The Dynamic Behavior and Multifunctional Material Laboratory is equipped with advanced facilities required for conducting dynamic experiments at different loading conditions.
The single stage Shock Tube apparatus shown in Fig.1 has been developed by the investigators and is being used extensively for testing of materials subjected to shock loading. The Shock Tube consisted of a 1.8m long driver section and a 5.5m long driven section separated by a diaphragm, having a constant inside diameter of 76.2 mm over the length of the tube. Sheets of Mylar (stretched polyester film) are utilized as the material of choice for the diaphragm. The velocity and magnitude of the pressure wave produced by the Shock Tube can be varied by increasing or decreasing the number of Mylar sheets comprising the diaphragm. The system can provide up to 10 MPa reflected pressure at a shock wave velocity of 1200 m/s (Mach 4). To provide protection for investigators, the outlet region of the shock tube exits into an enclosed, hardened chamber with shatter-proof windows, providing visual access for imaging while also ensuring the safety of research personnel.
Hot PressA temperature/pressure controlled hot press equipment used for fabrication of advanced materials, based on powder metallurgy routes. The material systems which can be processed with this equipment include high-temperature ceramic/metallic materials, metal/ceramic functionally graded materials and ceramic matrix composites. Temperature of up to 2000 C with a maximum pressure 20 MPa can be achieved in the vacuum furnace of the hot press, yielding to net-shape, near-to-full density parts.
Hopkinson Pressure Bar
DBMML houses both a compressed air driven compression Split Hopkinson Pressure Bar and a tension Split Hopkinson Bar shown. The compression bar is shown in Figure 2(a). The tensile specimen holder is shown in Figure 2(b). In this system, projectile speeds up to 152 m/s are possible, providing strain rates up to 4000?/s. Projectiles are 25.4 mm (1.0 in) diameter and can handle compressive specimens up to 24.1 mm (0.95 in) in diameter. Tensile specimens up to 12.7 mm (0.5 in) can also be impulsively loaded in this system through modification of the loading process. Recently an automated hydraulic Torsional Hopkinson Bar (THB) was developed and is shown in Figure 3. The THB is generally used to study the dynamic shear properties of materials. The main parts of the THB apparatus are two elastic bars (incident and transmitter), a clamp with a sudden releasing mechanism, and a mechanism to create torque in the incident bar. The position of the clamp determines the duration of the stress pulses while also controlling the strain applied to the sample. As with the other dynamic facilities, the THB offers direct visual access to the specimen during the loading process so that the Ultra HS3 with the stereo-microscope system can be used to obtain data during the experiment. As shown in Figure 4, impact studies for tension, cross-tension, and three-point bend and compression specimens can be performed using an Instron Model 8140 Drop-Weight Tower. This system provides up to 18,678 J (13,776 ft-lbf) of energy at a velocity of 6.7 m/s (22 ft / s) using an impacting mass ranging from 227 to 783 kg (500 to 1725 lbm). Here, the wire steel door will be modified through addition of a Lexan window to offer direct visual access to the specimen during the loading process so that the Ultra HS3 can be used to obtain data during the experiment. Other facilities required for the proposed project are available at the University of South Carolina, either at a common facility or in individual labs. For example electron microscopy center has SEM, TEM and related imaging techniques for material characterization. In addition, the following facilities are also available for our use;
Two Photron (SAX2) High Speed Cameras
Other major equipments exist at DBMML
- A state-of-the-art pair of ultra-high speed digital cameras (IMACON 200) a. Framing rate of 5 ns ( 200 milion frames per second) .
- High speed Infra-red camera
- A gas-driven compression split Hokinson pressure bar apparatus a. It has 1/2 inch and 1 inch diameter bars
- Torsional Hopkinson bar
- High temperature hot press a. Temperature up to 2000 °c
b. Pressure up to 20 tons
Common User Facilities
Center for Mechanics and Materials and NDE in the Department of Mechanical Engineering has following facilities
- Three MTS hydraulic tension testing systems with specialized software for fatigue testing
- One Instron hydraulic testing system with Centorr vacuum furnace
- Two single-axis MTS vibration table
- Dynamic test equipment capable of impact loading of materials at speeds up to 180 mph
- Thermotron environmental chamber capable of temperature, humidity, boil, freeze/thaw
- Weatherometer chamber for intense ultraviolet and humidity aging exposure
MTS tensile test machines
- MTS 810 capable of static and cyclic loadings up to 500kN
- Instron 8501 capable of up to 10 Hz cyclic loading for fatigue testing
- MTS equipped with ATS3710 oven can perform tensile test at temperature between -300F and 800F
The Department of Mechanical Engineering of the University of South Carolina has a fabrication facility.