High Speed Video Camera
Shimadzu (Hyper Vision HPV-X2) high speed video camera that has recording speed of 10 million frames/sec; continuous recording of 256 frames; with a resolution of 100,000 pixels (400 horizontal and 250 vertical); and with exposure time as low as 50ns is available.
A pendulum based linear impactor for testing foot ball and ice Hockey players helmets is available. This facility was built to the specification of ND081 as defined by the National Operating Committee on Standards for Athletic Equipment (NOCSAE). Helmets can be tightly positioned on magnesium head and housed with accelerometers in the center of the head to measure three angular and three linear accelerations using LabView data acquisition system. This facility can be used in conjunction with high speed imaging to capture real-time impacts. This facility is designed and built by graduate research assistant, Mr. Jared Correia.
Drop Weight Tower Experimental Setup for Medium Strain Rate Testing
This guided drop weight tower can be used to drop a mass of from a maximum height of 2.4 m (8 foot). Drop weight and projectile geometry can be adjusted according to test protocols such as ASTM D 1596 and NOCSEA standards. This facilities is instrumented with high resolution accelerometers to measure the g-values and 7500 lb load sensor to measure the force loss or energy absorption of the tested materials. This facility has been used in conjunction with a in-house built shear loading fixture to determine the energy absorption under shear impact loads in addition to compression impact loads. This facility is designed and built by an undergraduate research assistant, Mr. Diarny Fernandes.
Chalivendra’s lab houses split Hopkinson pressure bar setups for tension, compression, fracture experiments at high strain rates. The setup has steel, titanium, and aluminum (solid incident and hallow transmission bar for soft materials) bars. Using this setup, the high strain rate behavior of metals, polymers, composites, and soft materials such as hydrogels can be investigated. The gas gun assembly along with different projectiles allow to achieve various strain rates ranging from 2000/s to 8,000/s. The high frequency and high bandwidth data acquisition system is used to capture loading history to determine dynamic true stress-strain behavior of above materials. The compression Hopkinson pressure bar setup was designed and built by my first Masters student, Mr. John Crowley. Very recently, another graduate research assistant, Mr. Austin Taylor and the machinist, Mr. Paul Sousa designed and built the tensile Hopkinson pressure bar setup.
Two-dimensional digital image correlation along (DIC) with Instron materials testing can be used to determine constitutive materials behavior and fracture characterization of various kind of materials such as metals, polymers and composites. 2.3 Megapixel (1920 x 1200 @ 155 fps) Digital Camera is used to capture full-field deformation and later can be used in-plane strain fields and elastic properties of materials. Full-field deformation around the crack-tip can be used to determine fracture toughness in both homogeneous and non-homogeneous materials.
Atomic force microscopy (supplied by Park Systems) consists of non-contact mode, contact mode and current mode is available. This facility can be used to obtain surface topography of various materials such as metals, polymers, and cells/tissues (with liquid cell). This facility can be used to indent soft materials such as polymers and biological materials such as cells and tissues. In addition, using current mode, local current–voltage (I–V) characteristics and current-transporting properties in the confined domain or area can be obtained from a conductive surface.