US-12625020-B2 - Photonic shock and impulse (PSI) gauge

Abstract

An apparatus for measuring movement of a test specimen, where the apparatus includes an electromagnetic transducer and an optical probe. The apparatus may include a test specimen holder and a body that move together. The optical probe may be configured to direct an optical beam through the body to the test specimen, which may provide for measurement of a prompt impulse. The electromagnetic transducer may be configured to produce a voltage when the test specimen holder and the body move, which may provide for measurement of a total impulse of the same test specimen. Thus, a single gauge may provide for measuring both prompt impulse and total impulse of the same test specimen.

Inventors

• George Williams
• Todd Evan Vande Brake
• Gary Lee Paderewski

Assignees

• ANALEX CORPORATION

Dates

Publication Date

20260512

Application Date

20231005

Claims (20)

1. 1 . An apparatus for measuring movement of a test specimen, the apparatus comprising: a transducer housing; a test specimen holder that is configured to hold the test specimen and configured to move relative to the transducer housing when the test specimen moves relative to the transducer housing; a body that is fixed relative to the test specimen holder such that the body moves with the test specimen holder, relative to the transducer housing, when the test specimen translates relative to the transducer housing; an electromagnetic transducer configured to produce a voltage when the test specimen holder and the body move relative to the transducer housing; and an optical probe configured to direct an optical beam through the body to the test specimen.
2. 2 . The apparatus of claim 1 , wherein the electromagnetic transducer comprises one or more transducer bearings that are coupled to the body such that the one or more transducer bearings move with the body when the test specimen holder and the body move relative to the transducer housing.
3. 3 . The apparatus of claim 1 , wherein the electromagnetic transducer comprises a coil winding and a magnet configured to induce a current through the coil winding, thereby producing the voltage, when the test specimen holder and the body move relative to the transducer housing.
4. 4 . The apparatus of claim 1 , wherein the test specimen holder is configured to move in a first direction relative to the transducer housing, and wherein the electromagnetic transducer is configured produce the voltage when the test specimen holder and the body move in the first direction relative to the transducer housing.
5. 5 . The apparatus of claim 1 , wherein the optical probe is configured to move relative to the transducer housing with the body and the test specimen holder.
6. 6 . The apparatus of claim 1 , further comprising an optical probe adjuster configured to adjust focus and/or tip tilt of the optical probe.
7. 7 . The apparatus of claim 1 , further comprising the test specimen.
8. 8 . The apparatus of claim 1 , wherein the test specimen holder further comprises a window that is configured such that the optical beam passes through the window to reach the test specimen.
9. 9 . The apparatus of claim 1 , further comprising a shock isolation system configured to shock isolate a gauge housing, that circumscribes at least a portion of the transducer housing, from the test specimen holder and the body.
10. 10 . The apparatus of claim 1 , further comprising a processor operably coupled to the optical probe and the electromagnetic transducer, wherein the processor is configured to: determine prompt impulse based on a displacement of the test specimen measured by the optical probe when a shockwave propagates through the test specimen; and determine total impulse based on a velocity of the test specimen determined based on the voltage produced by the electromagnetic transducer when the test specimen translates relative to the transducer housing.
11. 11 . A system comprising: the apparatus of claim 1 ; and an X-ray generator, an ion generator, or a laser generator configured to direct an X-ray, ion, or laser to the test specimen.
12. 12 . A method of operating the apparatus of claim 1 comprising producing a shockwave that propagates through the test specimen such that the test specimen is displaced relative to the transducer housing and such displacement is detected by the optical probe.
13. 13 . A method of measuring movement of a test specimen, the method comprising: holding test specimen in a test specimen holder; directing an optical beam from an optical probe through a body, that is fixed relative to the test specimen holder, to the test specimen; producing a shockwave that propagates through the test specimen such that the optical probe measures displacement of the test specimen due to the shockwave; and producing a voltage with an electromagnetic transducer based on movement of the body with the test specimen in a first direction relative to the transducer housing.
14. 14 . The method of claim 13 , wherein the optical beam is directed to the test specimen while the shockwave propagates through the test specimen, which occurs before the voltage is produced by the electromagnetic transducer.
15. 15 . The method of claim 13 , further comprising moving one or more transducer bearings with the body when the specimen holder and the body move in a first direction due to a motivating event that urges the test specimen in the first direction.
16. 16 . The method of claim 13 , further comprising moving a magnet, of the electromagnetic transducer, in the first direction with the body relative to a coil winding of the electromagnetic transducer, thereby inducing a current through the coil winding to produce the voltage.
17. 17 . The method of claim 13 , further comprising moving the optical probe in the first direction with the test specimen holder and the body.
18. 18 . The method of claim 13 , wherein the shockwave propagates through the test specimen for 1 to 10 microseconds, and the electromagnetic transducer produces the voltage for 1 to 10 milliseconds.
19. 19 . The method of claim 13 , further comprising: measuring, with the optical probe, a displacement of the test specimen due to the shockwave; determining a prompt impulse, with a processor, based on the displacement of the test specimen measured by the optical probe; measuring, with an electromagnetic transducer, a velocity of the test specimen due to a motivating event; and determining a total impulse, with a processor, based on the velocity the test specimen measured by the electromagnetic transducer.
20. 20 . The method of claim 13 , further comprising directing an X-ray, ion, or laser for 1 to 10 microseconds to the test specimen from an X-ray generator, an ion generator, or a laser generator, such that the shockwave propagates through the test specimen; and continuing to direct the X-ray, ion, or laser to the test specimen for 1 to 10 milliseconds, such that the test specimen translates in the first direction.

Description

STATEMENT OF GOVERNMENTAL INTEREST This invention was made with Government support under Contract Nos. N00030-20-C-0014 and N00030-15-C-0029 awarded by the United States Navy/Strategic Systems Programs. The U.S. Government has certain rights in the invention. TECHNICAL FIELD The present disclosure relates generally to measurement devices and, in particular, as a photonic shock and impulse gauge for measuring a prompt impulse and a total impulse in thermally mechanically induced shock environments, and a method of using the shock and impulse gauge. BACKGROUND Prompt impulse and total impulse loading on test specimens from an X-ray test environment (or an ionic or direct laser impulse test environment) may be measured by two separate gauges (i.e., one for prompt impulse and another for total impulse), with one test specimen provided in one gauge and a different identical specimen provided in the other gauge. The volume available (e.g., at the National Ignition Facility (NIF) at Lawrence Livermore National Labs) for placing test specimens and instrumentation is limited. In addition, there is a limited amount of time available for testing, and test time can be expensive. Moreover, because each of the two identical test specimens are provided in a different gauge, in practice the test specimens may have different masses during testing (e.g., due to laser ablation of mass of each test specimen during testing) which may invalidate test results. Accordingly, a process and device are needed to reduce testing space and testing time required to measure prompt impulse and total impulse of test specimens in, for example, an X-ray test environment. Moreover, a process and device are needed to reduce or eliminate differences that may occur between the test specimen that is provided for prompt impulse measurement and the counterpart test specimen provided for total impulse measurement. SUMMARY The present application provides for an apparatus for measuring movement of a test specimen, where the apparatus includes an electromagnetic transducer and an optical probe. The apparatus may include a test specimen holder and a body that move together. The optical probe may be configured to direct an optical beam through the body to the test specimen, which may provide for measurement of a prompt impulse. The electromagnetic transducer may be configured to produce a voltage when the test specimen holder and the body move, which may provide for measurement of a total impulse of the same test specimen. Thus, a single gauge may provide for measuring both prompt impulse and total impulse of the same test specimen. For example, the optical probe may provide for determining the prompt impulse based on a displacement (e.g., over time from a vibration due the shockwave that propagates through the test specimen) of the test specimen measured by the optical probe when the shockwave propagates through the test specimen. The electromagnetic transducer may provide for determining the total impulse based on a velocity of the test specimen determined based on the voltage produced by the electromagnetic transducer based on movement of the body, after measurement by the optical probe has completed (e.g., after the shockwave has stopped propagating through the test specimen). Thus, a single apparatus may provide for measuring both a prompt impulse and a total impulse. The apparatus may be a gauge (e.g., a photonic shock and impulse (PSI) gauge). The gauge may include a single transducer housing that houses both at least a portion of the electromagnetic transducer and at least a portion of the optical probe. The gauge may advantageously provide for measurement from both the electromagnetic transducer and the optical probe during the same test of the test specimen. Therefore, the gauge may provide for prompt impulse and total impulse in less time and with less required testing space (e.g., half as much testing space) compared to conducting two different tests with two separate gauges (e.g., one for prompt impulse and another for total impulse). As discussed above, since both prompt impulse and total impulse may be measured for the same test specimen, there may be no variability (or an insignificantly small variability) of the mass of the test specimen when prompt impulse is measured compared to when the total impulse is measured. Thus, a more accurate material model may be generated based on the measured prompt impulse and the measured total impulse of the test specimen, compared to testing methods that require a different test specimen for each measurement. Moreover, because both measurements can be provided taken from a single test specimen, only half the number of test specimens is required compared to testing methods that require a different test specimen for each measurement. Thus, material costs for providing prompt impulse and total impulse may be reduced compared to testing methods that require a different test specimen for each measurement. Th