HBK technology is used for research on experimental investigations on the dynamic behavior and fracture of composite materials at the University of Siegen.
For raising the standards of production and living, the measuring of electrical or physical quantities, such as current, voltage, strain, temperature, and pressure, are essential. This is why, over the years, several research institutes at the University of Siegen have used measurement technology in their research projects. As far back as in the beginning of 1975, strain gauges and measuring equipment manufactured by HBK were employed at the University of Siegen. Later, HBK measuring systems with three or even six and more amplifiers were used to determine strain and/or displacement. Some of them have been in use for more than four decades, which speaks for itself. Recently, several HBK Genesis HighSpeed data acquisition (DAQ) systems, such as GEN7t and GEN17tA, have been used in projects at different institutes at the University of Siegen.
Since materials respond differently to static and dynamic loadings, the investigation of material behavior is a topic of interest for research teams.
Mohammad Reza Khosravani, a doctoral student at the time and now a PhD in Mechanical Engineering, has recently explored “experimental investigations on the dynamic behavior and fracture of composite materials” at the Institute of Solid Mechanics at University of Siegen. “Over the past few years, we used HBK products for performing the above mentioned experimental research”, he explains. “In detail, we performed investigations on the fracture mechanics of two different composite materials—sandwich composite T-joints and ultra-high performance concrete (UHPC). In this regard, we used two split Hopkinson pressure bars (SHPB) in our laboratory which were equipped with HBK products and a high speed camera.” The results have been published in several peer-reviewed journals.
HBK’s measuring system and strain gauges were used in the experimental tests on the sandwich T-joints. With the help of the strain gauges, the strain on the interface of the sandwich joint was determined. In a series of tensile tests under different loading rates, ultra-high speed video cameras were used for the digital image correlation (DIC) technique. The camera was triggered by a signal generated by the strain gauges mounted on the specimens. The images with the DIC technique allowed the researcher to determine the position of the crack and to study the process of the interfacial failure. Since these images are an important element of controversial data, the trigger signal from the strain gauges was a crucial issue that could successfully be solved by using HBK strain gauges. As Dr.-Ing. Mohammad Reza Khosravani sums up,
“When investigating the dynamic behavior of UHPC material, we used a split Hopkinson pressure bar (SHPB) and determined the mechanical properties of UHPC material under high rates of loading”, explains Dr.-Ing. Khosravani. Both incident and transmission bars as well as tested specimens were equipped with HBK strain gauges. The SHPB was connected to a Genesis HighSpeed GEN7t data acquisition system. This system is a fast data recorder that offers high flexibility and an outstanding performance. The DAQ system employed in the tests includes a transient RAM up to 106 samples per second and allows for use of 4 channels at the same time.
“The GEN7t mainframe holds 7 input cards and we could add the desired channels, which is a benefit of this system. HBK’s Genesis HighSpeed data acquisition system can be considered as one of the most powerful and sophisticated systems available in the global market. For various researches, we used different Genesis HighSpeed systems that are high-end DAQ systems combining transient recording and data streaming,” says Dr.-Ing. Khosravani. “DAQ systems produced by HBK can be configured for the intended duration and recording size. As an advantage of the HBK products, and particularly the Genesis HighSpeed series, it is worth mentioning that these systems can be extended for the desired purposes. In this respect, we used the basic data acquisition blocks and determined the capabilities that we needed in the system. The design of the hardware allowed us to configure the number of channels.”
Another advantage mentioned by the researcher is that the strain gauges and the measuring system are manufactured by the same producer and, thus, function extremely well together. In addition to the hardware, the research team used HBK’s Perception software which is a multi-language software.
With the data provided by the strain gauges and DAQ system, stress-strain curves of sandwich T-joints under static and dynamic loads were created. The obtained curves indicate the load carrying capacities of these structural elements.
This is a unique high speed measurement software that automatically detects all available Genesis HighSpeed systems. With Perception, fast and reliable processing is achievable and StatStream technology enables the software to visualize up to 10 gigabytes of data in 10 seconds. In addition, control and updates can be carried out from any computer.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.