Dynamic Mechanics of Materials Laboratory: Materials
Materials
Data from a Compression Split-Hopkinson Bar Experiment
Sample data from a compression SHB experiment on a 2024-T351 aluminum specimen are shown below in Figure 1, Figure 2 and Figure 3. Figure 1 presents the wave data from the experiment. Engineering stress, strain rate and engineering strain in the specimen are plotted versus time in Figure 2. The black and gray traces in Figure 3 represent the engineering and true stress-strain curves, respectively.
Three dimensional digital image correlation can be used to measure the surface strains of a specimen loaded with this apparatus. DIC data from a 6061-T6 aluminum specimen tested on the compression SHB are shown in Figure 4. Strain contours from the ends of the incident and transmitter bars are also shown. Data acquired with DIC provide an independent measurement of strain that can be compared to data calculated using traditional SHB data reduction techniques.
Data From a Tension Split-Hopkinson Bar Experiment
Sample data from a tension SHB experiment on a 2024-T351 aluminum specimen are shown below in Figure 1, Figure 2 and Figure 3. Figure 1 presents wave data from the experiment. Engineering stress, strain rate and engineering strain in the specimen are plotted versus time in Figure 2. Figure 2 shows that the shear strain rate is relatively constant at 500.0 s-1 after a 40 microsecond rise time. Engineering and true stress versus strain curves are shown in Figure 3.
Three dimensional digital image correlation can be used to measure the surface strains of a specimen loaded with this apparatus. Surface strains of a titanium alloy (Ti-6Al-4V) specimen tested on the tension SHB are shown in Figure 4. The region of high strains in the center of the specimen is clear evidence of a necking localization.
Data from a Torsion Split-Hopkinson Bar Experiment
Sample data from a torsion SHB experiment on a half-hard (H02) C464 brass specimen are shown below in Figure 1, Figure 2 and Figure 3. Figure 1 presents wave data from the experiment. Shear stress, shear strain rate and shear strain in the specimen are plotted versus time in Figure 2. Figure 2 shows that the shear strain rate is relatively constant at 5000.0 s-1after a 50 microsecond rise time. The resultant shear stress versus shear strain curve is shown in Figure 3.
Three dimensional digital image correlation can be used to measure the surface strains of a specimen loaded with this apparatus. Surface strains of an UFG (Ultra-Fine Grain) aluminum specimen tested on the torsion SHB are shown in Figure 4.
Data from a Large Diameter Compression Split-Hopkinson Bar Experiment
Data from a dynamic compression test on a woven composite material are presented below. This experiment was conducted using the large diameter SHB apparatus. The specimen is a flat composite slab that is epoxied into steel adaptors, see Figure 1. The composite is painted with a white contrast pattern on a black base-coat for 3D DIC measurements.
Wave data from the experiment is shown in Figure 2, while a stress strain curve is presented in Figure 3.
Data from an Intermediate Strain Rate Test
Data from an intermediate strain rate experiment on a PR-520 epoxy resin specimen are shown below in Figure 1 and Figure 2. Figure 1 presents engineering stress and strain history data. The average strain rate for this experiment is ~95.0 s-1. True stress versus true strain curves for PR-520 covering a wide range of strain rates using three different test methods are presented in Figure 2. Black traces in Figure 2 are from experiments on a servohydraulic load frame while gray traces are from compression split-Hopkinson bar tests. The red trace, which lies between the servohydraulic and Hopkinson bar data, is from an experiment on the intermediate strain rate apparatus.
