scholarly journals Dynamic Optical Investigations of Hypervelocity Impact Damage

Author(s):  
Leslie E. Lamberson ◽  
Ares J. Rosakis

Hypervelocity impact is a rising concern in spacecraft missions where man-made debris in low-earth orbit as well as micrometeroids have the potential to damage not only the structural components, but also the optical, electrical, and thermal components of a space asset. Little has been investigated regarding damage mechanisms and dynamic fracture mechanics resulting from a hypervelocity impact in-situ. Two optical techniques, the methods of photoelasticity and caustics, in conjunction with high-speed photography are used to examine stress waves from impact of unloaded plates, as well as pre-cracked and pre-loaded plates in tension. The resulting photographs are analyzed to extract information regarding stress wave interactions, crack speeds and the dynamic stress field ahead of the moving cracks.

Author(s):  
Leslie E. Lamberson ◽  
Ares J. Rosakis

Hypervelocity impact is a rising concern in spacecraft missions where man-made debris in low-earth orbit as well as micrometeroids have the potential to damage not only the structural components, but also the optical, electrical, and thermal components of a space asset. Little has been investigated regarding damage mechanisms and dynamic fracture mechanics resulting from a hypervelocity impact in-situ. Two optical techniques, the methods of photoelasticity and caustics, in conjunction with high-speed photography are used to examine stress waves from impact of unloaded plates, as well as pre-cracked and pre-loaded plates in tension. The resulting photographs are analyzed to extract information regarding stress wave interactions, crack speeds and the dynamic stress field ahead of the moving cracks.


2020 ◽  
Vol 225 ◽  
pp. 115836 ◽  
Author(s):  
Bert Swart ◽  
Yubin Zhao ◽  
Mohammed Khaku ◽  
Eric Che ◽  
Richard Maltby ◽  
...  

Author(s):  
Heather M. Cowardin ◽  
John M. Hostetler ◽  
James I. Murray ◽  
Jacqueline A. Reyes ◽  
Corbin L. Cruz

AbstractThe NASA Orbital Debris Program Office (ODPO) develops, maintains, and updates orbital debris environmental models, such as the NASA Orbital Debris Engineering Model (ORDEM), to support satellite designers and operators by estimating the risk from orbital debris impacts on their vehicles in orbit. Updates to ORDEM utilize the most recent validated datasets from radar, optical, and in situ sources to provide estimates of the debris flux as a function of size, material density, impact speed, and direction along a mission orbit. On-going efforts within the NASA ODPO to update the next version of ORDEM include a new parameter that highly affects the damage risk – shape. Shape can be binned by material density and size to better understand the damage assessments on spacecraft. The in situ and laboratory research activities at the NASA ODPO are focused on cataloging and characterizing fragments from a laboratory hypervelocity-impact test using a high-fidelity, mock-up satellite, DebriSat, in controlled and instrumented laboratory conditions. DebriSat is representative of present-day, low Earth orbit satellites, having been constructed with modern spacecraft materials and techniques. The DebriSat fragment ensemble provides a variety of shapes, bulk densities, and dimensions. Fragments down to 2 mm in size are being characterized by their physical and derived properties. A subset of fragments is being analyzed further in NASA’s Optical Measurement Center (OMC) using broadband, bidirectional reflectance measurements to provide insight into the optical-based NASA Size Estimation Model. Additionally, pre-impact spectral measurements on a subset of DebriSat materials were acquired for baseline material characterization. This paper provides an overview of DebriSat, the status of the project, and ongoing fragment characterization efforts within the OMC.


Author(s):  
G. S. Sohoni ◽  
M. V. Walame ◽  
V. Tandon ◽  
R. S. Mahajan ◽  
S. Raju

This paper reviews experimental as well as computational techniques for determining stress-strain characteristics of materials at high strain rates. Quasi-static and dynamic compression tests were performed on standard Lead (Pb) specimens of three different L/D ratios, 0.8, 2 and 3. A Drop tower system was used to achieve different strain rates along with high-speed camera to capture the vertical and radial deformation of specimen and accelerometers to capture load data. The results obtained from the experiments were processed to generate dynamic stress-strain curve for Lead under different strain rate conditions. It was observed that the dynamic stress increases with increasing strain rate. The information gained is valuable for validating constitutive models.


2003 ◽  
Vol 29 (1-10) ◽  
pp. 307-316 ◽  
Author(s):  
Giles A. Graham ◽  
Anton T. Kearsley ◽  
Ian P. Wright ◽  
Mark J. Burchell ◽  
Emma A. Taylor

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