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Lalli, V. R.

Publications and source records attributed to Lalli, V. R..

33 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

ASDTIC: A feedback control innovation

The ASDTIC (Analog Signal to Discrete Time Interval Converter) control subsystem provides precise output control of high performance aerospace power supplies. The key to ASDTIC operation is that it stably controls output by sensing output energy change as well as output magnitude. The ASDTIC control subsystem and control module were developed to improve power supply performance during static and dynamic input voltage and output load variations, to reduce output voltage or current regulation due to component variations or aging, to maintain a stable feedback control with variations in the loop gain or loop time constants, and to standardize the feedback control subsystem for power conditioning equipment.

Lalli, V. R.↗
NASA NTRS1971

Design features and results from fatigue reliability research machines.

The design, fabrication, development, operation, calibration and results from reversed bending combined with steady torque fatigue research machines are presented. Fifteen-centimeter long, notched, SAE 4340 steel specimens are subjected to various combinations of these stresses and cycled to failure. Failure occurs when the crack in the notch passes through the specimen automatically shutting down the test machine. These cycles-to-failure data are statistically analyzed to develop a probabilistic S-N diagram. These diagrams have many uses; a rotating component design example given in the literature shows that minimum size and weight for a specified number of cycles and reliability can be calculated using these diagrams.

Lalli, V. R.↗
NASA NTRS1971

Reliability testing and demonstration - Aerospace problems.

Several aerospace problems are solved using various reliability methods. The problems considered are associated with distribution functions, sampling, accelerated life testing, and accept/reject decisions with sequential testing. In addition, two reliability case histories are described in detail. They include the second space Electric Rocket Test (SERT II), and the Microthruster Power Conditioner (MTPC) life test, both conducted by the Lewis Research Center.

Lalli, V. R.↗
NASA NTRS1968

Pyrotechnic device provides one-shot heat source

Pyrotechnic heater provides a one-shot heat source capable of creating a predetermined temperature around sealed packages. It is composed of a blend of an active chemical element and another compound which reacts exothermically when ignited and produces fixed quantities of heat.

Haller, H. C.↗