Method Article

Conducting Elevated Temperature Normal and Combined Pressure-Shear Plate Impact Experiments Via a Breech-end Sabot Heater System

DOI:

10.3791/57232

⸱

August 7th, 2018

 ,  , 
1Department of Mechanical and Aerospace Engineering, Case Western Reserve University

In This Article

Summary

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

Here, we present a detailed protocol of a new approach for conducting elevated temperature reverse normal plate impact, and combined pressure-and-shear plate impact. The approach involves the use of a breech-end resistive coil heater to heat a sample held at the front-end of a heat-resistant sabot to the desired temperature.

Abstract

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

A novel approach for conducting normal and/or combined pressure-shear plate impact experiments at test temperatures up to 1000 °C is presented. The method enables elevated temperature plate-impact experiments aimed towards probing dynamic behavior of materials under thermomechanical extremes, while mitigating several special experimental challenges faced while performing similar experiments using the conventional plate impact approach. Custom adaptations are made to the breech-end of a single-stage gas-gun at Case Western Reserve University; these adaptations include a precision-machined extension piece made from SAE 4340 steel, which is strategically designed to mate the existing gun-barrel while providing a high tolerance match to the bore and keyway. The extension piece contains a vertical cylindrical heater-well, which houses a heater assembly. A resistive coil heater-head, capable of reaching temperatures of up 1200 °C, is attached to a vertical stem with axial/rotational degrees of freedoms; this enables thin metal specimens held at the front-end of a heat-resistant sabot to be heated uniformly across the diameter to the desired test temperatures. By heating the flyer plate (in this case, the sample) at the breech-end of the gun-barrel instead of at the target-end, several critical experimental challenges can be averted. These include: 1) severe changes in the alignment of the target plate during heating due to the thermal expansion of the several constituents of the target holder assembly; 2) challenges that arise due to the diagnostics elements, (i.e., polymer holographic gratings, and optical probes) being too close to the heated target assembly; 3) challenges that arise for target plates with an optical window, where crucial tolerances between the sample, bond layer, and window become increasingly difficult to maintain at high temperatures; 4) in the case of combined compression-shear plate impact experiments, the need for high-temperature resistant diffraction gratings for the measurement of transverse particle velocity at the free surface of the target; and 5) limitations imposed on the impact velocity necessary for unambiguous interpretation of the measured free surface velocity versus time profile due to thermal softening and possibly yielding of the bounding target plates.By utilizing the adaptations mentioned above, we present results from a series of reverse geometry normal plate impact experiments on commercial purity aluminum at a range of sample temperatures. These experiments show decreasing particle velocities in the impacted state, which are indicative of material softening (decrease in post-yield flow stress) with increasing sample temperatures.

Introduction

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

In engineering applications, materials are subjected to a wide range of conditions, which can be static or dynamic in nature, coupled with high levels of deformation and temperatures ranging from room to near the melting point. Under these thermomechanical extremes the material behavior can vary drastically; thus, over nearly a century, several experiments have been developed aimed towards probing the dynamic response and/or other characteristics of material behavior while under controlled loading regimes1,2,3,4,5,6,7,8,9,10,11,12,13,14. For metals loaded at low to intermediate strain rates (10-6-100 /s), servo-hydraulic or precision screw universal testing machines have been used to study the material response subjected to various loading modes and levels of deformation. But as the applied strain rates increase beyond the intermediate strain rates (i.e., >102/s), other experimental techniques become necessary in order to probe the mechanical response. For example, at loading rates of 103/s up to 5 × 104/s full-sized or miniaturized Split-Hopkinson pressure bars enable such measurements to be made8,15.

Traditionally, light gas-guns and/or explosively driven plate impact experiments have been utilized to study the dynamic inelasticity and other phenomenon such as spallation, or phase transformation that occur with very high strain rates (105-107/s)16,17,18,19,20,21,22, or combinations of high pressures and dynamic loading. Customarily, plate impact experiments involve the launch of a flyer plate carried by a sabot initially at the breech-end of the gas-gun, which then travels down the length of the gun-barrel and is made to collide with a carefully aligned stationary target plate at the impact chamber. As a result of the impact, normal and/or combined pressure and shear stresses are generated at the flyer/target interface, which travel through the spatial dimensions of the plates as longitudinal and/or combined longitudinal and transverse stress waves. The arrival of these waves at the rear surface of the target plate affect the instantaneous free surface particle velocity of the target plate, which is monitored typically via interferometric techniques. In order to allow the interpretation of the measured particle velocity versus time history, it is necessary that plane-waves with a front parallel to the impact surface be generated upon impact14,23. To ensure the former, impact must occur with an impact tilt angle on the order of less than one milli-radian12,24, with impact surfaces of flatness better than a couple micrometers5,25.

Plate impact experiments have been adapted to include heating elements which enable investigations of material behavior to extend into thermomechanical extremes26,27,28,29. These adaptations usually involve the addition of an induction coil, or of a resistive heater element to the target-end of the gas-gun; though these adaptations have been shown to be experimentally feasible, the approach inherently leads to special experimental challenges which require careful considerations. Some of these experimental complications include differential thermal expansion of the various constituents of the target holder assembly and/or alignment fixture while heating the target (sample) plate, which requires in-real-time alignment adjustments, usually made with remotely controlled alignment tools with continuous feedback in order to maintain crucial parallelism tolerance between the sample and target plate. In the case of the pressure-shear plate impact experimental scheme, heating the sample requires conventional polymer gratings be replaced by high-temperature resistant metallic gratings in order to monitor transverse particle velocity at the free surface of the target plate. Moreover, heating of the sample can add limitations on the impact velocity that can be employed in certain experimental schemes, such as in the high strain rate combined pressure-and-shear plate impact configuration, where special considerations may be required to prevent unambiguous interpretation of the experimental results, which are calculated using the acoustic impedance of the front and rear target plates which may be temperature dependent. Lastly, for other experimental schemes, which require a target plate with an optical window, tolerances between the sample, bond layer, and/or coatings become increasingly difficult to maintain at high temperatures19.

To alleviate the experimental challenges mentioned above, we have made custom adaptations to the existing single-stage gas-gun located at Case Western Reserve University (CWRU)7,30,31,32. These modifications enable thin metal specimens held at the front-end of a heat-resistant sabot to be heated to temperatures in excess of 1000 °C, prior to firing, which allow high temperature normal and/or combined pressure-shear plate impact experiments to be conducted. In contrast to most of the conventional approaches employed for elevated temperature plate impact studies, this method has been shown to alleviate several of the experimental challenges described above. For example, this approach has been utilized to feasibly achieve tilt angles of less than one milli-radian without the need for remote tilt adjustment30, or additional optical elements for monitoring tilt changes during the experiment. Second, since the target plate remains under ambient temperatures, this method does not require the need for special high-temperature resistant holographic gratings for the measurement of transverse particle velocity in oblique impact experiments; additionally, higher impact velocities can be utilized without the risk of yielding the target plate, and thus, reduce the complexity in the interpretation of the experimental results. To add, this approach can be utilized to perform high temperature reverse-geometry normal plate impact experiments which provide Us-Up relationships for a choice sample material. These can be obtained via impedance matching techniques, or additionally, an analysis of the rarefaction fan from the back surface of the sample which carry information regarding changes in sample shock velocity during unloading33,34. In the elevated temperature combined pressure-shear plate impact configuration, this approach enables the dynamic inelasticity of thin films to be studied up to a wide temperature and plastic deformation range, and strain-rates up to 107/s depending of the thickness of the thin specimen16,27,29.

We will present the protocols necessary for performing a typical elevated temperature plate impact experiment discussed above. This will be followed by a section dedicated to representative results obtained using the present technique. Lastly, a discussion of the results will be presented prior to a conclusion.

Access restricted. Please log in or start a trial to view this content.

Protocol

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

1. Sample and Target Material Preparation

NOTE: In the following protocol, we will detail the steps necessary for preparing the sample and target materials, which will be later used in a reverse geometry normal plate impact experiment. In this setup, a flyer plate (also the sample), held at the front of a sabot, will be launched via a single stage gas gun and made to impact a stationary target plate housed in the target chamber of the gas gun. A typical flyer and target plate assembly described in the following protocol is shown schematically in Figure 1.

  1. Section a 99.999% commercial purity polycrystalline aluminum rod into disks which will later be used as the flyer plates (samples).
    NOTE: This can be done by using a slow speed saw in order to prevent high temperatures and residual stresses in the work piece.
  2. Face and turn the sample disks on a lathe to a diameter of 76 mm and thickness of 5.6 mm.
  3. Drill three equispaced holes 5 mm in diameter on a 62 mm diameter bold circle on the sample disks, which will later be used to secure the samples to the sabot.
  4. Grind both sides of the sample plates in order to achieve a flatness and parallelism tolerance of nearly 10 µm over the diameter of the samples.
    1. Perform a rough lap on the sample plate surfaces using a commercial lapping machine with relatively coarse particle size (10 - 20 µm).
      NOTE: A weight can be added in this step until the lapped surfaces reach an even dull grey, indicating uniformity across the diameter of the disk.
    2. Carefully clean the lapped samples using ethanol to remove any residual particles, and mineral oil. Then, polish both surfaces of the sample plates using 1 µm diamond paste on a polishing cloth.
    3. Check the flatness of the samples by observing light bands through an optical flat in contact with the surface of interest under a green monochromatic light source16.
      NOTE: Flatness can be quantified by observing the curvature of the light bands on the surface of the sample, or by counting the number of bands across the diameter as shown in Figure 2.
      1. Move-on to the next step if 3 light bands or less are seen across the sample diameter indicating that a flatness of approximately 2 µm. Otherwise, repeat steps 1.4.1 - 1.4.3 until 3 light bands or better is achieved.
  5. Repeat steps 1.1 - 1.3 to fabricate the target plates. Section a precipitation hardened (high strength) alloy rod (Table of Materials) into disks and then machine these to a diameter of 25 mm and thickness of 7 mm. Finally, grind both sides flat to approximately 10 µm.
    1. Lap both surfaces of the target plates on a lapping machine using 15 µm alumina powder in mineral oil until the surfaces achieve an even dull grey appearance.
      NOTE: An equivalent particle size of diamond slurry can be used to achieve faster removal rates, and better surface reflectively. Additionally, weights can be used.
    2. Repeat step 1.4.2.
    3. Check the flatness of the target plates by repeating step 1.4.3. If 1 light band or better is observed proceed to the next step. Otherwise, repeat steps 1.4.1 - 1.4.3 until 1 light band or better is achieved. If holographic gratings are necessary, proceed to step 1.5.4, otherwise skip to step 1.6.
  6. Utilize a similar procedure as described in step 1.1 - 1.3 to fabricate the aluminum ring.
    1. Section an aluminum tube with the outer and inner diameters of 41 mm and 32 mm, respectively, into rings and then face the sides to a thickness of 7 mm.
    2. Drill six 3 mm diameter slots equispaced on a 34.5 mm diameter bolt circle. These will later house six voltage biased copper pins, which will enable tilt measurements to be made at impact.
    3. Grind, lap, clean, and polish both surfaces of the aluminum rings by using the procedures detailed in step 1.4.
  7. Adhere the flat target plate to the aluminum ring using a two-parts epoxy mixture on a flat securing rig as shown in Figure 3. Allow the epoxy to cure overnight at room temperature.
    NOTE: The two parts are secured to a flat steel stage using three screws which are gently hand tightened so that the applied pressures on the target and the ring prevent the epoxy from leaking outwards.
    1. Remove any left-over adhesive from the radial slots or from the surface of the plates using acetone.
    2. Insert the target plate/aluminum ring assembly into the POM ring.
      NOTE: The POM disk will later be mounted on-to a target holder with rotational degrees of freedom, which will allow the alignment of the test materials within the gun-barrel.
    3. Mark the position of the six radial slots on the inner step of the POM ring and drill six thru-thickness holes at the marked locations.
    4. Section 6 copper pins from a spool of 15 AWG enameled copper wire with the length of ~ 50 mm and remove the enameled insulation layer from two of them. Press the pins into the slots in a symmetric pattern: two ground pins are placed in opposite locations of the circle. Push the pins through the slots and leave approximately 2 mm protruding outwards from the surface of the ring.
      NOTE: The pins are used for measuring the tilt angle and provide the trigger signal.
    5. Adhere bent-ends of the copper pins to the rear-surface of the POM ring using extra fast-setting epoxy.
    6. Use a low viscosity two parts epoxy mixture to seal the gap between the aluminum ring and the inner wall of the POM ring. Allow the epoxy to cure overnight at room temperature.
  8. Remove the excess 2 mm of copper pins protruding from the surface of the aluminum ring. First section the excess pins with a rotary tool, and then sand the remaining down to the surface using wet 300 grit sand paper, until pins are nearly flush to the surface of the aluminum ring.
    1. Lap, clean and polish the entire assembly by repeating steps 1.4.1-1.4.3. Ensure that the entire lapped assembly is flat to within 2 - 3 light bands.
    2. Solder the ends of the six copper pins at the back-surface of the POM ring, and mount the POM ring to the target holder using four 6.35 mm diameter POM pins.

2. Assembly of Custom Heat-Resistant Sabot

  1. Gather the assembly components for the heat resistant sabot, shown in Figure 4.
  2. Attach an eyebolt at the bottom-end of the aluminum cap, and secure a sealing O-ring and a PTFE key in the grooves of the cap.
    NOTE: The key and O-ring are used to prevent the tilt and rotation of the sabot during its travel down the gun-barrel.
    1. Pull the thermo-couple wire through the hole on the bottom of the cap, and secure the thermo-couple wire into a connector.
  3. Adhere the cap to the back-end, and the fully-fired alumina silicate Lava rock tube to the front-end of the aluminum tube using two-parts quick setting epoxy.
  4. Pull the thermo-couple probe through the hole in the 76.2 mm diameter H13 tool-steel alloy sample holder.
  5. Adhere the H13 sample holder to the front-end of the Lava tube using high temperature cement, or equivalent high temperature adhesive.
  6. Apply the high temperature cement around the 25 mm diameter and 3 mm thick Lava disk sitting on top of the inner thru-thickness 19 mm diameter concentric hole of the H13 holder. Allow the high temperature cement to dry overnight at room temperature.
  7. Secure the sample to H13 sample holder using three alumina screws, and ensure that the flatness of the sample does not change by using the protocol described in 1.4.3.

3. Assembly of the Test Materials within the Gas-Gun

  1. Clean the front surface of the sample and target with isopropyl alcohol, and then use tape to secure first surface mirrors to the surface of each.
  2. Screw tighten a 3-axis motion stage onto an extruding rod above the gun barrel within the impact chamber, and attach the prism holder carrying a precision optical prism onto the stage.
  3. Pull a rope through the gun barrel, and attach the rope to the sabot via the eyebolt on the aluminum cap.
  4. Place the sabot into gun barrel with the sample facing towards the impact chamber, and place the target holder assembly into the target chamber facing the sample.
  5. Align the position of the target by adjusting the four POM positioning pins until the first-surface mirror on the target is aligned to the first-surface mirror on the sample.
    1. Perform a rough align of the parallelism between the sample and target plates using a diffused bulb and a reflective mirror. Adjust the stage until a single continuous reflected image of the bulb can be seen from all of the surfaces on the alignment prism.
  6. Use an auto-collimator24 to achieve the fine alignment.
    1. Adjust the stage until the reflected image of the cross from the back surface of the prism is aligned with the image reflected from the first-surface mirror on the sample.
    2. Adjust the target assembly by turning the positioning screws on the target holder until the reflected image of the cross from the back surface of the prism is aligned with the image reflected from the first-surface mirror on the target.
  7. Remove the first-surface mirrors from the sample and target. Also remove the reflective mirror, prism, prism holder and the adjustment stage from the impact chamber.
  8. Pull the sabot to the breech-end of gas-gun using the rope, and then remove the rope from the cap.
  9. Leave ~ 2.5 mm distance between the sabot and the heater head and accordingly adjust the length of the screws which prevent the back motion of the sabot towards the breech.
  10. Connect the thermal-couple to the temperature diagnostic monitor.
    NOTE: The thermal-couple wire on the temperature monitor end has been put inside the barrel through the vacuum pipe using a feedthrough.

4. Arrangement and Alignment of the Laser-Based Diagnostics

  1. Put two threaded anchors in the holes on the back of the focuser probe holder. Tighten two screws through the anchors until they reach the POM to enable the freedom to change the incident beam angle.
    1. Drill a thru-thickness hole on the bottom of the focuser probe holder, and secure it on a threaded cylindrical magnet.
    2. Pull an optical fiber focuser probe through an aluminum tube, and glue the probe to the aluminum tube by applying extra fast-set epoxy around the probe head and the tip of the aluminum tube. Push the probe head as forward into the tube as possible, but make sure to leave the probe lens away from epoxy. Wait until the extra fast-set epoxy is hardened.
    3. Connect the optical focuser to the all-fiber-optics NDI/TDI interferometer31, and place the focuser assembly on the target holder aiming towards the rear-surface of the target.
  2. Turn on the laser, in this case a 2W Erbium fiber coupled laser, to 0.2-0.4 W power. Next, adjust the position of the focuser probe using the screws attached on the focuser assembly until proper light coupling is achieved and the acquired signal is optimized.
  3. Adjust the variable ratio coupler to match the intensity of the reference and Doppler-shifted light until the signal shown in the oscilloscope is optimized.
    NOTE: If transverse motion diagnostics are needed, please refer to steps 4.5 - 4.6.
  4. Put two threaded anchors in the holes on the back of the POM focuser holder, and then tighten the two screws through the anchors until they touch the POM.
    1. Drill a thru-thickness hole on the bottom of the focuser probe holder, and secure it on a threaded cylindrical magnet.
    2. Pull an optical fiber collimator probe through an aluminum tube, and glue the probe to the aluminum tube by applying extra fast-set epoxy around the probe head and the tip of the aluminum tube. Push the probe head as forward into the tube as possible, but make sure to leave the probe lens away from epoxy. Wait until the extra fast-set epoxy is hardened.
    3. Repeat the above steps in 4.4 to make two assemblies and put them in the impact chamber.
  5. Adjust the positions and the angles of the receiving optical fiber collimators with the magnet and the two screws on the POM holder until the intensity of the first-order diffracted beams measured by the power monitors is optimized.
  6. Disconnect the power monitor and connect the two receiving collimators to the all-fiber-optics TDI interferometer31.

5. Execution of High Temperature Reverse Geometry Normal/Pressure-Shear Plate Impact Experiments

  1. Secure the primary flange by tightening the four clamps on the entrance of the impact chamber, and then close the chamber using a polyester film bolted to a secondary flange.
  2. Increase the seal pressure to ~207 kPa, and then close the gas-gun at the breech-end by tightening the screws in the flange.
  3. Turn on the breech-end vacuum pump, and then turn on the target chamber-end vacuum pump.
  4. Ensure that there is no motion of the sabot towards the chamber caused by the pressure difference between the front and the back of the sabot. Wait until the chamber is evacuated to a pressure less than 100 mTorr.
  5. Turn on the laser-amplitude-based sabot impact velocity measurement system.
  6. Move the heater down to the marked position and turn on the heater. Increase the temperature of the heater with 100 °C increments until the desired sample temperature is reached.
  7. Pressurize the firing dump chamber to ~1103 kPa, and the load chamber to a desired level depending on the chosen impact velocity. Also, secure the sabot catcher to the impact chamber.
  8. Turn off the heater and immediately move the heater up upwards towards the heater-well. Record the temperature displayed on the temperature diagnostic monitor measured by the sabot thermocouple at the sample surface.
  9. Immediately open the seal valve and release the firing dump chamber once the seal pressure drops to zero.

Access restricted. Please log in or start a trial to view this content.

Results

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

An 82.5 mm bore, 6 m length, single-stage gas gun at CWRU capable of accelerating 0.8 kg projectiles to speeds up to 700 m/s was used in conducting the present experiments. Figure 5 shows a photograph of the modified gas-gun facility at CWRU. Prior to firing, the custom designed sabot is housed within the heater extension piece, shown in Figure 6. The extension piece carries a vertical heater-well enabling a resistive coil heater...

Access restricted. Please log in or start a trial to view this content.

Discussion

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

The method and protocol stated above detailed the procedure for properly performing a reverse geometry normal plate impact experiment at elevated temperatures. In this approach, we make custom modifications to the gun barrel at the high pressure (breech) end of the existing gas gun at Case Western Reserve University, to house a resistive heater coil with axial and rotational degrees of freedom. The resistive heater coil system enables thin aluminum specimens, held at the front-end of a heater resistant sabot, to be heate...

Access restricted. Please log in or start a trial to view this content.

Disclosures

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

The authors have nothing to disclose.

Acknowledgements

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

The authors would like to acknowledge financial support of the U.S. Department of Energy through the Stewardship Science Academic Alliance DOE/NNSA (DE-NA0001989 and DE-NA0002919) in conducting this research. Finally, the authors would like to thank Los Alamos National Lab for their collaboration in support of undergoing efforts in the current and future investigations.

Access restricted. Please log in or start a trial to view this content.

Materials

List of materials used in this article
NameCompanyCatalog NumberComments
99.999% commercial purity polycrystalline aluminumGoodfellowAL007970Material for flyer plate (sample)
H13 tool steelFabrication Center of CWRUN/AMaterial for the sample holder
Solution treat & age Inconel 718 alloyHigh Temp MetalsN/A(1.005/1.015)" Dia x 24", Material for target plate
Photoresist S1805MicroChemN/AMaterial of the photoresist for holographic grating
Developer CD-26MicroChemN/ADeveloper to the photoresist for holographic grating
Aluminum 6063 tubeMcMaster-Carr4568T19Material for the ring in target assembly
Black Delrin (R) Acetal Resin Rod (4-1/2" Dia.)McMaster-Carr8576K81Material for the Delrin holder in target assembly
White Delrin (R) Acetal Resin Rod (1/4" Dia.)McMaster-Carr8572K51Material for the Delrin pins in target assembly
Aluminum 6061 tubeMcMaster-Carr9056K24Material for the body in projectile assembly
Aluminum 6061 rodMcMaster-Carr8974K88Material for the cap in projectile assembly
Teflon sheetMcMaster-Carr8711K98Material for the key
LAVA-FF - Alumina Silicate discTechnical ProductsCWR-033116-1
LAVA-FF - Alumina Silicate tubeTechnical ProductsALR11515
Alumina Pan Slotted Head BoltCeramcoA83200PANSLT0.500
409 N70 Buna-N O-ringThe O-ring StoreB70409
Loctite Hysol 9412 adhesiveLoctite83107
High Temperature CementsOMEGA EngineeringOB-300
Extra fast-set epoxyEllsworth4001
Mylar sheetMcMaster-Carr8567K94

References

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,
  1. Davies, R. M. A critical study of the Hopkinson pressure bar. Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences. 240, 375-457 (1948).
  2. Kolsky, H. An investigation of the mechanical properties of materials at very high rates of loading. Proceedings of the Physical Society. Section B. 62, 676(1949).
  3. Gilat, A., Cheng, C. -S. Torsional split Hopkinson bar tests at strain rates above 104s− 1. Experimental Mechanics. 40, 54-59 (2000).
  4. Harding, J., Wood, E., Campbell, J. Tensile testing of materials at impact rates of strain. Journal of Mechanical Engineering Science. 2, 88-96 (1960).
  5. Clifton, R. J., Klopp, R. W. Pressure-shear plate impact testing. Metals handbook. 8, 230-239 (1985).
  6. Zuanetti, B., Wang, T., Prakash, V. Mechanical Response of 99.999% Purity Aluminum Under Dynamic Uniaxial Strain and Near Melting Temperatures. International Journal of Impact Engineering. 113, 180-190 (2017).
  7. Wang, T., Zuanetti, B., Prakash, V. Shock Response of Commercial Purity Polycrystalline Magnesium Under Uniaxial Strain at Elevated Temperatures. Journal of Dynamic Behavior of Materials. 3, 497-509 (2017).
  8. Dike, S., Wang, T., Zuanetti, B., Prakash, V. Dynamic Uniaxial Compression of HSLA-65 Steel at Elevated Temperatures. Journal of Dynamic Behavior of Materials. 3, 510-525 (2017).
  9. Okada, M., Liou, N. -S., Prakash, V., Miyoshi, K. Tribology of high speed metal-on-metal sliding at near-melt and fully-melt interfacial temperatures. Wear. 249, 672-686 (2001).
  10. Prakash, V., Clifton, R. J. Fracture Mechanics: Twenty Second Symposium (vol. 1). , Astm Special Technical Publication. (1992).
  11. Prakash, V., Mehta, N. Uniaxial Compression and Combined Compression-and-Shear Response of Amorphous Polycarbonate at High Loading Rates. Polymer Engineering and Science. 52, 1217-1231 (2012).
  12. Lee, Y., Prakash, V. Dynamic fracture toughness versus crack-tip speed relationship at lower than room temperature for high strength 4340VAR structural steels. Journal of the Mechanics and Physics of Solids. 46, 1943-1967 (1998).
  13. Lee, Y., Prakash, V. Dynamic brittle fracture of high strength structural steels under conditions of plane strain. International Journal of Solids and Structures. 36, 3293-3337 (1999).
  14. Yuan, F., Prakash, V., Lewandowski, J. J. Shear yield and flow behavior of a Zirconium-based bulk metallic glass. Mechanics of Materials. 42, 248-255 (2010).
  15. Shazly, M., Prakash, V., Draper, S. Mechanical behavior of Gamma-Met PX under uniaxial loading at elevated temperatures and high strain rates. International Journal of Solids and Structures. 41, 6485-6503 (2004).
  16. Klopp, R., Clifton, R., Shawki, T. Pressure-shear impact and the dynamic viscoplastic response of metals. Mechanics of Materials. 4, 375-385 (1985).
  17. Arvidsson, T. E., Gupta, Y., Duvall, G. E. Precursor decay in 1060 aluminum. Journal of Applied Physics. 46, 4474-4478 (1975).
  18. Gilat, A., Clifton, R. Pressure-shear waves in 6061-T6 aluminum and alpha-titanium. Journal of the Mechanics and Physics of Solids. 33, 263-284 (1985).
  19. Barker, L., Hollenbach, R. Shock wave study of the α⇄ε phase transition in iron. Journal of Applied Physics. 45, 4872-4887 (1974).
  20. Shazly, M., Prakash, V. Shock response of a gamma titanium aluminide. Journal of Applied Physics. 104, 083513(2008).
  21. Yuan, F., Prakash, V., Lewandowski, J. J. Spall strength and Hugoniot elastic limit of a Zirconium-based bulk metallic glass under planar shock compression. Journal of Materials Research. 22, 402-411 (2007).
  22. Yuan, F. P., Prakash, V., Lewandowski, J. J. Spall strength of a zirconium-based bulk metallic glass under shock-induced compress ion-and-shear loading. Mechanics of Materials. 41, 886-897 (2009).
  23. Prakash, V. A pressure-shear plate impact experiment for investigating transient friction. Experimental Mechanics. 35, 329-336 (1995).
  24. Kumar, P., Clifton, R. Optical alignment of impact faces for plate impact experiments. Journal of Applied Physics. 48, 1366-1367 (1977).
  25. Prakash, V. Time-resolved friction with applications to high speed machining: experimental observations. Tribology Transactions. 41, 189-198 (1998).
  26. Frutschy, K., Clifton, R. High-temperature pressure-shear plate impact experiments using pure tungsten carbide impactors. Experimental mechanics. 38, 116-125 (1998).
  27. Frutschy, K., Clifton, R. High-temperature pressure-shear plate impact experiments on OFHC copper. Journal of the Mechanics and Physics of Solids. 46, 1723-1744 (1998).
  28. Zaretsky, E., Kanel, G. I. Effect of temperature, strain, and strain rate on the flow stress of aluminum under shock-wave compression. Journal of Applied Physics. 112, 073504(2012).
  29. Grunschel, S. E. Pressure-shear plate impact experiments on high-purity aluminum at temperatures approaching melt. , Brown University. (2009).
  30. Zuanetti, B., Wang, T., Prakash, V. A Novel Approach for Plate Impact Experiments to Determine the Dynamic Behavior of Materials Under Extreme Conditions. Journal of Dynamic Behavior of Materials. 3, 64-75 (2017).
  31. Zuanetti, B., Wang, T., Prakash, V. A compact fiber optics-based heterodyne combined normal and transverse displacement interferometer. Review of Scientific Instruments. 88, 033108(2017).
  32. Zuanetti, B., Wang, T., Prakash, V. Mechanical response of 99.999% purity aluminum under dynamic uniaxial strain and near melting temperatures. International Journal of Impact Engineering. 113, 180-190 (2018).
  33. Duffy, T. S., Ahrens, T. J. Compressional sound velocity, equation of state, and constitutive response of shock-compressed magnesium oxide. Journal of Geophysical Research: Solid Earth. 100, 529-542 (1995).
  34. Tan, Y., et al. Hugoniot and sound velocity measurements of bismuth in the range of 11-70 GPa. Journal of Applied Physics. 113, 093509(2013).

Access restricted. Please log in or start a trial to view this content.

Reprints and Permissions

Request permission to reuse the text or figures of this JoVE article

Request Permission

Tags

Elevated Temperature Plate ImpactPressure Shear ExperimentsBreech end Sabot HeaterGas Gun ModificationsPhotonic Doppler VelocimeterReverse Geometry ImpactThermal Softening AnalysisHigh Temperature Materials TestingDynamic Material CharacterizationCustom Sabot Assembly

Related Articles