Tuesday, April 23, 2013

Why Do So Many Professors Consider the Shake Table II Essential To Their Labs?

In two previous blog posts about Quanser shake tables, we introduced the shake table family and then featured the largest of our offerings in this category, the Shake Table III.  In this blog post we cast the spotlight on the Shake Table II.

The most popular of all Quanser shake tables, the Shake Table II is found in university engineering labs all around the world.  A heavy load, bench-scale, single-axis shaker, this table features a wide surface that can easily hold a number of structures and accommodate complex as well as simple experiments. These factors, along with its convenient portability, make the Shake Table II particularly useful in teaching and research labs. Read on to see how it is being put to work today.
The most popular member of the Quanser Shake Table family, the bench-scale Shake Table II simulates earthquake movements along a single axis and can move a substantial 7.5 kg load at 2.5 g.  It features a wide surface that  can accommodate several structures and increase the complexity of your experiments.

University of East London, London, UK:  Easy to use, portable and ideal for teaching
Students from more than 100 countries attend the University of East London, and many of the students who study civil engineering return to countries that are affected by seismic activity. Dr. Mihaela Anca Ciupala, Program Leader at the university’s School of Computing, Information Technology and Engineering (CITE), is very pleased with the learning opportunities made possible with Quanser’s Shake Table II.

The table is used in a number of study areas, including the determination of natural frequencies in multi-DOF structures, and the seismic response of building frames. The Shake Table II provides students with valuable, hands-on experimental experience along with a better understanding of the theoretical concepts presented in CITE’s Civil Engineering courses. It has also enabled research in such areas as seismic response of base-isolated structures and soil-structure interaction.

Dr. Anca Ciupala cites several reasons the Shake Table II was added to their lab. “It’s ideal for teaching purposes because it is easy to use, accessible, portable. And since it has simple software operation, it helps a large number of students to understand and complete projects in a relatively short time.”

University of Alaska, Anchorage, USA:  Provides a real world model that makes abstract seismic concepts easier to understand
Alaska has felt the terrible effects of at least one catastrophic earthquake in the past, and with an eye to preventing serious damage in the future, Professor Zhaohui Yang of the University of Alaska’s Department of Civil Engineering wanted to help the general public experience a vivid demonstration the nature of seismic destruction.

To that end, he and his students created a series of mini-laboratories to showcase structural and geotechnical aspects of earthquake damage, including the effects of a mass damper on a one-story building, as well as the effects of liquefaction on a one-story building. According to Professor Yang, these simulations “provided a real-world model to an otherwise abstract concept, making these concepts easier for the general public to understand.”

The Shake Table II served Professor Yang’s purposes because “it can accurately mimic seismic activity and test building seismic performance”.  The Shake Table II’s small scale and portability offered additional advantages, since it is simple to work with in the lab and easy to transport to public demonstration sites.

The Shake Table workstation consists of (from right to left)  the blue Shake Table II; on top of it is the one-story Quanser-made model structure, which is connected to the power module in the center of the photo; MATLAB software can be seen on the computer screen.  (University of Alaska photos)

Tongji University, Shanghai, China: Worldwide popularity makes it ideal for collaborative projects
Professor Haibei Xiong, Dean of Tongji University’s College of Civil Engineering, acquired Tongji’s first Shake Table II in 2006 and two more in 2012. The shake tables are used for teaching, conducting structural experiments, and especially for student structural competitions. They use QUARC® with MATLAB®/Simulink® software, and an active mass damper for demo purposes.

Professor Xiong finds the shake tables worthy additions to their lab for several reasons.  To begin with, the shake tables’ small scale means students can do experiments easily and safely. There is no additional maintenance cost, so a lab assistant isn’t needed.

She appreciates the fact that QUARC’s open architecture control software, working with MATLAB/Simulink, makes it easy to control several tables at the same time. That capability made the school decide to acquire additional Shake Table II’s. This allows them to conduct multi-point shaking experiments on a bridge structure, and also work on shaking a bigger structure with several small shake tables.

The fact that many civil engineering schools in China are doing collaborative work with universities in North America that use the Shake Table II is another reason for the Quanser Shake Table II’s popularity and presence at Tongji University. The school plans to acquire an additional two Shake Table II’s in the near future. 

Purdue University, West Lafayette, Indiana, USA: Sheer convenience of complete system provides true flexibility
Professor Shirley Dyke is professor of mechanical engineering and civil engineering, at the School of Civil Engineering at Purdue University.

She uses the Shake Table II and an Active Mass Damper Controller to teach Structural Dynamics to her first year graduate students. Specifically the Shake Table helps demonstrate the dynamics of building structures.  A key reason the Shake Table has a place in her lab is simple convenience. “The system consists not only of a shake table, but includes accelerometers, test structures, data acquisition and a computer to record data and control the shake table itself,” she says. “It gives us desired flexibility in performing experiments.”

In 1999, Professor Dyke was one of the founders of the University Consortium on Instructional Shake Tables (UCIST), a group whose goal was to introduce earthquake simulators into classroom teaching.  In fact, the Shake Table II was built in cooperation with UCIST, and UCIST now recommends it as a turnkey solution for teaching structural dynamics to civil engineers.

Cornell University, New York, USA:  Brings earthquake simulations to life in the classroom
Professor Anthony Ingraffea believes that his students grasp structural dynamics concepts better when those concepts are brought to life through real world earthquake simulations in the classroom. Cornell University’s School of Civil and Environmental Engineering uses a Quanser Shake Table II for that reason.

Typically Professor Ingraffea organizes students into teams that design and build model structures, then test the structural integrity of their designs in a big “shake-off”. The Shake Table and the simulations effectively mimic the real world and bring theory to life for the students.  Professor Ingraffea feels that the Quanser Shake Table II has motivated five generations of Cornell freshmen to better understand the theory of structural dynamics.

University of California, Davis, California, USA:  An essential tool for education, research and outreach
The Shake Table II is a very popular lab tool at University of California, Davis, according to Nima Tafazzoli, postdoctoral researcher in the school’s Department of Civil and Environmental Engineering. It’s used for teaching, research, and outreach.

At the undergraduate level, it helps professors teach classes and seminars in civil and environmental engineering. At the graduate level, it demonstrates the response of single or multiple degrees of freedom structures subjected to earthquakes. As a research tool, the Shake Table II is involved in several projects at Departments of Civil and Environmental Engineering as well as Mechanical and Aeronautical Engineering when dynamic load is required to be applied to the system. The Shake Table II has also been featured in outreach programs, and is an essential tool in entry in the national seismic design competitions.  UC Davis chose the Shake Table II because it is easy to set up, use and transport, without requiring the work of a group of lab assistants. They find it an engaging way to demonstrate the actual behavior of structures and see it as safer to use than most lab equipment, especially with inexperienced students.

Stay tuned to our blog for another post in this Shake Table series. For more information about Quanser Shake Table solutions, click here.

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