdown, and thermal runaway - Nonthermal effects in Read diode

The application of the scanning electron microscope to studies of current multiplication, avalanche breakdown and thermal runaway. Part 1 - General physical basis

Scanning electron microscope applications in study of current multiplication, avalanche breakdown, and thermal runaway - Physical basi

Results of tests OA26 and IA16 in the NASA/ARC 3.5-foot hypersonic wind tunnel on an 0.015-scale model (36-OTS) of the space shuttle configuration 140A/B to obtain pressures for venting analysis

Tests were conducted, from November 15 to December 4, 1973, to obtain surface pressure data on an 0.015-scale replica of the Space Shuttle Vehicle 4. Data were obtained at Mach numbers of 5.3, 7.4, and 10.3, to support the venting analysis for both launch and entry conditions. These tests were the final tests in a series covering a Mach number range from 0.6 to 10.3. The model was instrumented with pressure orifices in the vicinity of the cargo bay door hinge and parting lines, and on the side of the fuselage at the crew compartment, and below the orbital maneuvering system pods at the aft compartment. The model was tested at angles of attack and sideslip consistent with expected divergencies from the nominal trajectory

The Use and Explanation of the Phase Angle in Forced Vibration Testing

Forced vibration testing is a tool used to characterize a structure’s dynamic properties. When subjecting a structure to a forced harmonic load, the results help define the structure’s fundamental frequencies and dominant mode shapes. However, when conducting testing, it is difficult to determine the contributions of each mode to the response at a given location in the structure. The recorded response from a forced vibration test is a combination of unknown modal constituents. Excitation may not result in the pure, single mode response that the experimenter desires, but may instead result in a combination of modal responses that obscure the recorded data or even weaken the overall response. The phase angle is the lag in the response of the structure to the applied harmonic load. Often, engineers focus on the amplitude of the response but overlook the phase angle in their analysis. The investigation conducted herein used a configurable three-story MATLAB model capable of simulating forced vibration tests to determine the role of the phase angle in forced vibration testing. The results produced by the model were also used to analyze modal contributions to the structural response. A data-driven numerical approach and algebraic theoretical approach were both used to characterize the harmonic response. This study describes how the phase angle could indicate when modal contamination occurs, helping engineers filter forced vibration results and understand when a pure mode response is being achieved

Circuit Theory and Design

Contains research objectives.Lincoln Laboratory, Purchase Order DDL B-00306U. S. ArmyU. S. NavyU. S. Air Force under Air Force Contract AF19(604)-740