Debris Cloud Material Characterization for Hypervelocity Impacts of Single- and Multimaterial Projectiles on Thin Target Plates

Schonberg, William P.

doi:10.1155/1995/390721

Cited by 14 publications

(5 citation statements)

References 4 publications

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“…Literature reports on HVI experiments also indicated projectile breakup within the BFDC. 11,49 However, for a h nom = 3.18 mm and v 0 ≈3,000 m/s, evidence of a mostly intact projectile emerging from the BFDC is noted (Figure 3b).…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…The debris cloud consists of ejected materials, and the nature of the debris cloud changes depending on v 0 and h nom . Specifically, the characteristic of the BFDC have been studied extensively for evaluating materials’ protective capabilities due to HVI. ,,, In addition, polymer properties at ultrahigh strain rates can be assessed from the BFDC data.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Specifically, the characteristic of the BFDC have been studied extensively for evaluating materials' protective capabilities due to HVI. 11,25,26,49 In addition, polymer properties at ultrahigh strain rates can be assessed from the BFDC data.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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High Strain Rate Failure Behavior of Polycarbonate Plates due to Hypervelocity Impact

2022

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Developing a fundamental understanding of how polymers respond during hypervelocity impact (HVI), a high strain rate process, is crucial for the potential use of polymers in HVI protection systems. Here, we present the high-strain-rate impact behavior of commercially available polycarbonates with two different molecular weights, 42 and 21 kg/mol. A powder gun and a two-stage light-gas gun were used to achieve the velocities (v0) of a 4 mm projectile impacting the polycarbonate targets over the range of 400–6,500 m/s. The deformation behavior of the polymer during the impact event was captured using high-speed cameras. The impact caused a variety of responses, ranging from deflection of the projectile to complete perforation for higher v0, leading to major debris cloud formation. These debris clouds consist of both fluid- and dust-like ejecta. The fluid-like debris cloud indicates the melting of polymer caused by the conversion of kinetic energy to thermal energy and subsequent adiabatic heating. The dust-like response can likely be attributed to the brittle failure behavior of polymers, as the polymer became brittle at a high strain rate. Dynamic mechanical analysis (DMA) and dielectric thermal analysis (DETA) on the polycarbonate samples used here indicate an approximately 40 °C increase of T g with increasing frequency from 1 Hz to 106 Hz, and such an increase has likely led to brittle behavior. While the leading-edge velocity of the debris clouds and perforation diameters scale linearly with v0, we found negligible differences in the HVI response for the two molecular weights of polycarbonate tested here. This study displays the importance of v0 and thickness contributing to responses of polycarbonates undergoing HVI.

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Section: ■ Results and Discussionmentioning

confidence: 98%

Section: Results and Discussionmentioning

confidence: 99%

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High Strain Rate Failure Behavior of Polycarbonate Plates due to Hypervelocity Impact

2022

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“…We estimate that the exit and middle-layer hole diameters can grow by up to a factor of thirty from the original particle diameter to account for the gas cloud expansion. 31 Our model indicates that the hole areas after three years on-orbit would be 0.1 parts-permillion (ppm) by surface area for entry holes on both sides, 50 ppm for exit holes on both sides, and 150 ppm for middle-layer holes. The expected number of entry holes is about 5 × 10 5 , whereas the expected number of exit holes is <400.…”

Section: Micrometeoroid Holesmentioning

confidence: 93%

Overview and reassessment of noise budget of starshade exoplanet imaging

Lisman

Shaklan

et al. 2021

J. Astron. Telesc. Instrum. Syst.

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High-contrast imaging enabled by a starshade in formation flight with a space telescope can provide a near-term pathway to search for and characterize temperate and small planets of nearby stars. NASA's Starshade Technology Development Activity to TRL5 (S5) is rapidly maturing the required technologies to the point at which starshades could be integrated into potential future missions. We reappraise the noise budget of starshade-enabled exoplanet imaging to incorporate the experimentally demonstrated optical performance of the starshade and its optical edge. Our analyses of stray light sources-including the leakage through micrometeoroid damage and the reflection of bright celestial bodies-indicate that sunlight scattered by the optical edge (i.e., the solar glint) is by far the dominant stray light. With telescope and observation parameters that approximately correspond to Starshade Rendezvous with Roman and Habitable Exoplanet Observatory (HabEx), we find that the dominating noise source is exozodiacal light for characterizing a temperate and Earth-sized planet around Sun-like and earlier stars and the solar glint for later-type stars. Further, reducing the brightness of solar glint by a factor of 10 with a coating would prevent it from becoming the dominant noise for both Roman and HabEx. With an instrument contrast of 10 −10 , the residual starlight is not a dominant noise, and increasing the contrast level by a factor 10 does not lead to any appreciable change in the expected science performance. If unbiased calibration of the background to the photon-noise limit can be achieved, Starshade Rendezvous with Roman could provide nearly photon-limited spectroscopy of temperate and Earth-sized planets of F, G, and K stars <4 parsecs away, and HabEx could extend this capability to many more stars <8 parsecs. Larger rocky planets around stars <8 parsecs would be within the reach of Roman. To achieve these capabilities, the exozodiacal light may need to be calibrated to a precision better than 2% and the solar glint to better than 5%. Our analysis shows that the expected temporal variability of the solar glint is unlikely to hinder the calibration, and the main challenge for background calibration likely comes from the unsmooth spatial distribution of exozodiacal dust in some stars. Taken together, these results validate the optical noise budget and technology milestones adopted by S5 against key science objectives and inform the priorities of future technology developments and science and industry community partnerships. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…We estimate that the exit and middle-layer hole diameters can grow by up to a factor of thirty from the original particle diameter to account for the gas cloud expansion. 29 Our model indicates that the hole areas after three years on-orbit would be 0.1 parts-per-million (ppm) by surface area entry holes on both sides, 50 ppm exit holes on both sides, and 150 ppm middle-layer holes. The expected number of entry holes is about 5 × 10 5 , while the expected number of exit holes is < 400.…”

Section: Micrometeoroid Holesmentioning

confidence: 94%

Overview and Reassessment of Noise Budget of Starshade Exoplanet Imaging

Lisman

Shaklan

et al. 2020

Preprint

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High-contrast imaging enabled by a starshade in formation flight with a space telescope can provide a near-term pathway to search for and characterize temperate and small planets of nearby stars. NASA's Starshade Technology Development Activity to TRL5 (S5) is rapidly maturing the required technologies to the point at which starshades could be integrated into potential future missions. Here we reappraise the noise budget of starshade-enabled exoplanet imaging to incorporate the experimentally demonstrated optical performance of the starshade and its optical edge. Our analyses of stray light sources -including the leakage through micrometeoroid damage and the reflection of bright celestial bodies -indicate that sunlight scattered by the optical edge (i.e., the solar glint) is by far the dominant stray light. With telescope and observation parameters that approximately correspond to Starshade Rendezvous with Roman and HabEx, we find that the dominating noise source would be exozodiacal light for characterizing a temperate and Earth-sized planet around Sun-like and earlier stars and the solar glint for later-type stars. Further reducing the brightness of solar glint by a factor of 10 with a coating would prevent it from becoming the dominant noise for both Roman and HabEx. With an instrument contrast of 10 −10 , the residual starlight is not a dominant noise; and increasing the contrast level by a factor 10 would not lead to any appreciable change in the expected science performance. If unbiased calibration of the background to the photon-noise limit can be achieved, Starshade Rendezvous with Roman could provide nearly photon-limited spectroscopy of temperate and Earth-sized planets of F, G, and K stars < 4 parsecs away, and HabEx could extend this capability to many more stars < 8 parsecs. Larger rocky planets around stars < 8 parsecs would be within the reach of Roman. To achieve these capabilities, the exozodiacal light may need to be calibrated to a precision better than 2% and the solar glint better than 5%. Our analysis shows that the expected temporal variability of the solar glint is unlikely to hinder the calibration, and the main challenge for background calibration likely comes from the unsmooth spatial distribution of exozodiacal dust in some stars. Taken together, these results validate the optical noise budget and technology milestones adopted by S5 against key science objectives and inform the priorities of future technology developments and science and industry community partnerships.

show abstract

Debris Cloud Material Characterization for Hypervelocity Impacts of Single- and Multimaterial Projectiles on Thin Target Plates

Cited by 14 publications

References 4 publications

High Strain Rate Failure Behavior of Polycarbonate Plates due to Hypervelocity Impact

High Strain Rate Failure Behavior of Polycarbonate Plates due to Hypervelocity Impact

Overview and reassessment of noise budget of starshade exoplanet imaging

Overview and Reassessment of Noise Budget of Starshade Exoplanet Imaging

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