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Poole, L. R.

Publications and source records attributed to Poole, L. R..

61 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Postflight simulation of parachute deployment dynamics of Viking qualification flight tests

Simulation calculations of the Viking qualification flight tests are conducted by use of analytical models of the parachute deployment dynamics process. Results from the study indicate that good simulations of event times and trajectory are obtained. If the full-scale parachute drag coefficient is used, a good simulation of first opening load is obtained and the overall nature of the load history is calculated. For longitudinal motions, the two-degree-of-freedom models give good agreement with a six-degree-of-freedom model. It is believed that the analytical models used are tools which will aid in the analysis of future flight systems.

Whitlock, C. H.↗
NASA NTRS1973

Numerical solution of equations governing longitudinal suspension line wave motion during the parachute unfurling process

Equations are presented which govern the dynamics of the lines-first parachute unfurling process, including wave motion in the parachute suspension lines. Techniques are developed for obtaining numerical solutions to the governing equations. Histories of tension at test data, and generally good agreement is observed. Errors in computed results are attributed to several areas of uncertainty, the most significant being a poorly defined boundary condition on the wave motion at the vehicle-suspension line boundary.

Poole, L. R.↗
NASA NTRS1973

Effect of suspension-line viscous damping on parachute opening load amplification.

A digital computer program was used to investigate the effects of suspension-line viscous damping on the opening loads of a high-altitude parachute system having a specified configuration. It was found (1) that the nonlinear elastic characteristics of the suspension system produce an amplification of the opening load when the viscous damping is negligible, (2) that the load amplification is markedly reduced when the suspension-line viscous damping coefficient is increased, and (3) that the suspension-line viscous damping is an important parameter of opening load amplification for high-velocity parachute inflations.

Poole, L. R.↗
NASA NTRS1972

Computer program for investigating effects of nonlinear suspension-system elastic properties on parachute inflation loads and motions

A computer program is presented by which the effects of nonlinear suspension-system elastic characteristics on parachute inflation loads and motions can be investigated. A mathematical elastic model of suspension-system geometry is coupled to the planar equations of motion of a general vehicle and canopy. Canopy geometry and aerodynamic drag characteristics and suspension-system elastic properties are tabular inputs. The equations of motion are numerically integrated by use of an equivalent fifth-order Runge-Kutta technique.

Poole, L. R.↗
NASA NTRS1972

Evaluation of massless-spring modeling of suspension-line elasticity during the parachute unfurling process

A general theory on mathematical modeling of elastic parachute suspension lines during the unfurling process was developed. Massless-spring modeling of suspension-line elasticity was evaluated in detail. For this simple model, equations which govern the motion were developed and numerically integrated. The results were compared with flight test data. In most regions, agreement was satisfactory. However, poor agreement was obtained during periods of rapid fluctuations in line tension.

Poole, L. R.↗