Shake tables are widely used for experimental studies in structural engineering, e.g. for measuring structural responses, for calculating mode shapes, and for studying the dynamic behavior of down-scaled structures in the laboratory. In this respect, educational institutions usually prefer hydraulic shake tables due to the ability to impose motion on medium-scale structures. However, for small-scale structures, hydraulic shake tables may be expensive in comparison with the overall project budgets of educational institutions in terms of both investment and maintenance costs. As an alternative, electro-mechanical shake tables are used for small-scale structures, but the cost may be still high for small projects. Small projects may benefit from building customized, low-cost shake tables, using off-the-shelf components. However, approaches towards devising low-cost shake tables for small projects have been scarce. In this project, the design, the implementation, and validation of a low-cost single-axis shake table is to be carried out. The shake table must be composed of off-the-shelf components, controlled by a low-cost microprocessor, and the motion parameters should be defined through a user interface. For validation, the motion of the shake table may be recorded using displacement sensors, and the sensor displacement data, reflecting the shake table output, is then compared with the user-defined motion parameters, which serve as shake table input.
The tasks comprising this master´s thesis are summarized as follows:
- Research on existing low-cost shake tables for laboratory test structures. In particular, the shake-table implemented at the Institute of Digital and Autonomous Construction (material and details about the project will be provided) is to be studied. Improvements on the design as well as on the hardware components of the shake table developed at the IDAC are to be proposed.
- Design of the low-cost shake table. The requirements (e.g., maximum and minimum rotation of the servomotor of the shake table) are identified. A list of hardware components that fulfill the requirements of the system is to be created for the new, improved low-cost shake table. An IoT-layered architecture is created to describe the software requirements of the low-cost shake table.
- Implementation of the low-cost shake table. Upon availability of the hardware components, the shake table is to be built. The software of the system is to be implemented, meeting the requirements that have been identified in the previous step. Basic parameters, such as frequency and amplitude of accelerations, should be controlled remotely via an IoT user interface of a web application.
- Validation of the shake-table. Acceleration data is to be streamed remotely into the microprocessor of the shake-table. The motor of the shake-table should react according to the input stream of data. Benchmark accelerometers are located on the surface of the shake table and continuously record acceleration measurements during the validation experiment. The shake-table is considered validated if the output of the benchmark accelerometers is the same as the accelerations that are streamed into the microprocessor of the shake table.
Consultations are to be held with the supervisors at least once a month during the working period. The thesis must be submitted both digitally (PDF) and as hardcopy (2 copies). A summary of the thesis in the form of a poster or a short video (~2 minutes) must be available before the defense. The source files of the thesis (Word or LaTeX), the source files of embedded figures and of other related files, and other sources that are not freely available must be submitted together with the thesis.