Investigations of Parachute Fabric Permeability Under An Unsteady Pressure Differential

Rondeau, Nichole C.; Fitek, John; Desabrais, Kenneth J.; Gibson, Phillip; Godfrey, Thomas; Willis, David J.

doi:10.2514/6.2013-1347

Cited by 6 publications

(3 citation statements)

References 7 publications

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“…24 The Viking parachute canopy has low air permeability, and its effective porosity is 0.0762. To investigate the effect of canopy permeability on breathing phenomenon of supersonic disk-gap-band parachute, The average range of canopy effective porosity is generally about 0–0.3, 25 therefore, the effective porosity of the canopy fabric are selected as 0.01, 0.15 and 0.3, respectively, as shown in Table 1. The opening speed of the parachute system is 1.4 Ma.The mesh model of the canopy and flow field domain is shown in Figure 4.…”

Section: Geometric and Numerical Modelmentioning

confidence: 99%

Influence of fabric permeability on breathing phenomenon of supersonic parachute

Nie

et al. 2023

Journal of Industrial Textiles

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In order to investigate the dynamics and vortex shedding of flexible supersonic canopies, a compressible permeability model combined with fabric structure parameters is proposed, and the periodic oscillation of the supersonic parachute which is referred to as breathing phenomenon is simulated based on the Arbitrary Langrangian Eulerian (ALE) method. The calculated results by new permeability model are consistent with the experimental results. The underlying mechanism of canopy breathing motion is then investigated. Moreover, the influence of canopy permeability on breathing phenomenon of supersonic parachute is analyzed. The results indicate that the periodic growth and shedding of the canopy vortex causes the variation of the pressure differential, which finally lead to the periodic oscillation of the canopy. With the increase of fabric permeability, the vortex rolled up from the canopy skirt move backward and become more slender. The influence of vortex shedding on canopy breathing motion weakened. Those lead to the decrease of the average value of canopy projected area and parachute dynamic load. So are the oscillation amplitude and frequency. The parachute deceleration performance decreases while the parachute swing angle decreases as the canopy permeability increases.

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Section: Geometric and Numerical Modelmentioning

confidence: 99%

Influence of fabric permeability on breathing phenomenon of supersonic parachute

Nie

et al. 2023

Journal of Industrial Textiles

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“…This difference can be minimized with a tighter weave. Moreover, a tighter weave will result in weaker shocks in the parachute's canopy (Rondeau et al, 2013) Repeated use (and abuse) of parachutes in practice leads to micro-and macro-structural irregularities in their material. Marie Havlova (2014) has studied the relationship between air permeability and structural change of the fabric and adopted an image analysis technique to determine air permeability.…”

Section: Introductionmentioning

confidence: 99%

Prediction of bursting strength of the nylon parachute fabrics

Raj

Devi

2021

IJCST

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PurposeParachutes are equipment that is repeatedly used as and when needed. Some of them are used for as many as 60 jumps. The property of the canopy fabric gets deteriorated with use. It is evaluated by destructive tensile and bursting strength. This study aims to focus on the nondestructive evaluation of the canopy fabric's fitness by testing air permeability and relating it with bursting strength. Predictor equations were developed to determine bursting strength from air permeability values.Design/methodology/approachANOVA techniques and statistical regression equations were formed.FindingsA series of samples containing five parachutes fabrics was used seven times, and their air permeability and bursting strength were determined to find the extent to the effect of reuse of parachute fabrics on their bursting strength and air permeability determination. It was found that there was a progressive drop in bursting strength and an increase in air permeability. An investigation of the extent of determination in terms of bursting strength and an increase in air permeability following the sense of five different types of parachute fabrics is reported.Research limitations/implicationsThe work focuses on the prediction of bursting strength to textile materials only and may not apply to other materials like membranes and sheets. The process of determining air permeability is relatively simpler and faster.Practical implicationsThe bursting strength can be predicted for used parachutes, which are otherwise subjected to destructive testing.Social implicationsThe men using the parachutes can be assured of the superior flawless performance of the parachute as equipment and also contribute to the saving of resources due to nondestructive testing, 100% evaluation of all parachutes is possible.Originality/valueThis article describes the nature of the test procedure and discusses the means of introducing it to users of parachutes. It is accepted that the method must undergo field evaluation and possible modification before it can become a routine tool of parachute using organizations.

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“…Goglia [1] determined the air permeability of standard nylon parachute cloths, and verified that the air permeability equation of parachute cloths is consistent with Ergun formula through the statistical analysis of a large number of experimental data. Rondeau [2,3] presented an apparatus for assessing permeability of textiles subjected to time-varying differential pressure. The results indicate a small effect of unsteady differential pressure on the fabric porosity.…”

Section: Introductionmentioning

confidence: 99%

Similarity criteria for canopy porosity and environmental impact analysis of air permeability

Zhang

He³

et al. 2020

Journal of Industrial Textiles

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The porosity is one of the important properties of canopy fabric, which affects the stability, aerodynamic performance and inflation performance of parachutes. The similarity criteria for canopy porosity were presented on the principle of similarity analysis. The Ergun theory of porous medium was introduced to establish the model of air permeability and differential pressure between canopies fully considering the air flow property during decelerating process of parachutes. And the differential pressure equation of micro-pore jets of fabric was established based on Bernoulli's theorem. Then, a novel model of air permeability for parachute canopy under different flying environment was proposed. The air permeability calculated by the model is in good agreement with the experiment. According to different environmental conditions, the impact analysis of air permeability and effective permeability of parachute canopies was studied. The results show that geometric and dynamic similarity are sufficient conditions for porous similarity of canopy. The air permeability and effective permeability of canopy are positively correlated with flight velocity and air density, negatively correlated with aerodynamic viscosity and less affected. There exists blockage effect in micro-pore jets of fabric.

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Investigations of Parachute Fabric Permeability Under An Unsteady Pressure Differential

Cited by 6 publications

References 7 publications

Influence of fabric permeability on breathing phenomenon of supersonic parachute

Influence of fabric permeability on breathing phenomenon of supersonic parachute

Prediction of bursting strength of the nylon parachute fabrics

Similarity criteria for canopy porosity and environmental impact analysis of air permeability

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